idnits 2.17.1 draft-ietf-sacm-nea-swima-patnc-03.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- == There are 5 instances of lines with non-RFC6890-compliant IPv4 addresses in the document. If these are example addresses, they should be changed. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (February 27, 2018) is 2242 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Looks like a reference, but probably isn't: '1' on line 4208 == Missing Reference: 'RFC-to-be' is mentioned on line 4108, but not defined -- Possible downref: Non-RFC (?) normative reference: ref. 'NIST8060' -- Possible downref: Non-RFC (?) normative reference: ref. 'SWID09' -- Possible downref: Non-RFC (?) normative reference: ref. 'SWID15' Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SACM C. Schmidt 3 Internet-Draft D. Haynes 4 Intended status: Standards Track C. Coffin 5 Expires: August 31, 2018 The MITRE Corporation 6 D. Waltermire 7 National Institute of Standards and Technology 8 J. Fitzgerald-McKay 9 United States National Security Agency 10 February 27, 2018 12 Software Inventory Message and Attributes (SWIMA) for PA-TNC 13 draft-ietf-sacm-nea-swima-patnc-03 15 Abstract 17 This document extends "PA-TNC: A Posture Attribute (PA) Protocol 18 Compatible with Trusted Network Connect (TNC)" (RFC 5792) by 19 providing specific attributes and message exchanges to allow 20 endpoints to report their installed software inventory information to 21 a NEA server, as defined in "Network Endpoint Assessment (NEA): 22 Overview and Requirements" (RFC 5209). 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at https://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on August 31, 2018. 41 Copyright Notice 43 Copyright (c) 2018 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (https://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 59 1.1. Network Endpoint Assessment (NEA) . . . . . . . . . . . . 5 60 1.2. Conventions Used in This Document . . . . . . . . . . . . 6 61 1.3. Definitions . . . . . . . . . . . . . . . . . . . . . . . 7 62 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 8 63 2.1. Supported Use Cases . . . . . . . . . . . . . . . . . . . 8 64 2.1.1. Use Software Inventory as an Access Control Factor . 8 65 2.1.2. Central Stores of Up-to-Date Endpoint Software 66 Inventory Data . . . . . . . . . . . . . . . . . . . 8 67 2.1.3. PA-TNC Use Cases . . . . . . . . . . . . . . . . . . 9 68 2.2. Non-supported Use Cases . . . . . . . . . . . . . . . . . 9 69 2.3. Specification Requirements . . . . . . . . . . . . . . . 10 70 2.4. Non-Requirements . . . . . . . . . . . . . . . . . . . . 11 71 2.5. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 11 72 2.6. Non-Assumptions . . . . . . . . . . . . . . . . . . . . . 11 73 3. System Requirements . . . . . . . . . . . . . . . . . . . . . 12 74 3.1. Data Sources . . . . . . . . . . . . . . . . . . . . . . 12 75 3.2. Data Models . . . . . . . . . . . . . . . . . . . . . . . 13 76 3.3. Basic Attribute Exchange . . . . . . . . . . . . . . . . 14 77 3.4. Core Software Reporting Information . . . . . . . . . . . 16 78 3.4.1. Software Identifiers . . . . . . . . . . . . . . . . 16 79 3.4.2. Data Model Type . . . . . . . . . . . . . . . . . . . 17 80 3.4.3. Record Identifiers . . . . . . . . . . . . . . . . . 18 81 3.4.4. Software Locators . . . . . . . . . . . . . . . . . . 18 82 3.4.5. Source Identifiers . . . . . . . . . . . . . . . . . 19 83 3.4.6. Using Software and Record Identifiers in SWIMA 84 Attributes . . . . . . . . . . . . . . . . . . . . . 20 85 3.5. Targeted Requests . . . . . . . . . . . . . . . . . . . . 21 86 3.6. Monitoring Changes in an Endpoint's Software Inventory 87 Evidence Collection . . . . . . . . . . . . . . . . . . . 22 88 3.7. Reporting Change Events . . . . . . . . . . . . . . . . . 24 89 3.7.1. Event Identifiers . . . . . . . . . . . . . . . . . . 25 90 3.7.2. Core Event Tracking Information . . . . . . . . . . . 27 91 3.7.3. Updating Inventory Knowledge Based on Events . . . . 27 92 3.7.4. Using Event Records in SWIMA Attributes . . . . . . . 27 93 3.7.5. Partial and Complete Lists of Event Records in SWIMA 94 Attributes . . . . . . . . . . . . . . . . . . . . . 28 95 3.7.6. Synchronizing Event Identifiers and Epochs . . . . . 30 96 3.8. Subscriptions . . . . . . . . . . . . . . . . . . . . . . 32 97 3.8.1. Establishing Subscriptions . . . . . . . . . . . . . 32 98 3.8.2. Managing Subscriptions . . . . . . . . . . . . . . . 33 99 3.8.3. Terminating Subscriptions . . . . . . . . . . . . . . 33 100 3.8.4. Subscription Status . . . . . . . . . . . . . . . . . 34 101 3.8.5. Fulfilling Subscriptions . . . . . . . . . . . . . . 34 102 3.8.5.1. Subscriptions Reporting Inventories . . . . . . . 36 103 3.8.5.2. Subscriptions Reporting Events . . . . . . . . . 36 104 3.8.5.3. Targeted Subscriptions . . . . . . . . . . . . . 37 105 3.8.5.4. No Subscription Consolidation . . . . . . . . . . 38 106 3.8.5.5. Delayed Subscription Fulfillment . . . . . . . . 38 107 3.9. Error Handling . . . . . . . . . . . . . . . . . . . . . 39 108 4. Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 41 109 4.1. Direct Response to a SWIMA Request . . . . . . . . . . . 41 110 4.2. Subscription-Based Response . . . . . . . . . . . . . . . 41 111 4.3. Required Exchanges . . . . . . . . . . . . . . . . . . . 42 112 5. Software Inventory Messages and Attributes . . . . . . . . . 42 113 5.1. PA Subtype (AKA PA-TNC Component Type) . . . . . . . . . 42 114 5.2. SWIMA Attribute Overview . . . . . . . . . . . . . . . . 43 115 5.3. Message Diagram Syntax . . . . . . . . . . . . . . . . . 45 116 5.4. SWIMA Attribute Enumeration . . . . . . . . . . . . . . . 45 117 5.5. Normalization of Text Encoding . . . . . . . . . . . . . 45 118 5.6. Request IDs . . . . . . . . . . . . . . . . . . . . . . . 45 119 5.7. SWIMA Request . . . . . . . . . . . . . . . . . . . . . . 46 120 5.8. Software Identifier Inventory . . . . . . . . . . . . . . 50 121 5.9. Software Identifier Events . . . . . . . . . . . . . . . 54 122 5.10. Software Inventory . . . . . . . . . . . . . . . . . . . 59 123 5.11. Software Events . . . . . . . . . . . . . . . . . . . . . 62 124 5.12. Subscription Status Request . . . . . . . . . . . . . . . 67 125 5.13. Subscription Status Response . . . . . . . . . . . . . . 68 126 5.14. Source Metadata Request . . . . . . . . . . . . . . . . . 70 127 5.15. Source Metadata Response . . . . . . . . . . . . . . . . 71 128 5.16. PA-TNC Error as Used by SWIMA . . . . . . . . . . . . . . 73 129 5.16.1. SWIMA_ERROR, 130 SWIMA_SUBSCRIPTION_DENIED_ERROR and 131 SWIMA_SUBSCRIPTION_ID_REUSE_ERROR Information . . . 76 132 5.16.2. SWIMA_RESPONSE_TOO_LARGE_ERROR Information . . . . . 77 133 5.16.3. SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR Information . . 79 134 6. Supported Data Models . . . . . . . . . . . . . . . . . . . . 81 135 6.1. ISO 2015 SWID Tags using XML . . . . . . . . . . . . . . 81 136 6.1.1. Guidance on Normalizing Source Data to ISO 2015 SWID 137 Tags using XML . . . . . . . . . . . . . . . . . . . 81 138 6.1.2. Guidance on Creation of Software Identifiers from ISO 139 2015 SWID Tags . . . . . . . . . . . . . . . . . . . 82 140 6.2. ISO 2009 SWID Tags using XML . . . . . . . . . . . . . . 82 141 6.2.1. Guidance on Normalizing Source Data to ISO 2009 SWID 142 Tags using XML . . . . . . . . . . . . . . . . . . . 82 143 6.2.2. Guidance on Creation of Software Identifiers from ISO 144 2009 SWID Tags . . . . . . . . . . . . . . . . . . . 83 146 7. Security Considerations . . . . . . . . . . . . . . . . . . . 83 147 7.1. Evidentiary Value of Software Inventory Evidence Records 83 148 7.2. Sensitivity of Collected Records . . . . . . . . . . . . 84 149 7.3. Integrity of Endpoint Records . . . . . . . . . . . . . . 85 150 7.4. SWIMA-PC Access Permissions . . . . . . . . . . . . . . . 85 151 7.5. Sanitization of Record Fields . . . . . . . . . . . . . . 86 152 7.6. PA-TNC Security Threats . . . . . . . . . . . . . . . . . 86 153 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 86 154 9. Relationship to Other Specifications . . . . . . . . . . . . 87 155 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 88 156 10.1. PA Subtypes . . . . . . . . . . . . . . . . . . . . . . 88 157 10.2. Registry for PA-TNC Attribute Types . . . . . . . . . . 88 158 10.3. Registry for PA-TNC Error Codes . . . . . . . . . . . . 89 159 10.4. Registry for Software Data Models . . . . . . . . . . . 90 160 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 91 161 11.1. Normative References . . . . . . . . . . . . . . . . . . 91 162 11.2. Informative References . . . . . . . . . . . . . . . . . 92 163 11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 93 164 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 93 166 1. Introduction 168 Knowing the list of the software installed on endpoints is useful to 169 understand and maintain the security state of a network. For 170 example, if an enterprise policy requires the presence of certain 171 software and prohibits the presence of other software, reported 172 software installation information can be used to indicate compliance 173 and non-compliance with these requirements. Endpoint software 174 installation inventory lists (hereinafter "software inventories") can 175 further be used to determine an endpoint's exposure to attack based 176 on comparison to vulnerability or threat alerts against identified 177 software's patch level data. These are some of the highly useful 178 management use cases supported by software inventory data. 180 Software Inventory Message and Attributes (SWIMA) for PA-TNC provides 181 a standardized method for exchanging software inventory data that 182 includes a unique software identifier associated with a specific 183 version of a software product. SWIMA can also convey metadata about 184 software products beyond this identifier. SWIMA enables software 185 identification, installation, and characterization information to be 186 be transported to a central server from any endpoint that supports 187 this specification. Such information can come from multiple sources, 188 including tag files (such as ISO SWID tags [SWID15]), reports from 189 third party inventory tools, output from package managers, and other 190 sources. SWIMA does not standardize how software is detected, 191 instead relying on a set of "data sources" to provide information 192 about installed software. Instead, SWIMA provides a flexible 193 transport capable of conveying this information regardless of how it 194 is expressed. 196 This specification is designed to only report software that is 197 installed on a target endpoint. In particular, it does not monitor 198 or report information about what software is running on the endpoint. 199 Likewise, it is not intended to report individual files, libraries, 200 installation packages, or similar artifacts. While all of this 201 information has its uses, this information requires different 202 metadata and monitoring methods. As a result, this specification 203 focuses solely on software inventory information, leaving reporting 204 of other classes of endpoint information to other specifications. 206 Note that while this specification focuses on "software inventory", 207 the mechanisms it describes could also be used to convey information 208 about firmware and operating systems associated with an endpoint. 209 The focus on software throughout this document should not be read as 210 excluding the use of SWIMA for these other purposes. 212 This specification defines a new set of PA-TNC attributes, which are 213 used to communicate requests for software inventory information and 214 software installation change events. The exchange of these messages 215 allows software inventory information to be sent to a NEA Server, 216 which can make this information available to other applications. 218 Part of the motivation for the development of SWIMA was to support 219 the IETF's Security Automation and Continuous Monitoring (SACM) 220 architecture. More details about SWIMA's role in SACM appear in 221 Section 9. However, SWIMA has no dependencies on any part of SACM 222 and is usable wherever the NEA architecture is employed. 224 1.1. Network Endpoint Assessment (NEA) 226 SWIMA defines extensions to the PA-TNC specification, which is part 227 of the Network Endpoint Assessment (NEA) architecture. The NEA 228 specifications define an open solution architecture that enables 229 network operators to collect and utilize information about endpoint 230 configuration and state. This information can be used to enforce 231 policies, monitor endpoint health, and for many other activities. 232 Information about the software present on an endpoint is an important 233 consideration for such activities. The new PA-TNC attributes defined 234 in this document are used to communicate software inventory evidence, 235 collected from a range of possible sources, from the posture 236 collector on the endpoint to the posture validator on a NEA Server 237 using the PA-TNC interface, as shown in Figure 1 below. 239 +-------------+ +--------------+ 240 | Posture | <--------PA--------> | Posture | 241 | Collectors | | Validators | 242 | (1 .. N) | | (1 .. N) | 243 +-------------+ +--------------+ 244 | | 245 | | 246 | | 247 +-------------+ +--------------+ 248 | Posture | | Posture | 249 | Broker | <--------PB--------> | Broker | 250 | Client | | Server | 251 +-------------+ +--------------+ 252 | | 253 | | 254 +-------------+ +--------------+ 255 | Posture | | Posture | 256 | Transport | <--------PT--------> | Transport | 257 | Client | | Server | 258 | (1 .. N) | | (1 .. N) | 259 +-------------+ +--------------+ 260 NEA CLIENT NEA SERVER 262 Figure 1: NEA Reference Model 264 To better understand this specification, the reader should review the 265 NEA reference architecture as described in the Network Endpoint 266 Assessment (NEA): Overview and Requirements [RFC5209]. The reader 267 should also review the PA-TNC interfaces as defined in RFC 5792 268 [RFC5792]. 270 This document is based on standards published by the Trusted 271 Computing Group's Trusted Network Communications (TNC) workgroup. 272 The TNC and NEA architectures are interoperable and many components 273 are equivalent. 275 1.2. Conventions Used in This Document 277 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 278 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 279 "OPTIONAL" in this document are to be interpreted as described in BCP 280 14 [RFC2119] [RFC8174] when, and only when, they appear in all 281 capitals, as shown here. 283 1.3. Definitions 285 This section defines terms with special meaning within this document. 287 SWIMA-PC - A NEA Posture Collector (PC) that interprets SWIMA 288 Attributes sent by SWIMA-PVs and which conforms to this 289 specification. Note that such a posture collector might also support 290 other PA-TNC exchanges beyond those defined herein. 292 SWIMA-PV - A NEA Posture Validator (PV) that interprets SWIMA 293 Attributes sent by SWIMA-PCs and which conforms to this 294 specification. Note that such a posture verifier might also support 295 other PA-TNC exchanges beyond those defined herein. 297 SWIMA Attribute - This is a PA-TNC attribute (as defined in RFC 5792 298 [RFC5792] extension as defined in this specification. 300 Endpoint's Software Inventory Evidence Collection - The set of 301 information regarding the set of software installed on an endpoint. 302 An endpoint's software inventory evidence collection might include 303 information created by or derived from multiple sources, including 304 but not limited to SWID tag files deposited on the file system during 305 software installation, information generated by software discovery 306 tools, and information dynamically generated by a software or package 307 management system on an endpoint. 309 Software Inventory Evidence Record - The endpoint's Software 310 Inventory Evidence Collection is composed of "records". Each record 311 corresponds to one installed instance of a particular software 312 product as reported by some data source. It is possible for a single 313 installed instance to have multiple software inventory evidence 314 records in an endpoint's Software Inventory Evidence Collection - 315 this can happen if multiple sources all report the same software 316 installation instance. 318 Software Identifier - A string associated with a specific version of 319 a specific software product. These identifiers are derived from the 320 records used to describe software products. SWIMA does not limit the 321 formats of these records, nor does it enforce that the same format be 322 populated the same way by all data sources. As such, while each 323 software identifier uniquely identifies a specific software product, 324 the same software product might be associated with multiple software 325 identifiers reflecting differences between different data sources and 326 supported record formats. 328 2. Background 330 2.1. Supported Use Cases 332 This section describes the use cases supported by this specification. 333 The primary use of exchanging software inventory information over the 334 PA-TNC interface is to enable a challenger (e.g., NEA Server) to 335 obtain inventory evidence about some system in a way that conforms to 336 NEA procedures and expressed using a standard format. Collected 337 software information can support a range of security activities 338 including determining whether an endpoint is permitted to connect to 339 the enterprise, determining which endpoints contain software that 340 requires patching, and similar activities. 342 2.1.1. Use Software Inventory as an Access Control Factor 344 Some enterprises might define security policies that require 345 connected endpoints to have certain pieces of security software 346 installed. By contrast, some security policies might prevent access 347 to resources by endpoints that have certain prohibited pieces of 348 software installed, since such applications might pose a security 349 risk. To support such policies, the NEA Server needs to collect 350 software inventory evidence from a target endpoint that is seeking to 351 initiate or continue connectivity to the enterprise resource. 353 Based on this specification, the SWIMA-PC can provide a complete or 354 partial inventory to the SWIMA-PV as required to determine policy 355 compliance. The SWIMA-PV can then use this as evidence of compliance 356 or non-compliance to make a policy-based access decision. 358 2.1.2. Central Stores of Up-to-Date Endpoint Software Inventory Data 360 Many tools use information about an endpoint's software inventory to 361 monitor and enforce the security of a network. For example, a 362 software patching tool needs to determine if there is out-of-date 363 software installed that needs to be updated. A vulnerability 364 management tool needs to identify endpoints with known vulnerable 365 software installed (patched or otherwise) to gauge an endpoint's 366 relative exposure to attack. A license management tool needs to 367 verify that all installed software within the enterprise is accounted 368 for. A central repository representing an up-to-date understanding 369 of each endpoint's software inventory facilitates these activities. 370 Multiple tools can share such a repository ensuring that software 371 inventory information is collected more frequently and efficiently, 372 leading to a more complete and consistent understanding of installed 373 software state as compared to each tool collecting the same inventory 374 information from endpoints individually. 376 This specification supports these activities through a number of 377 mechanisms. As noted above, a SWIMA-PC can provide a complete list 378 of software present in an endpoint's Software Inventory Evidence 379 Collection to the SWIMA-PV, which can then pass this information on 380 to a central repository, such as a Configuration Management Database 381 (CMDB) or similar application. In addition, SWIMA-PCs are required 382 to be able to monitor for changes to an endpoint's Software Inventory 383 Evidence Collection in near real-time and immediately push reports of 384 detected changes to the SWIMA-PV. Thus, any central repository fed 385 by a SWIMA-PV receiving inventory information can be updated quickly 386 after a change occurs. Keeping a central repository synchronized 387 with current software inventory information in this way allows tools 388 to make efficient decisions based on up-to-date, consistent 389 information. 391 2.1.3. PA-TNC Use Cases 393 SWIMA is intended to operate over the PA-TNC interface and, as such, 394 are intended to meet the use cases set out in the PA-TNC 395 specification. 397 2.2. Non-supported Use Cases 399 Some use cases not covered by this specification include: 401 o Addressing how the endpoint's Software Inventory Evidence 402 Collection is populated. In particular, NEA components are not 403 expected to perform software discovery activities beyond compiling 404 information in an endpoint's Software Inventory Evidence 405 Collection. This collection might come from multiple sources on 406 the endpoint (e.g., information generated dynamically by package 407 management tools or discovery tools, as well as SWID tag files 408 discovered on the file system). While an enterprise might make 409 use of software discovery capabilities to identify installed 410 software, such capabilities are outside the scope of this 411 specification. 413 o Converting inventory information expressed in a proprietary format 414 into formats used in the attributes described in this 415 specification. Instead, this specification focuses exclusively on 416 defining interfaces for the transportation of software information 417 expecting that reporting tools will converge around some set of 418 standardized formats for this information. 420 o Mechanisms for a posture validator to request a specific list of 421 software information based on arbitrary software properties. For 422 example, requesting only information about software from a 423 particular vendor is not supported. After the endpoint's Software 424 Inventory Evidence Collection has been copied to some central 425 location, such as the CMDB, processes there can perform queries 426 based on any criteria present in the collected information, but 427 this specification does not address using such queries to 428 constrain the initial collection of this information from the 429 endpoint. 431 o Use of properties of certain sources of software information that 432 might facilitate local tests (i.e., on the endpoint) of endpoint 433 state. For example, the optional package_footprint field of an 434 ISO SWID tag can contain a list of files and hash values 435 associated with the software indicated by the tag. Tools on the 436 endpoint can use the values in this field to test for the presence 437 of the indicated files. Successful evaluation of such tests leads 438 to greater assurance that the indicated software is present on the 439 endpoint. Currently, most SWID tag creators do not provide values 440 for tag fields that support local testing. For this reason, the 441 added complexity of supporting endpoint testing using these fields 442 is out of scope for this specification, but may be considered in a 443 future version. 445 2.3. Specification Requirements 447 Below are the requirements that the SWIMA specification is required 448 to meet in order to successfully play its role in the NEA 449 architecture. 451 Efficient: The NEA architecture enables delay of network access 452 until the endpoint is determined not to pose a security threat to 453 the network based on its asserted integrity information. To 454 minimize user frustration, SWIMA ought to minimize overhead delays 455 and make PA-TNC communications as rapid and efficient as possible. 457 Scalable: SWIMA needs to be usable in enterprises that contain tens 458 of thousands of endpoints or more. As such, it needs to allow a 459 security tools to make decisions based on up-to-date information 460 about an endpoint's software inventory without creating an 461 excessive burden on the enterprise's network. 463 Support precise and complete historical reporting: This 464 specification outlines capabilities that support real-time 465 understanding of the state of endpoint in a network in a way that 466 can be used by other tools. One means of facilitating such an 467 outcome is for a CMDB to be able to contain information about all 468 endpoints connected to the enterprise for all points in time 469 between the endpoint's first connection and the present. In such 470 a scenario, it is necessary that any PC be able to report any 471 changes to its software inventory evidence collection in near 472 real-time while connected and, upon reconnection to the 473 enterprise, be able to update the NEA Server (and through it the 474 CMDB) with regard to the state of its software inventory evidence 475 collection throughout the entire interval when it was not 476 connected. 478 2.4. Non-Requirements 480 There are certain requirements that the SWIMA specification 481 explicitly is not required to meet. This list is not exhaustive. 483 End to End Confidentiality: This specification does not define a 484 mechanism for confidentiality, nor is this property automatically 485 provided by using the PA-TNC interface. In the NEA architecture, 486 confidentiality is generally provided by the underlying transport 487 protocols, such as the PT Binding to TLS [RFC6876] or PT-EAP 488 Posture Transport for Tunneled EAP Methods [RFC7171] - see 489 Section 9 for more information on related standards. Should users 490 wish to protect the confidentiality of assessment instructions or 491 results, then an appropriate transport needs to be used. 493 2.5. Assumptions 495 The Posture Broker Client and Posture Broker Server are assumed to 496 provide reliable delivery for PA-TNC messages and attributes sent 497 between the SWIMA-PCs and the SWIMA-PVs. Reliable delivery means 498 that either a message is delivered or the sender is made aware of the 499 delivery failure. In the event that reliable delivery cannot be 500 provided, the Posture Collector or Posture Validator is expected to 501 terminate the connection. 503 2.6. Non-Assumptions 505 This specification explicitly does not assume that software inventory 506 information exchanges reflect the software installation state of the 507 endpoint. This specification does not attempt to detect when the 508 endpoint is providing false information, either through malice or 509 error, but instead focuses on correctly and reliably providing the 510 reported Software Inventory Evidence Collection to the NEA Server. 511 Tools that employ the SWIMA standard can include methods to help 512 verify the accuracy of reports, but how those tools do so is beyond 513 the scope of this specification. 515 Similarly, this specification makes no assumption about the 516 completeness of the Software Inventory Evidence Collection's coverage 517 of the total set of software installed on the endpoint. It is 518 possible, and even likely, that some installed software is not 519 represented by a record in an endpoints Software Inventory Evidence 520 Collection. Instead, SWIMA ensures that what does get reported is 521 reported consistently and that the software products that are 522 reported can be reliably tracked. 524 See Section 7 for more on this security consideration. 526 3. System Requirements 528 The SWIMA specification facilitates the exchange of software 529 inventory and event information. Specifically, each application 530 supporting SWIMA includes a component known as the SWIMA-PC that 531 receives messages sent with the SWIMA Attributes component type. The 532 SWIMA-PC is also responsible for sending appropriate SWIMA Attributes 533 back to the SWIMA-PV in response. This section outlines what 534 software inventories and events are and the requirements on SWIMA-PCs 535 and SWIMA-PVs in order to support the stated use cases of this 536 specification. 538 3.1. Data Sources 540 The records in an endpoint's software inventory evidence collection 541 come from one or more "sources". A source represents one collection 542 of software inventory information about the endpoint. Examples of 543 sources include, but are not limited to, ISO SWID tags deposited on 544 the filesystem and collected therefrom, information derived from 545 package managers (e.g., RPM or YUM), and the output of software 546 inventory scanning tools. 548 There is no expectation that any one source of inventory information 549 will have either perfect or complete software inventory information. 550 For this reason, this specification supports the simultaneous use of 551 multiple sources of software inventory information. Each source 552 might have its own "sphere of expertise" and report the software 553 within that sphere. For example, a package manager would have 554 excellent understanding of the software that it managed, but would 555 not necessarily have any information about software installed via 556 other means. 558 A SWIMA-PC is not required to utilize every possible source of 559 software information on its endpoint. Some SWIMA-PCs might be 560 explicitly tied only to one or a handful of software inventory 561 sources, or it could be designed to dynamically accommodate new 562 sources. For all software inventory evidence sources that a 563 particular SWIMA-PC supports, it MUST completely support all 564 requirements of this specification with regard to those sources. A 565 potential source that cannot support some set of required 566 functionality (e.g., it is unable to monitor the software it reports 567 for change events, as discussed in Section 3.6) MUST NOT be used as a 568 source of endpoint software inventory information, even if it could 569 provide some information. In other words, a source either supports 570 full functionality as described in this specification, or it cannot 571 be used at all. 573 When sending information about installed software the SWIMA-PC MUST 574 include the complete set of relevant data from all supported sources 575 of software inventory evidence. In other words, sources need to be 576 used consistently. This is because, if a particular source is 577 included in an initial inventory, but excluded from a later 578 inventory, the SWIMA-PV receiving this information might reasonably 579 conclude that the software reported by that source was no longer 580 installed on the endpoint. As such, it is important that all 581 supported sources be used every time the SWIMA-PC provides 582 information to a SWIMA-PV. 584 Note that, if a SWIMA-PC collects data from multiple sources, it is 585 possible that some software products might be "double counted". This 586 can happen if both sources of inventory evidence provide a record for 587 a single installation of a software product. When a SWIMA-PC reports 588 information or records events from multiple inventory evidence 589 sources, it MUST use the information those sources provide, rather 590 than attempting to perform some form of reduction. In other words, 591 if multiple sources report records corresponding to a single 592 installation of a software product, all such records from each source 593 are required to be part of the SWIMA-PC's processing even if this 594 might lead to multiple reporting, and the SWIMA-PC is not to ignore 595 some records to avoid such multiple reporting. 597 All inventory records reported by a SWIMA-PC include a Source 598 Identifier linking them to a particular source. Source Identifiers 599 are discussed more in Section 3.4.5. 601 3.2. Data Models 603 SWIMA conveys records about software presence from a SWIMA-PC to a 604 SWIMA-PV. SWIMA does not manage the actual generation or collection 605 of such records on the endpoint. As a result, information available 606 to SWIMA-PCs might come in a variety of formats, and a SWIMA-PC could 607 have little control over the format of the data made available to it. 608 Because of this, SWIMA places no constraints on the format of these 609 generated records and supports an open set of record formats by which 610 installed software instances can be described. The following terms 611 are used in this document: 613 Data model - The format used to structure data within a given record. 614 SWIMA does not constrain the data models it conveys. 616 Record - A populated instance of some data model that describes a 617 software product. 619 Do not confuse the "data model" described here with the structure of 620 the SWIMA messages and attributes used to convey information between 621 SWIMA-PVs and PCs. The SWIMA specification dictates the structure of 622 its messages and attributes. Some attributes, however, have specific 623 fields used to convey inventory records, and those fields support an 624 extensible list of data models for their values. In other words, 625 SWIMA data models provide an extension point within SWIMA attributes 626 that allows the structure of inventory records to evolve. 628 The data model used to structure software inventory information has 629 very little impact on the behavior of the components defined in this 630 specification. The SWIMA-PV has no dependency on the data model of 631 records conveyed in SWIMA messages. For this reason, it MUST NOT 632 reject a message or respond with a PA-TNC Error due to the data model 633 used to structure records in attributes it receives. Similarly, it 634 MUST NOT reject a message or respond with a PA-TNC Error if a record 635 fails to comply with a stated format, unless that failure prevents 636 correct parsing of the attribute itself. In short, the record bodies 637 are effectively treated as "black boxes" by the SWIMA-PV. (Note that 638 the SWIMA-PV might serve as the front-end of other functionality that 639 does have a dependency on the data model used to structure software 640 information, but any such dependency is beyond the scope of this 641 specification and needs to be addressed outside the behaviors 642 specified in this document. This specification is only concerned 643 with collection and delivery of software inventory information; 644 components that consume and use this information are a separate 645 concern.) 647 The SWIMA-PC does have one functional dependency on the data models 648 used in the software records it delivers, but only insofar as it is 649 required to deterministically create a Software Identifier (described 650 in Section 3.4.1) based on each record it delivers. The SWIMA-PC 651 MUST be able to generate a Software Identifier for each record it 652 delivers, and if the SWIMA-PC cannot do so the record cannot be 653 delivered by the SWIMA-PC. All SWIMA-PCs MUST at least be able to 654 generate Software Identifiers for the data model types specified in 655 Section 6 of this document. A SWIMA-PC MAY include the ability to 656 generate Software Identifiers for other data model types, and thus be 657 able to support them as well. 659 3.3. Basic Attribute Exchange 661 In the most basic exchange supported by this specification, a SWIMA- 662 PV sends a request to the SWIMA-PC requesting some type of 663 information about the endpoint's software inventory. This simple 664 exchange is shown in Figure 2. 666 +-------------+ +--------------+ 667 | SWIMA-PC | | SWIMA-PV | Time 668 +-------------+ +--------------+ | 669 | | | 670 |<------------SWIMA Request---------------| | 671 | | | 672 |-------------SWIMA Response------------->| | 673 | | V 675 Figure 2: Basic SWIMA Attribute Exchange 677 Upon receiving such a SWIMA Request from the SWIMA-PV, the SWIMA-PC 678 is expected to collect all the relevant software inventory 679 information from the endpoint's software evidence collection and 680 place it within its response attribute. 682 SWIMA-PVs MUST discard without error any SWIMA Response attributes 683 that they receive for which they do not know the SWIMA Request 684 parameters that led to this SWIMA Response. This is due to the fact 685 that the SWIMA Request includes parameters that control the nature of 686 the response (as will be described in the following sections) and 687 without knowing those parameters the SWIMA Response cannot be 688 reliably interpreted. Most often receiving an unsolicited SWIMA 689 Response attribute happens when a NEA Server has multiple SWIMA-PVs; 690 one SWIMA-PV sends a SWIMA Request but, unless exclusive delivery is 691 set by the sender and honored by the recipient, both SWIMA-PVs 692 receive copies of the resulting SWIMA Response. In this case, the 693 SWIMA-PV that didn't send the SWIMA Request would lack the context 694 necessary to correctly interpret the SWIMA Response it received and 695 would simply discard it. Note, however, that proprietary measures 696 might allow a SWIMA-PV to discover the SWIMA Request parameters for a 697 SWIMA Response even if that SWIMA-PV did not send the given SWIMA 698 Request. As such, there is no blanket requirement for a SWIMA-PV to 699 discard all SWIMA Responses to SWIMA Request the SWIMA-PV did not 700 generate itself, only that SWIMA-PVs are required to discard SWIMA 701 Responses for which they cannot get the necessary context to 702 interpret. 704 In the case that it is possible to do so, the SWIMA-PC SHOULD send 705 its SWIMA Response attribute to the SWIMA-PV that requested it using 706 exclusive delivery as described in section 4.5 of RFC 5793 (PB-TNC) 707 [RFC5793]. Exclusive delivery requests that only the sender of the 708 SWIMA Request receives the resulting SWIMA Response. Note, however, 709 that PB-TNC does not require the recipient to honor the exclusive 710 delivery flag in messages that it receives, so setting the flag 711 cannot be guaranteed to prevent a SWIMA-PV from receiving unsolicited 712 SWIMA Responses. 714 All numeric values sent in SWIMA messages are sent in network (big 715 endian) byte order. 717 3.4. Core Software Reporting Information 719 Different parameters in the SWIMA Request can influence what 720 information is returned in the SWIMA Response. However, while each 721 SWIMA Response provides different additional information about this 722 installed software, they all share a common set of fields that 723 support reliable software identification on an endpoint. These 724 fields include: Software Identifiers, the Data Model Type, Record 725 Identifiers, Software Locators, and Source Identifiers. These fields 726 are present for each reported piece of software in each type of SWIMA 727 Response. The following sections examine these information types in 728 more detail. 730 3.4.1. Software Identifiers 732 A Software Identifier uniquely identifies a specific version of a 733 specific software product. The SWIMA specification does not dictate 734 the structure of a Software Identifier (beyond stating that it is a 735 string) or define how it is created. Instead, each data model 736 described in the Software Data Model IANA table (Section 10.4) 737 includes its own rules for how a Software Identifier is created based 738 on a record in the Endpoint's Software Inventory Evidence Collection 739 expressed in that data model. Other data models will have their own 740 procedures for the creation of associated Software Identifiers. 741 Within the SWIMA specification, the Software Identifier is simply an 742 opaque string and there is never any need to unpack any information 743 that might be part of that identifier. 745 A Software Identifier is a fraction of the size of the inventory 746 record from which it is derived. For some combinations of data 747 models and sources, the full record might never be necessary as the 748 identifier can be directly correlated to the contents of the full 749 record. This is possible with authoritative SWID tags, since these 750 tags always have the same contents and thus a Software Identifier 751 derived from these tags can be used as a lookup to a local copy of 752 the full tag. For other combinations of source and data model, a 753 server might not be able to determine the specific software product 754 and version associated with the identifier without requesting 755 delivery of the full record. However, even in those cases, 756 downstream consumers of this information might never need the full 757 record as long as the Software Identifiers they receive can be 758 tracked reliably. A SWIMA-PV can use Software Identifiers to track 759 the presence of specific software products on an endpoint over time 760 in a bandwidth-efficient manner. 762 There are two important limitations of Software Identifiers to keep 763 in mind: 765 1. The identifiers do not necessarily change when the associated 766 record changes. In some situations, a record in the endpoint's 767 Software Inventory Evidence Collection will change due to new 768 information becoming available or in order to correct prior 769 errors in that information. Such changes might or might not 770 result in changes to the Software Identifier, depending on the 771 nature of the changes and the rules governing how Software 772 Identifiers are derived from records of the appropriate data 773 model. 775 2. It is possible that a single software product is installed on a 776 single endpoint multiple times. If both of these installation 777 instances are reported by the same source using the same data 778 format, then this can result in identical Software Identifiers 779 for each installation instances. In other words, Software 780 Identifiers might not uniquely identify installation instances; 781 they just are intended to uniquely identify software products 782 (which might have more than one installation instance). Instead, 783 to reliably distinguish between multiple instances of a single 784 software product, one needs to make use of Record Identifiers, 785 described in Section 3.4.3. 787 3.4.2. Data Model Type 789 The Data Model Type consists of two fields: the Data Model Type PEN 790 and the Data Model Type. The combination of these fields is used to 791 identify the type of data model of the associated software inventory 792 record. The data model is significant not only because it informs 793 the recipient of the data model of the associated record, but because 794 the process for generation of the Software Identifier for the record 795 depends on the record's data model. Clearly identifying the type of 796 data model from which the Software Identifier was derived thus 797 provides useful context for that value. 799 The PEN (or Private Enterprise Number) identifies the organization 800 that assigns meaning to the Data Model Type field value. PENs are 801 managed by IANA in the Private Enterprise Numbers registry. PENs 802 allow vendors to designate their own set of data models for software 803 inventory description. IANA reserves the PEN of 0x000000. Data 804 Model Types associated with this PEN are defined in the Software Data 805 Model IANA table, created in Section 10.4 of this specification. 806 Note that this IANA table reserves all values greater than or equal 807 to 0xC0 (192) for enterprise use. This means that local enterprises 808 can use custom data formats and indicate them with the IANA PEN and a 809 Data Model Type value between 0xC0 and 0XFF, inclusive. Those 810 enterprises are responsible for configuring their SWIMA-PCs to 811 correctly report those custom data models. 813 3.4.3. Record Identifiers 815 A Record Identifier is a 4-byte unsigned integer generated by the 816 SWIMA-PC that is uniquely associated with a specific record within 817 the Endpoint's Software Inventory Evidence Collection. The SWIMA-PC 818 MUST assign a unique identifier to each record when it is added to 819 the Endpoint's Software Inventory Evidence Collection. The Record 820 Identifier SHOULD remain unchanged if that record is modified. 821 (However, it is recognized that, in some circumstances, record 822 modification might be hard to distinguish from record deletion 823 followed by creation of a new record. For this reason, retaining a 824 constant Record Identifier across record modification is recommended 825 but not required.) The SWIMA-PC might wish to assign Record 826 Identifiers sequentially, but any scheme is acceptable provided that 827 no two records receive the same identifier. 829 Servers can use Record Identifiers to distinguish between multiple 830 instances of a single software product installed on an endpoint. 831 Since each installation instance of a software product is associated 832 with a separate record, servers can use the record identifier to 833 distinguish between instances. For example, if an event is reported 834 (as described in Section 3.7), the record identifier will allow the 835 server to discern which instance of a software product is involved. 837 3.4.4. Software Locators 839 In addition to the need to identify software products, many use cases 840 of inventory information need to know where software is located on 841 the endpoint. This information might be needed to direct remediation 842 actions or similar processes. For this reason, every reported 843 software product also includes a Software Locator to identify where 844 the software is installed on the endpoint. 846 If the location is not provided directly by the record source the 847 SWIMA-PC is responsible for attempting to determine the location of 848 the software product. The "location" of a product SHOULD be the 849 directory in which the software products' executables are kept. The 850 source and/or SWIMA-PC MUST be consistent in reporting the location 851 of a software product (i.e., assuming a software product has not 852 moved, the SWIMA-PC cannot use one location in one report and a 853 different location for the same software product in another). 855 The location is expressed as a URI string. The string MUST conform 856 to URI syntax requirements. [RFC3986] The URI schema describes the 857 context of the described location. For example, in most cases the 858 location of the installed software product will be expressed in terms 859 of its path in the filesystem. For such locations, the location URI 860 scheme MUST be "file" and the URI MUST conform to the "file" URI 861 scheme standard [RFC8089] including percent-encoding of whitespace 862 and other special characters. It is possible that other schemes 863 could be used to represent other location contexts. Apart from 864 reserving the "file" scheme, this specification does not reserve 865 schemes. When representing software products in other location 866 contexts, tools MUST be consistent in their use of schemes, but the 867 exact string used in those schemes is not normatively defined here. 869 It is possible, that a SWIMA-PC is unable to determine the location 870 of a reported software product. In this case, the SWIMA-PC MUST 871 provide a zero-length Software Locator. 873 3.4.5. Source Identifiers 875 All SWIMA-PCs MUST track the source of each piece of software 876 information they report. Each time a SWIMA-PC gets information to 877 send to a given SWIMA-PV from a new source (from the perspective of 878 that SWIMA-PV), the SWIMA-PC MUST assign that source a Source 879 Identification Number, which is an 8-bit unsigned integer. Each item 880 reported includes the Source Identification Number that provided that 881 information. All information that is provided by that source, MUST 882 be delivered with this same Source Identification Number. This MUST 883 be done for each source used. If the SWIMA-PC ever is unclear as to 884 whether a given source is new or not, it MUST assume that this is a 885 new source and assign it a new Source Identification Number. Source 886 Identification Numbers do not need to be assigned sequentially. 887 SWIMA does not support the presence of more than 256 sources as the 888 chance that a single endpoint will have more than 256 methods of 889 collecting inventory information is vanishingly small. All possible 890 values between 0 and 255 are valid; there are no reserved Source 891 Identification Numbers 893 Source Identification Numbers can help with (although will not 894 completely eliminate) the challenges posed by multiple reporting of a 895 single software instance: since a single source would only report an 896 instance or event once, if multiple reports of a similar instance 897 come from multiple sources, this might be an instance of multiple 898 reporting (although it still might not be so). On the other hand, if 899 multiple instances are reported by a single source, this almost 900 certainly means that there are actually multiple instances that are 901 being legitimately reported. 903 The SWIMA-PC is responsible for tracking associations between Source 904 Identifiers and the given data source. This association MUST remain 905 consistent with regard to a given SWIMA-PV while there is an active 906 PB-TNC session with that SWIMA-PV. The SWIMA-PC MAY have a different 907 Source Identifier association for different SWIMA-PVs. Likewise, the 908 SWIMA-PC MAY change the Source Identifier association for a given 909 SWIMA-PV if the PB-TNC session terminates. However, implementers of 910 SWIMA-PCs will probably find it easier to manage associations by 911 maintaining the same association for all SWIMA-PVs and across 912 multiple sessions. 914 Of special note, events records reported from the SWIMA-PC's event 915 log (discussed in Section 3.7) also need to be sent with their 916 associated data source. The Source Identifier reported with events 917 MUST be the current (i.e., at the time the event is sent) Source 918 Identifier associated with the data source that produced the event, 919 regardless of how long ago that event occurred. Event logs are 920 likely to persist far longer than a single PB-TNC session. SWIMA-PCs 921 MUST ensure that each event can be linked to the appropriate data 922 source, even if the Source Identifiers used when the event was 923 created have since been reassigned. In other words, when sending an 924 event, it needs to be sent with the Source Identifier currently 925 linked to the data source that produced it, regardless of whether a 926 different Source Identifier would have been associated with the event 927 when the event was first created. 929 Note that the Source Identification Number is primarily used to 930 support recognition, rather than identification, of sources. That is 931 to say, a Software Identification Number can tell a recipient that 932 two events were reported by the same source, but will not necessarily 933 help that recipient determine which source was used. Moreover, 934 different SWIMA-PCs will not necessarily use the same Source 935 Identification Numbers for the same sources. SWIMA-PCs MUST track 936 the assignment of Source Identification Numbers to ensure consistent 937 application thereof. SWIMA-PCs MUST also track which Source 938 Identification Numbers have been used with each SWIMA-PV with which 939 they communicate. 941 3.4.6. Using Software and Record Identifiers in SWIMA Attributes 943 A SWIMA Attribute reporting an endpoint's Software Inventory Evidence 944 Collection always contains the Software Identifiers associated with 945 the identified software products. A SWIMA Attribute might or might 946 not also contain copies of software inventory evidence records. The 947 attribute exchange is identical to the diagram shown in Figure 2 948 regardless of whether software inventory evidence records are 949 included. The SWIMA Request attribute indicates whether the response 950 is required to include software inventory evidence records. 951 Excluding software inventory evidence records can reduce the 952 attribute size of the response by multiple orders of magnitude when 953 compared to sending the same inventory with full records. 955 3.5. Targeted Requests 957 Sometimes a SWIMA-PV does not require information about every piece 958 of software on an endpoint but only needs to receive updates about 959 certain software instances. For example, enterprise endpoints might 960 be required to have certain software products installed and to keep 961 these updated. Instead of requesting a complete inventory just to 962 see if these products are present, the SWIMA-PV can make a "targeted 963 request" for the software in question. 965 Targeted requests follow the same attribute exchange described in 966 Figure 2. The SWIMA-PV targets its request by providing one or more 967 Software Identifiers in its SWIMA Request attribute. The SWIMA-PC 968 MUST then limit its response to contain only records that match the 969 indicated Software Identifier(s). This allows the network exchange 970 to exclude information that is not relevant to a given policy 971 question, thus reducing unnecessary bandwidth consumption. The 972 SWIMA-PC's response might or might not include software inventory 973 evidence records, depending on the parameters of the SWIMA Request. 975 Note that targeted requests identify the software relevant to the 976 request only through Software Identifiers. This specification does 977 not support arbitrary, parameterized querying of records. For 978 example, one cannot request all records from a certain software 979 publisher, or all records created by a particular record source. 980 Targeted requests only allow a requestor to request specific software 981 (as identified by their Software Identifiers) and receive a response 982 that is limited to the named software. 984 There is no assumption that a SWIMA-PC will recognize "synonymous 985 records" - that is, records from different sources for the same 986 software. Recall that different sources and data models may use 987 different Software Identifier strings for the same software product. 988 The SWIMA-PC returns only records that match the Software Identifiers 989 in the SWIMA Request, even if there might be other records in the 990 endpoint's Software Inventory Evidence Collection for the same 991 software product. This is necessary because SWIMA-PCs might not have 992 the ability to determine that two Software Identifiers refer to the 993 same product. 995 Targeted requests do not include Record Identifiers or Software 996 Locators. The response to a targeted request MUST include all 997 records associated with the named Software Identifiers, including the 998 case where there are multiple records associated with a single 999 Software Identifier. 1001 SWIMA-PCs MUST accept targeted requests and process them correctly as 1002 described above. SWIMA-PVs MUST be capable of making targeted 1003 requests and processing the responses thereto. 1005 3.6. Monitoring Changes in an Endpoint's Software Inventory Evidence 1006 Collection 1008 The software collection on an endpoint is not static. As software is 1009 installed, uninstalled, patched, or updated, the Software Inventory 1010 Evidence Collection is expected to change to reflect the new software 1011 state on the endpoint. Different record sources might update the 1012 evidence collection at different rates. For example, a package 1013 manager might update its records in the Software Inventory Evidence 1014 Collection immediately whenever it is used to add or remove a 1015 software product. By contrast, sources that perform periodic 1016 examination of the endpoint would likely only update their records in 1017 the Software Inventory Evidence Collection after each examination. 1019 All SWIMA-PCs MUST be able to be able to detect changes to the 1020 Software Inventory Evidence Collection. Specifically, SWIMA-PCs MUST 1021 be able to detect: 1023 o The creation of records 1025 o The deletion of records 1027 o The alteration of records 1029 An "alteration" is anything that modifies the contents of a record 1030 (or would modify it, if the record is dynamically generated on 1031 demand) in any way, regardless of whether the change is functionally 1032 meaningful. 1034 SWIMA-PCs MUST detect such changes to the endpoint's Software 1035 Inventory Evidence Collection in close to real-time (i.e., within 1036 seconds) when the Posture Collector is operating. In addition, in 1037 the case where there is a period during which the SWIMA-PC is not 1038 operating, the SWIMA-PC MUST be able to determine the net change to 1039 the endpoint's Software Inventory Evidence Collection over the period 1040 it was not operational. Specifically, the "net change" represents 1041 the difference between the state of the endpoint's Software Inventory 1042 Evidence Collection when the SWIMA-PC was last operational and 1043 monitoring its state, and the state of the endpoint's software 1044 inventory evidence collection when the SWIMA-PC resumed operation. 1045 Note that a net change might not reflect the total number of change 1046 events over this interval. For example, if a record was altered 1047 three times during a period when the SWIMA-PC was unable to monitor 1048 for changes, the net change of this interval might only note that 1049 there was an alteration to the record, but not how many individual 1050 alteration events occurred. It is sufficient for a SWIMA-PC's 1051 determination of a net change to note that there was a difference 1052 between the earlier and current state rather than enumerating all the 1053 individual events that allowed the current state to be reached. 1055 The SWIMA-PC MUST assign a time to each detected change in the 1056 endpoint's Software Inventory Evidence Collection. These timestamps 1057 correspond to the SWIMA-PC's best understanding as to when the 1058 detected change occurred. For changes to the endpoint's Software 1059 Inventory Evidence Collection that occur while the SWIMA-PC is 1060 operating, the SWIMA-PC ought to be able to assign a time to the 1061 event that is accurate to within a few seconds. For changes to the 1062 endpoint's Software Inventory Evidence Collection that occur while 1063 the SWIMA-PC is not operational, upon becoming operational the SWIMA- 1064 PC needs to make a best guess as to the time of the relevant events 1065 (possibly by looking at timestamps on files), but these values might 1066 be off. In the case of dynamically generated records, the time of 1067 change is the time at which the data from which the records are 1068 generate changes, not the time at which a changed record is 1069 generated. For example, if records are dynamically generated based 1070 on data in an RPM database, the time of change would be when the RPM 1071 database changed. 1073 With regard to deletions of records, the SWIMA-PC needs to detect the 1074 deletion and MUST retain a copy of the full deleted record along with 1075 the associated Record Identifier and Software Locator so that the 1076 record and associated information can be provided to the SWIMA-PV 1077 upon request. This copy of the record MUST be retained for a 1078 reasonable amount of time. Vendors and administrators determine what 1079 "reasonable" means, but a copy of the record SHOULD be retained for 1080 as long as the event recording the deletion of the record remains in 1081 the SWIMA-PC's event log (as described in Section 3.7). This is 1082 recommended because, as long as the event is in the SWIMA-PC's change 1083 logs, the SWIMA-PC might send an event attribute (described in 1084 Section 3.7) that references this record, and a copy of the record is 1085 needed if the SWIMA-PV wants a full copy of the relevant records. In 1086 the case that a SWIMA-PC is called upon to report a deletion event 1087 that is still in the event log but where the record itself is no 1088 longer available, the SWIMA-PC will still return an entry 1089 corresponding to the deletion event, but the field of that entry that 1090 would normally contain the full copy of the record SHOULD be 1091 0-length. 1093 With regard to alterations to a record, SWIMA-PCs MUST detect any 1094 alterations to the contents of a record. Alterations need to be 1095 detected even if they have no functional impact on the record. A 1096 good guideline is that any alteration to a record that might change 1097 the value of a hash taken on the record's contents needs to be 1098 detected by the SWIMA-PC. A SWIMA-PC might be unable to distinguish 1099 modifications to the content of a record from modifications to the 1100 metadata the file system associates with the record. For example, a 1101 SWIMA-PC might use the "last modification" timestamp as an indication 1102 of alteration to a given record, but a record's last modification 1103 time can change for reasons other than modifications to the record 1104 contents. A SWIMA-PC is still considered compliant with this 1105 specification if it also reports metadata change events that do not 1106 change the record itself as alterations to the record. In other 1107 words, while SWIMA-PC authors are encouraged to exclude modifications 1108 that do not affect the bytes within the record, discriminating 1109 between modifications to file contents and changes to file metadata 1110 can be difficult and time consuming on some systems. As such, as 1111 long as the alterations detected by a SWIMA-PC always cover all 1112 modifications to the contents of record, the SWIMA-PC is considered 1113 compliant even if it also registers alterations that do not modify 1114 the contents of a record as well. When recording an alteration to a 1115 record, the SWIMA-PC is only required to note that an alteration 1116 occurred. The SWIMA-PC is not required to note or record how the 1117 record altered, nor is it possible to include such details in SWIMA 1118 Attributes reporting the change to a SWIMA-PV. There is no need to 1119 retain a copy of the original record. 1121 When a record changes it SHOULD retain the same Record Identifier. 1122 The Software Locator might or might not change, depending on whether 1123 the software changed locations during the changes that led to the 1124 record change. A record change MUST retain the same Software 1125 Identifier. This means that any action that changes a software 1126 product (e.g., application of a patch that results in a change to the 1127 product's version) MUST NOT be reflected by a record change but 1128 instead MUST result in the deletion of the old record and the 1129 creation of a new record. This reflects the requirement that a 1130 record in the endpoint's Software Inventory Evidence Collection 1131 correspond directly with an instance of a specific software product. 1133 3.7. Reporting Change Events 1135 As noted in Section 3.6, SWIMA-PCs are required to detect changes to 1136 the endpoints Software Inventory Evidence Collection (creation, 1137 deletion, and alteration) in near real-time while the SWIMA-PC is 1138 operational, and MUST be able to account for any net change to the 1139 endpoint's Software Inventory Evidence Collection that occurs when 1140 the SWIMA-PC is not operational. However, to be of use to the 1141 enterprise, the NEA Server needs to be able to receive these events 1142 and be able to understand how new changes relate to earlier changes. 1143 In SWIMA, this is facilitated by reporting change events. All SWIMA- 1144 PCs MUST be capable of receiving requests for change events and 1145 sending change event attributes. All SWIMA-PVs MUST be capable of 1146 requesting and receiving change event attributes. 1148 3.7.1. Event Identifiers 1150 To be useful, change events need to be correctly ordered. Ordering 1151 of events is facilitated by two pieces of information: an Event 1152 Identifier (EID) value and an EID Epoch value. 1154 An EID is a 4-byte unsigned integer that the SWIMA-PC assigns 1155 sequentially to each observed event (whether detected in real-time or 1156 deduced by looking for net changes over a period of SWIMA-PC 1157 inactivity). All EIDs exist within the context of some "EID Epoch", 1158 which is also represented as a 4-byte unsigned integer. EID Epochs 1159 are used to ensure synchronization between the SWIMA-PC and any 1160 SWIMA-PVs with which it communicates. EID Epoch values MUST be 1161 generated in such a way as to minimize the chance that an EID Epoch 1162 will be reused, even in the case where the SWIMA-PC reverts to an 1163 earlier state. For this reason, sequential EID Epochs are 1164 discouraged, since loss of state could result in value reuse. There 1165 are multiple reasons that a SWIMA-PC might need to deliberately reset 1166 its EID counter, including exhaustion of available EID values, the 1167 need to purge entries from the event log to recover memory, or 1168 corruption of the event log. In all case where a SWIMA-PC needs to 1169 reset its EID counter, a new EID Epoch MUST be selected. 1171 Within an Epoch, EIDs MUST be assigned sequentially, so that if a 1172 particular event is assigned an EID of N, the next observed event is 1173 given an EID of N+1. In some cases, events might occur 1174 simultaneously, or the SWIMA-PC might not otherwise be able to 1175 determine an ordering for events. In these cases, the SWIMA-PC 1176 creates an arbitrary ordering of the events and assigns EIDs 1177 according to this ordering. Two change events MUST NOT ever be 1178 assigned the same EID within the same EID Epoch. No meaningful 1179 comparison can be made between EID values of different Epochs. 1181 The EID value of 0 is reserved and MUST NOT be associated with any 1182 event. Specifically, an EID of 0 in a SWIMA Request attribute 1183 indicates that a SWIMA-PV wants an inventory response rather than an 1184 event response, while an EID of 0 in a SWIMA Response is used to 1185 indicate the initial state of the endpoint's Software Inventory 1186 Evidence Collection prior to the observation of any events. Thus the 1187 very first recorded event in a SWIMA-PC's records within an EID Epoch 1188 MUST be assigned a value of 1. Note that EID and EID Epoch values 1189 are assigned by the SWIMA-PC without regard to whether events are 1190 being reported to one or more SWIMA-PVs. The SWIMA-PC records events 1191 and assigns EIDs during its operation. All SWIMA-PVs that request 1192 event information from the SWIMA-PC will have those requests served 1193 from the same event records and thus will see the same EIDs and EID 1194 Epochs for the same events. 1196 If a SWIMA-PC uses multiple sources, a SWIMA-PC's assignment of EIDs 1197 MUST reflect the presence and order of all events on the endpoint (at 1198 least for supported sources) regardless of the source. This means 1199 that if source A experiences an event, and then source B experiences 1200 two events, and then source A experiences another two events, the 1201 SWIMA-PC is required to capture five events with consecutive EID 1202 values reflecting the order in which the events occur. 1204 The SWIMA-PC MUST ensure there is no coverage gap (i.e., change 1205 events that are not recorded in the SWIMA-PC's records) in its change 1206 event records. This is necessary because a coverage gap might give a 1207 SWIMA-PV a false impression of the endpoint's state. For example, if 1208 a SWIMA-PV saw an event indicating that a particular record had been 1209 added to the endpoint's software inventory evidence collection, and 1210 saw no subsequent events indicating that record had been deleted, it 1211 might reasonably assume that this record was still present and thus 1212 that the indicated software was still installed (assuming the Epoch 1213 has not changed). If there is a coverage gap in the SWIMA-PC's event 1214 records, however, this assumption could be false. For this reason, 1215 the SWIMA-PC's event records MUST NOT contain gaps. In the case 1216 where there are periods where it is possible that changes occurred 1217 without the SWIMA-PC detecting or recording them, the SWIMA-PC MUST 1218 either compute a net change and update its event records 1219 appropriately, or pick a new EID Epoch to indicate a discontinuity 1220 with previous event records. 1222 Within a given Epoch, once a particular event has been assigned an 1223 EID, this association MUST NOT be changed. That is, within an Epoch, 1224 once an EID is assigned to an event, that EID cannot be reassigned to 1225 a different event, and the event cannot be assigned a different EID. 1226 When the SWIMA-PC's Epoch changes, all of these associations between 1227 EIDs and events are cancelled, and EID values once again become free 1228 for assignment. 1230 3.7.2. Core Event Tracking Information 1232 Whether reporting events or full inventories it is important to know 1233 how the reported information fits into the overall timeline of change 1234 events. This is why all SWIMA Response attributes include fields to 1235 place that response within the sequence of detected events. 1236 Specifically, all SWIMA Responses include a Last EID and EID Epoch 1237 field. The EID Epoch field identifies the EID Epoch in which the 1238 SWIMA Response was sent. If the SWIMA Response is reporting events, 1239 all reported events occurred within the named EID Epoch. The Last 1240 EID (which is also always from the named EID Epoch) indicates the EID 1241 of the last recorded change event at the time that the SWIMA Response 1242 was sent. These two fields allow any response to be placed in the 1243 context of the complete set of detected change events within a given 1244 EID Epoch. 1246 3.7.3. Updating Inventory Knowledge Based on Events 1248 Modern endpoints can have hundreds of software products installed, 1249 most of which are unlikely to change from one day to the next. As 1250 such, instead of exchanging a complete list of an endpoint's 1251 inventory on a regular basis, one might wish to only identify changes 1252 since some earlier known state of this inventory. This is readily 1253 facilitated by the use of EIDs to place change events in a context 1254 relative to earlier state. 1256 As noted above, every SWIMA Response sent by a SWIMA-PC to a SWIMA-PV 1257 (as described in Section 3.3 through Section 3.5) includes the EID 1258 Epoch and EID of the last event recorded prior to that response being 1259 compiled. This allows the SWIMA-PV to place all subsequently 1260 received event records in context relative to this SWIMA Response 1261 attribute (since the EIDs represent a total ordering of all changes 1262 to the endpoint's software inventory evidence collection). 1263 Specifically, a SWIMA-PV (or, more likely, a database that collects 1264 and records its findings) can record an endpoint's full inventory and 1265 also the EID and Epoch of the most recent event reflected at the time 1266 of that inventory. From that point on, if change events are 1267 observed, the attribute describing these events indicates the nature 1268 of the change, the affected records, and the order in which these 1269 events occurred (as indicated by the sequential EIDs). Using this 1270 information, any remote record of the endpoint's Software Inventory 1271 Evidence Collection can be updated appropriately. 1273 3.7.4. Using Event Records in SWIMA Attributes 1275 A SWIMA-PV MUST be able to request a list of event records instead of 1276 an inventory. The attribute flow in such an exchange looks the same 1277 as the basic flow shown in Figure 2. The only difference is that, in 1278 the SWIMA Request attribute, the SWIMA-PV provides an EID other than 1279 0. (A value of 0 in these fields represents a request for an 1280 inventory.) When the SWIMA-PC receives such a request, instead of 1281 identifying records from the endpoint's Software Inventory Evidence 1282 Collection, it consults its list of detected changes. The SWIMA-PC 1283 MUST add an event record to the SWIMA Response attribute for each 1284 recorded change event with an EID greater than or equal to the EID in 1285 the SWIMA Request attribute (although targeting of requests, as 1286 described in the next paragraph, might limit this list). A list of 1287 event records MUST only contain events with EIDs that all come from 1288 the current Epoch. 1290 SWIMA-PVs can target requests for event records by including one or 1291 more Software Identifiers, as described in Section 3.5, in the SWIMA 1292 Request that requests an event record list. A targeted request for 1293 event records is used to indicate that only events affecting software 1294 that matches one of the provided Software Identifiers are to be 1295 returned. Specifically, in response to a targeted request for event 1296 records, the SWIMA-PC MUST exclude any event records that are less 1297 than the indicated EID (within the current EID Epoch) and exclude any 1298 event records where the affected software does not match one of the 1299 provided Software Identifiers. This might mean that the resulting 1300 list of event records sent in the response attribute does not provide 1301 a continuous sequence of EIDs. Both SWIMA-PCs and SWIMA-PVs MUST 1302 support targeted request for event records. 1304 3.7.5. Partial and Complete Lists of Event Records in SWIMA Attributes 1306 Over time, a SWIMA-PC might record a large number of change events. 1307 If a SWIMA-PV requests all change events covering a large period of 1308 time, the resulting SWIMA Response attribute might be extremely 1309 large, especially if the SWIMA-PV requests inclusion of software 1310 inventory evidence records in the response. In the case that the 1311 resulting attribute is too large to send (either because it exceeds 1312 the 4GB attribute size limit imposed by the PA-TNC specification, or 1313 because it exceeds some smaller size limit imposed on the SWIMA-PC) 1314 the SWIMA-PC MAY send a partial list of event records back to the 1315 SWIMA-PV. 1317 Generation of a partial list of events in a SWIMA Response attribute 1318 requires the SWIMA-PC to identify a "consulted range" of EIDs. A 1319 consulted range is the set of event records that are examined for 1320 inclusion in the SWIMA Response attribute and that are included in 1321 that attribute if applicable. Recall that, if a SWIMA Request is 1322 targeted, only event records that involve the indicated software 1323 would be applicable. (See Section 3.5 for more on Targeted Request.) 1324 If a request is not targeted, all event records in the considered 1325 range are applicable and included in the SWIMA Response attribute. 1327 The lower bound of the consulted range MUST be the EID provided in 1328 the SWIMA Request. (Recall that a SWIMA Request indicates a request 1329 for event records by providing a non-0 EID value in the SWIMA 1330 Request. See Section 3.7.4.) The upper bound of the consulted range 1331 is the EID of the latest event record (as ordered by EID values) that 1332 is included in the SWIMA Response attribute if it is applicable to 1333 the request. The EID of this last event record is called the "Last 1334 Consulted EID". The SWIMA-PC chooses this Last Consulted EID based 1335 on the size of the event record list it is willing to provide to the 1336 SWIMA-PV. 1338 A partial result list MUST include all applicable event records 1339 within the consulted range. This means that for any applicable event 1340 record (i.e., any event record in an un-targeted request, or any 1341 event record associated with software matching a requested Software 1342 Identifier in a targeted request) whose EID is greater than or equal 1343 to the EID provided in the SWIMA Request and whose EID is less than 1344 or equal to the Last Consulted EID, that event record MUST be 1345 included in the SWIMA Response conveying this partial list of event 1346 records. This ensures that every partial list of event records is 1347 always complete within its indicated range. Remember that, for 1348 targeted requests, "complete" doesn't mean that all EIDs between the 1349 range endpoints are present, but only that every matching EID between 1350 the range endpoints is included. 1352 All SWIMA Response attributes that convey event records include a 1353 Last Consulted EID field. This is in addition to the EID Epoch and 1354 Last EID fields that are present in all SWIMA Responses. Note that, 1355 if responding to a targeted SWIMA Request, the SWIMA Response 1356 attribute might not contain the event record whose EID matches the 1357 Last Consulted EID value. For example, the last consulted EID record 1358 might have been deemed inapplicable because it did not match the 1359 specified list of Software Identifiers in the SWIMA Request. 1361 If a SWIMA-PV receives a SWIMA Response attribute where the Last EID 1362 and Last Consulted EID fields are identical, the SWIMA-PV knows that 1363 it has received a result list that is complete, given the parameters 1364 of the request, up to the present time. 1366 On the other hand, if the Last EID is greater than the Last Consulted 1367 EID, the SWIMA-PV has received a partial result list. (The Last 1368 Consulted EID MUST NOT exceed the Last EID.) In this case, if the 1369 SWIMA-PV wishes to try to collect the rest of the partially delivered 1370 result list it then sends a new SWIMA Request whose EID is one 1371 greater than the Last Consulted EID in the preceding response. Doing 1372 this causes the SWIMA-PC to generate another SWIMA Response attribute 1373 containing event records where the earliest reported event record is 1374 the one immediately after the event record with the Last Consulted 1375 EID (since EIDs are assigned sequentially). By repeating this 1376 process until it receives a SWIMA Response where the Last EID and 1377 Last Consulted EID are equal, the SWIMA-PV is able to collect all 1378 event records over a given range, even if the complete set of event 1379 records would be too large to deliver via a single attribute. 1381 Implementers need to be aware that a SWIMA Request might specify an 1382 EID that is greater than the EID of the last event recorded by a 1383 SWIMA-PC. In accordance with the behaviors described in 1384 Section 3.7.4, a SWIMA-PC MUST respond to such a request with a SWIMA 1385 Response attribute that contains zero event records. This is because 1386 the SWIMA-PC has recorded no event records with EIDs greater than or 1387 equal to the EID in the SWIMA Request. In such a case, the Last 1388 Consulted EID field MUST be set to the same value as the Last EID 1389 field in this SWIMA Response attribute. This case is called out 1390 because the consulted range on a SWIMA-PC in such a situation is a 1391 negative range, where the "first" EID in the range (provided in the 1392 SWIMA Request) is greater than the "last" EID in the range (this 1393 being the EID of the last recorded event on the SWIMA-PC). 1394 Implementers need to ensure that SWIMA-PCs do not experience problems 1395 in such a circumstance. 1397 Note that this specification only supports the returning of partial 1398 results when returning event records. There is no way to return a 1399 partial inventory list under this specification. 1401 3.7.6. Synchronizing Event Identifiers and Epochs 1403 Since EIDs are sequential within an Epoch, if a SWIMA-PV's list of 1404 event records contains gaps in the EID values within a single Epoch, 1405 the SWIMA-PV knows that there are events that have not been accounted 1406 for. The SWIMA-PV can either request a new event list to collect the 1407 missing events or request a full inventory to re-sync its 1408 understanding of the state of the endpoint's Software Inventory 1409 Evidence Collection. In either case, after the SWIMA-PV's record of 1410 the endpoint's Software Inventory Evidence Collection has been 1411 updated, the SWIMA-PV can record the new latest EID value and track 1412 events normally from that point on. 1414 If the SWIMA-PV receives any attribute from a SWIMA-PC where the EID 1415 Epoch differs from the EID Epoch that was used previously, then 1416 SWIMA-PV or any entity using this information to track the endpoint's 1417 Software Inventory Evidence Collection knows that there is a 1418 discontinuity in their understanding of the endpoint's state. To 1419 move past this discontinuity and reestablish a current understanding 1420 of the state of the endpoint's Software Inventory Evidence 1421 Collection, the SWIMA-PV needs to receive a full inventory from the 1422 endpoint. The SWIMA-PV cannot be brought in sync with the endpoint's 1423 state through the collection of any set of event records in this 1424 situation. This is because it is not possible to account for all 1425 events on the SWIMA-PC since the previous Epoch was used, because 1426 there is no way to query for EIDs from a previous Epoch. Once the 1427 SWIMA-PV has received a full inventory for the new Epoch, the SWIMA- 1428 PV records the latest EID reported in this new Epoch and can track 1429 further events normally. 1431 A SWIMA-PC MUST NOT report events with EIDs from any Epoch other than 1432 the current EID Epoch. The SWIMA-PC MAY choose to purge all event 1433 records from a previous Epoch from memory after an Epoch change. 1434 Alternately, the SWIMA-PC MAY choose to retain some event records 1435 from a previous EID Epoch and assign them new EIDs in the current 1436 Epoch. However, in the case where a SWIMA-PC chooses the latter 1437 option it MUST ensure that the order of events according to their 1438 EIDs is unchanged and that there is no coverage gap between the first 1439 retained event recorded during the previous Epoch (now reassigned 1440 with an EID in the current Epoch) and the first event recorded during 1441 the current Epoch. In particular, the SWIMA-PC MUST ensure that all 1442 change events that occurred after the last recorded event from the 1443 previous Epoch are known and recorded. (This might not be possible 1444 if the Epoch change is due to state corruption on the SWIMA-PC.) A 1445 SWIMA-PC might choose to reassign EIDs to records from a preceding 1446 Epoch to create a "sliding window" of events, where each Epoch change 1447 represents a shift in the window of available events. 1449 In the case where a SWIMA-PC suffers a crash and loses track of its 1450 current EID Epoch or current EID, then it MUST generate a new EID 1451 Epoch value and begin assigning EIDs within that Epoch. In this 1452 case, the SWIMA-PC MUST purge all event records from before the crash 1453 as it cannot ensure that there is not a gap between the last of those 1454 records and the next detected event. The process for generating a 1455 new EID Epoch MUST minimize the possibility that the newly generated 1456 EID Epoch is the same as a previously used EID Epoch. 1458 The SWIMA-PV will normally never receive an attribute indicating that 1459 the latest EID is less than the latest EID reported in a previous 1460 attribute within the same EID Epoch. If this occurs, the SWIMA-PC 1461 has suffered an error of some kind, possibly indicative of at least 1462 partial corruption of its event log. In this case, the SWIMA-PV MUST 1463 treat the situation as if there was a change in Epoch and treat any 1464 local copy of the endpoint's Software Inventory Evidence Collection 1465 as out-of-sync until a full inventory can be reported by the SWIMA- 1466 PC. In this case, the SWIMA-PV SHOULD log the occurrence so the 1467 SWIMA-PC can be examined to ensure it is now operating properly. 1469 3.8. Subscriptions 1471 Thus far, all attribute exchanges discussed assume that a SWIMA-PV 1472 sent an SWIMA Request attribute and the SWIMA-PC is providing a 1473 direct response to that request. The SWIMA specification also 1474 supports the ability for a SWIMA-PC to send a SWIMA Response to the 1475 SWIMA-PV in response to observed changes in the endpoint's software 1476 inventory evidence collection, instead of in direct response to a 1477 SWIMA Request. An agreement by a SWIMA-PC to send content when 1478 certain changes are detected to the endpoint's Software Inventory 1479 Evidence Collection is referred to in this specification as a 1480 "subscription", and the SWIMA-PV that receives this content is said 1481 to be "subscribed to" the given SWIMA-PC. All SWIMA-PCs and SWIMA- 1482 PVs MUST support the use of subscriptions. 1484 3.8.1. Establishing Subscriptions 1486 A SWIMA-PV establishes a subscription on a particular SWIMA-PC by 1487 sending a SWIMA Request attribute with the Subscription flag set. 1488 The SWIMA Request attribute is otherwise identical to the SWIMA 1489 Requests discussed in previous sections. Specifically, such a SWIMA 1490 Request might or might not request inclusion of software inventory 1491 evidence records, might or might not be targeted, and might request 1492 change event records or endpoint inventory. Assuming no error is 1493 encountered, a SWIMA-PC MUST send a SWIMA Response attribute in 1494 direct response to this SWIMA Request attribute, just as if the 1495 Subscription flag was not set. As such, the attribute exchange that 1496 establishes a new subscription in a SWIMA-PC has the same flow seen 1497 in the previous attribute exchanges, as depicted in Figure 2. If the 1498 SWIMA-PV does not receive a PA-TNC Error attribute (as described in 1499 Section 3.9 and Section 5.16) in response to their subscription 1500 request, the subscription has been successfully established on the 1501 SWIMA-PC. The SWIMA Request attribute that establishes a new 1502 subscription is referred to as the "establishing request" for that 1503 subscription. 1505 When a subscription is established it is assigned a Subscription ID 1506 value. The Subscription ID is equal to the value of the Request ID 1507 of the establishing request. (For more about Request IDs, see 1508 Section 5.6.) 1510 A SWIMA-PC MUST have the ability to record and support at least 8 1511 simultaneous subscriptions and SHOULD have the ability to support 1512 more than this. These subscriptions might all come from a single 1513 SWIMA-PV, might all be from different SWIMA-PVs, or might be a mix. 1514 In the case that a SWIMA-PC receives a subscription request but is 1515 unable to support an additional subscription, it MUST respond to the 1516 request with a PA-TNC Error attribute of type 1517 SWIMA_SUBSCRIPTION_DENIED_ERROR. 1519 A SWIMA-PV MUST have the ability to record and support at least 256 1520 simultaneous subscriptions and SHOULD have the ability to support 1521 more than this. Any number of these subscriptions might be to the 1522 same SWIMA-PC and any number of these subscriptions might be to 1523 different SWIMA-PCs. 1525 3.8.2. Managing Subscriptions 1527 The SWIMA-PC MUST record each accepted subscription along with the 1528 identity of the party to whom attributes are to be pushed in 1529 compliance with the subscription. This identity includes both the 1530 NEA Server's connection ID and the Posture Validator Identifier from 1531 the PB-PA message that delivered the request. 1533 Likewise, SWIMA-PVs MUST record each accepted subscription for which 1534 they are the subscribing party along with the associated Subscription 1535 ID and the identity of the SWIMA-PC that will be fulfilling the 1536 subscription. The SWIMA-PV needs to retain this information in order 1537 to correctly interpret pushed SWIMA Response attributes sent in 1538 fulfillment of the subscription. The identity of the SWIMA-PC is 1539 given in the Posture Collector Identifier of the PB-PA message header 1540 in all messages from that SWIMA-PC. 1542 3.8.3. Terminating Subscriptions 1544 Subscriptions MAY be terminated at any time by the subscribing SWIMA- 1545 PV by setting the Clear Subscriptions flag in a SWIMA Request. (See 1546 Section 5.7 for more on using this flag.) In the case that a SWIMA 1547 Request with the Clear Subscriptions flag set is received the SWIMA- 1548 PC MUST only clear subscriptions that match both the NEA server 1549 connection ID and the SWIMA-PV ID for this SWIMA Request, and MUST 1550 clear all such subscriptions. 1552 This specification does not give the SWIMA-PV the ability to 1553 terminate subscriptions individually - all subscriptions to the 1554 SWIMA-PV are cleared when the Clear Subscriptions flag is set. 1556 This specification does not give the SWIMA-PC the ability to 1557 unilaterally terminate a subscription. However, if the SWIMA-PC 1558 experiences a fatal error fulfilling a subscription, resulting in 1559 sending a PA-TNC Error attribute of type 1560 SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR, then the subscription whose 1561 fulfillment led to the error MUST be treated as terminated by both 1562 the SWIMA-PC and the SWIMA-PV. Only the subscription experiencing 1563 the error is cancelled and other subscriptions are unaffected. See 1564 Section 3.9 for more on this error condition. 1566 Finally, a subscription is terminated if the connection between the 1567 SWIMA-PC and SWIMA-PV is deleted. This occurs when the connection ID 1568 used in the messages between the SWIMA-PC and the SWIMA-PV becomes 1569 unbound. Loss of this connection ID would prevent the SWIMA-PC from 1570 sending messages in fulfillment of this subscription. As such, loss 1571 of the connection ID necessarily forces subscription termination 1572 between the affected parties. 1574 3.8.4. Subscription Status 1576 A SWIMA-PV can request that a SWIMA-PC report the list of active 1577 subscriptions for which the SWIMA-PV is the subscriber. A SWIMA-PV 1578 can use this to recover lost information about active subscriptions. 1579 A SWIMA-PV can also use this capability to verify that a SWIMA-PC has 1580 not forgotten any of its subscriptions. The latter is especially 1581 useful where a SWIMA-PC does not send any attributes in fulfillment 1582 of a given subscription for a long period of time. The SWIMA-PV can 1583 check the list of active subscriptions on the SWIMA-PC and verify 1584 whether the inactivity is due to a lack of reportable events or due 1585 to the SWIMA-PC forgetting its obligations to fulfill a given 1586 subscription. 1588 A SWIMA-PV requests a list of its subscriptions on a given SWIMA-PC 1589 by sending that SWIMA-PC a Subscription Status Request. The SWIMA-PC 1590 MUST then respond with a Subscription Status Response (or a PA-TNC 1591 Error if an error condition is experienced). The Subscription Status 1592 Response MUST contain one subscription record for each of the active 1593 subscriptions for which the SWIMA-PV is the subscribing party. 1595 3.8.5. Fulfilling Subscriptions 1597 As noted in Section 3.6 SWIMA-PCs are required to automatically 1598 detect changes to an endpoint's Software Inventory Evidence 1599 Collection in near real-time. For every active subscription, the 1600 SWIMA-PC MUST send an attribute to the subscribed SWIMA-PV whenever a 1601 change is detected to relevant records within the endpoint's Software 1602 Inventory Evidence Collection. Such an attribute is said to be sent 1603 "in fulfillment of" the given subscription and any such attribute 1604 MUST include that subscription's Subscription ID. If the 1605 establishing request for that subscription was a targeted request, 1606 then only records that match the Software Identifiers provided in 1607 that establishing request are considered relevant. Otherwise, (i.e., 1608 for non-targeted requests) any record is considered relevant for this 1609 purpose. Figure 3 shows a sample attribute exchange where a 1610 subscription is established and then later attributes are sent from 1611 the SWIMA-PC in fulfillment of the established subscription. 1613 +-------------+ +--------------+ 1614 | SWIMA-PC | | SWIMA-PV | Time 1615 +-------------+ +--------------+ | 1616 | | | 1617 |<----------SWIMA Request-----------| | 1618 | | | 1619 |-----------SWIMA Response--------->| | 1620 | | | 1621 . . . 1622 . . . 1623 . . . 1624 | | | 1625 |----------SWIMA Response---------->| | 1626 | | | 1627 . . . 1628 . . . 1629 . . . 1630 | | | 1631 |----------SWIMA Response---------->| | 1632 | | V 1634 Figure 3: Subscription Establishment and Fulfillment 1636 The contents of an attribute sent in fulfillment of a subscription 1637 depend on the parameters provided in the establishing request for 1638 that subscription. Specifically, the contents of an attribute sent 1639 in fulfillment of a subscription have the same format as would a 1640 direct response to the establishing request. For example, if the 1641 establishing request stipulated a response that contained an event 1642 record list that included software inventory evidence records, all 1643 attributes sent in fulfillment of this subscription will also consist 1644 of event record lists with software inventory evidence records. As 1645 such, all SWIMA Responses displayed in the exchange depicted in 1646 Figure 3 have the same format. A SWIMA Response generated in 1647 fulfillment of an active subscription MUST be a valid SWIMA Response 1648 attribute according to all the rules outlined in the preceding 1649 sections. In other words, an attribute constructed in fulfillment of 1650 a subscription will look the same as an attribute sent in direct 1651 response to an explicit request from a SWIMA-PV that had the same 1652 request parameters and which arrived immediately after the given 1653 change event. There are a few special rules that expand on this 1654 guideline: 1656 3.8.5.1. Subscriptions Reporting Inventories 1658 In the case that a SWIMA-PV subscribes to a SWIMA-PC requesting an 1659 inventory attribute whenever changes are detected (i.e., the EID in 1660 the establishing request is 0), then the SWIMA-PC MUST send the 1661 requested inventory whenever a relevant change is detected. (A 1662 "relevant change" is any change for untargeted requests, or a change 1663 to an indicated record in a targeted request.) Upon detection of a 1664 relevant change for an active subscription, the SWIMA-PC sends the 1665 appropriate inventory information as if it had just received the 1666 establishing request. Attributes sent in fulfillment of this 1667 subscription will probably have a large amount of redundancy, as the 1668 same records are likely to be present in each of these SWIMA 1669 Attributes. The role of an inventory subscription is not to report 1670 records just for the items that changed - that is the role of a 1671 subscription that reports events (see Section 3.8.5.2). A SWIMA-PC 1672 MUST NOT exclude a record from an attribute sent in fulfillment of an 1673 inventory subscription simply because that record was not involved in 1674 the triggering event (although a record might be excluded for other 1675 reasons, such as if the subscription is targeted - see 1676 Section 3.8.5.3). 1678 3.8.5.2. Subscriptions Reporting Events 1680 The way in which a SWIMA-PV indicates it wishes to establish a 1681 subscription requesting event records is by providing a non-zero EID 1682 in the SWIMA Request establishing the subscription (see 1683 Section 3.7.1). However, when the SWIMA-PC constructs an attribute 1684 in fulfillment of the subscription (other than the direct response to 1685 the establishing request), it MUST only include event records for the 1686 detected change(s) that precipitated this response attribute. In 1687 other words, it MUST NOT send a complete list of all changes starting 1688 with the establishing request's EID, up through the latest change, 1689 every time a new event is detected. In effect, the EID in the 1690 establishing request is treated as being updated every time an 1691 attribute is sent in fulfillment of this subscription, such that a 1692 single event is not reported twice in fulfillment of a single 1693 subscription. As such, every SWIMA-PC MUST track the EID of the last 1694 event that triggered an attribute for the given subscription. When 1695 the next event (or set of events) is detected, the SWIMA-PC MUST only 1696 report events with EIDs after the last reported event. In the case 1697 that the EID Epoch of the SWIMA-PC changes, the SWIMA-PC MUST reset 1698 this EID tracker to 0 (if the event log is completely purged) or to 1699 the new EID of the last reported retained event (if the event log is 1700 partially purged to create a "sliding window"). Doing this ensures 1701 that the SWIMA-PC continues to only send events that have not been 1702 previously reported. 1704 Note that while a subscription is active, the subscribing SWIMA-PV 1705 MAY make other requests for event records that overlap with events 1706 that are reported in fulfillment of a subscription. Such requests 1707 are unaffected by the presence of the subscription, nor is the 1708 subscription affected by such requests. In other words, a given 1709 request will get the same results back whether or not there was a 1710 subscription. Likewise, an attribute sent in fulfillment of a 1711 subscription will contain the same information whether or not other 1712 requests had been received from the SWIMA-PV. 1714 A SWIMA-PV needs to pay attention to the EID Epoch in these 1715 attributes, as changes in the Epoch might create discontinuities in 1716 the SWIMA-PV's understanding of the endpoint's Software Inventory 1717 Evidence Collection state, as discussed in Section 3.7.6. In 1718 particular, once the EID Epoch changes, a SWIMA-PV is unable to have 1719 confidence that it has a correct understanding of the state of an 1720 endpoint's Software Inventory Evidence Collection until after the 1721 SWIMA-PV collects a complete inventory. 1723 SWIMA-PCs MAY send partial lists of event records in fulfillment of a 1724 subscription. (See Section 3.7.5 for more on partial list of event 1725 records.) In the case that a SWIMA-PC sends a partial list of event 1726 records in fulfillment of a subscription, it MUST immediately send 1727 the next consecutive partial list, and continue doing so until it has 1728 sent the equivalent of the complete list of event records. In other 1729 words, if the SWIMA-PC sends a partial list it does not wait for 1730 another change event to send another SWIMA Response, but continues 1731 sending SWIMA Responses until it has sent all event records that 1732 would have been included in a complete fulfillment of the 1733 subscription. Note that the direct response to the establishing 1734 request is not considered to be sent in fulfillment of a 1735 subscription. However, in this case the SWIMA-PC MUST treat the 1736 presence of unreported events as a triggering event for pushing 1737 additional messages in fulfillment of the newly established 1738 subscription. As such, the net effect is that, if the direct 1739 response to the establishing request (i.e., the Subscription 1740 Fulfillment flag is unset) is partial, the SWIMA-PC will immediately 1741 follow this with additional attributes (with the Subscription 1742 Fulfillment flag set) until the complete set of events has been sent 1743 to the SWIMA-PV. 1745 3.8.5.3. Targeted Subscriptions 1747 Subscriptions MAY be targeted to only apply to records that match a 1748 given set of Software Identifiers. In the case where changes are 1749 detected that affect multiple records, some matching the establishing 1750 request's Software Identifiers and some not, the attribute sent in 1751 fulfillment of the subscription MUST only include inventory or events 1752 (as appropriate) for records that match the establishing request's 1753 Software Identifiers. The SWIMA-PC MUST NOT include non-matching 1754 records in the attribute, even if those non-matching records 1755 experienced change events that were co-temporal with change events on 1756 the matching records. 1758 In addition, a SWIMA-PC MUST send an attribute in fulfillment of a 1759 targeted subscription only when changes to the endpoint's Software 1760 Inventory Evidence Collection impact one or more records matching the 1761 subscription's establishing request's Software Identifiers. A SWIMA- 1762 PC MUST NOT send any attribute in fulfillment of a targeted 1763 subscription based on detected change to the endpoint's Software 1764 Inventory Evidence Collection that did not involve any of the records 1765 targeted by that subscription. 1767 3.8.5.4. No Subscription Consolidation 1769 A SWIMA-PV MAY establish multiple subscriptions to a given SWIMA-PC. 1770 If this is the case, it is possible that a single change event on the 1771 endpoint might require fulfillment by multiple subscriptions, and 1772 that the information included in attributes that fulfill each of 1773 these subscriptions might overlap. The SWIMA-PC MUST send separate 1774 attributes for each established subscription that requires a response 1775 due to the given event. Each of these attributes MUST contain all 1776 information required to fulfill that individual subscription, even if 1777 that information is also sent in other attributes sent in fulfillment 1778 of other subscriptions at the same time. In other words, SWIMA-PCs 1779 MUST NOT attempt to combine information when fulfilling multiple 1780 subscriptions simultaneously, even if this results in some redundancy 1781 in the attributes sent to the SWIMA-PV. 1783 3.8.5.5. Delayed Subscription Fulfillment 1785 A SWIMA-PC MAY delay the fulfillment of a subscription following a 1786 change event in the interest of waiting to see if additional change 1787 events are forthcoming and, if so, conveying the relevant records 1788 back to the SWIMA-PV in a single SWIMA Response attribute. This can 1789 help reduce network bandwidth consumption between the SWIMA-PC and 1790 the SWIMA-PV. For example, consider a situation where 10 changes 1791 occur a tenth of a second apart. If the SWIMA-PC does not delay in 1792 assembling and sending SWIMA Response attributes, the SWIMA-PV will 1793 receive 10 separate SWIMA Response attributes over a period of 1 1794 second. However, if the SWIMA-PC waits half a second after the 1795 initial event before assembling a SWIMA Response, the SWIMA-PV only 1796 receives two SWIMA Response attributes over the same period of time. 1798 Note that the ability to consolidate events for a single subscription 1799 over a given period of time does not contradict the rules in 1800 Section 3.8.5.4 prohibiting consolidation across multiple 1801 subscriptions. When delaying fulfillment of subscriptions, SWIMA-PCs 1802 are still required to fulfill each individual subscription 1803 separately. Moreover, in the case that change events within the 1804 delay window cancel each other out (e.g., a record is deleted and 1805 then re-added), the SWIMA-PC MUST still report each change event 1806 rather than just reporting the net effect of changes over the delay 1807 period. In other words, delayed fulfillment can decrease the number 1808 of attributes send by the SWIMA-PC, but it does not reduce the total 1809 number of change events reported. 1811 SWIMA-PCs are not required to support delayed fulfillment of 1812 subscriptions. However, in the case that the SWIMA-PC does support 1813 delayed subscription fulfillment, it MUST be possible to configure 1814 the SWIMA-PC to disable delayed fulfillment. In other words, parties 1815 deploying SWIMA-PCs need to be allowed to disable delayed 1816 subscription fulfillment in their SWIMA-PCs. The manner in which 1817 such configuration occurs is left to the discretion of implementers, 1818 although implementers MUST protect the configuration procedure from 1819 unauthorized tampering. In other words, there needs to be some 1820 assurance that unauthorized individuals are not able to introduce 1821 long delays in subscription fulfillment. 1823 3.9. Error Handling 1825 In the case where the SWIMA-PC detects an error in a SWIMA Request 1826 attribute that it receives it MUST respond with a PA-TNC Error 1827 attribute with an error code appropriate to the nature of the error. 1828 (See Section 4.2.8 of PA-TNC [RFC5792] for more details about PA-TNC 1829 Error attributes and error codes as well as Section 5.16 in this 1830 specification for error codes specific to SWIMA Attributes.) In the 1831 case that an error is detected in a SWIMA Request the SWIMA-PC MUST 1832 NOT take any action requested by this SWIMA Request, even if partial 1833 completion of the request is possible. In other words, a SWIMA 1834 Request that contains an error is completely ignored by the SWIMA-PC 1835 (beyond sending a PA-TNC Error attribute, and possibly logging the 1836 error locally) rather than being partially executed. 1838 In the case where the SWIMA-PC receives a valid SWIMA Request 1839 attribute but experiences an error during the process of responding 1840 to that attribute's instructions where that error prevents the SWIMA- 1841 PC from properly or completely fulfilling that request, the SWIMA-PC 1842 MUST send a PA-TNC Error attribute with an error code appropriate to 1843 the nature of the error. In the case where a PA-TNC Error attribute 1844 is sent, the SWIMA-PC MUST NOT take any of the actions requested by 1845 the SWIMA Request attribute which led to the detected error. This is 1846 the case even if some actions could have been completed successfully, 1847 and might even require the SWIMA-PC to reverse some successful 1848 actions already taken before the error condition was detected. In 1849 other words, either all aspects of a SWIMA Request complete fully and 1850 successfully (in which case the SWIMA-PC sends a SWIMA Response 1851 attribute), or no aspects of the SWIMA Request occur (in which case 1852 the SWIMA-PC sends a PA-TNC Error attribute). In the case that a 1853 SWIMA-PC sends a PA-TNC Error attribute in response to a SWIMA 1854 Request then the SWIMA-PC MUST NOT also send any SWIMA Response 1855 attribute in response to the same SWIMA Request. For this reason, 1856 the sending of a SWIMA Response attribute MUST be the last action 1857 taken by a SWIMA-PC in response to a SWIMA Request to avoid the 1858 possibility of a processing error occurring after that SWIMA Response 1859 attribute is sent. 1861 In the case that the SWIMA-PC detects an error that prevents it from 1862 properly or completely fulfilling its obligations under an active 1863 subscription, the SWIMA-PC MUST send a PA-TNC Error attribute of type 1864 SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR to the SWIMA-PV that established 1865 this subscription. This type of PA-TNC Error attribute identifies 1866 the specific subscription that cannot be adequately honored due to 1867 the error condition as well as an error "sub-type". The error sub- 1868 type is used to indicate the type of error condition the SWIMA-PC 1869 experienced that prevented it from honoring the given subscription. 1870 In the case that the error condition cannot be identified or does not 1871 align with any of the defined error codes, the SWIMA_ERROR error code 1872 SHOULD be used in the sub-type. In the case that a 1873 SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR is sent, the associated 1874 subscription MUST be treated as cancelled by both the SWIMA-PC and 1875 SWIMA-PV. 1877 The SWIMA-PV MUST NOT send any PA-TNC Error attributes to SWIMA-PCs. 1878 In the case that a SWIMA-PV detects an error condition, it SHOULD log 1879 this error but does not inform any SWIMA-PC's of this event. Errors 1880 might include, but are not limited to, detection of malformed SWIMA 1881 Response attributes sent from a given SWIMA-PC, as well as detection 1882 of error conditions when the SWIMA-PV processes SWIMA Responses. 1884 Both SWIMA-PCs and SWIMA-PVs SHOULD log errors so that administrators 1885 can trace the causes of errors. Log entries SHOULD include the type 1886 of the error, the time it was detected, and additional descriptive 1887 information to aid in understanding the nature and cause of the 1888 error. Logs are an important debugging tool and implementers are 1889 strongly advised to include comprehensive logging capabilities in 1890 their products. 1892 4. Protocol 1894 The software inventory protocol supports two different types of 1895 message exchanges which are described the following subsections, 1896 along with implementation requirements for supporting these 1897 exchanges. 1899 4.1. Direct Response to a SWIMA Request 1901 The first type of exchange is used to provide the SWIMA-PV with a 1902 software inventory or event collection from the queried endpoint. 1904 +-------------+ +--------------+ 1905 | SWIMA-PC | | SWIMA-PV | Time 1906 +-------------+ +--------------+ | 1907 | | | 1908 |<-----------SWIMA Request------------| | 1909 | | | 1910 | SWIMA Response* | | 1911 |-----------------or----------------->| | 1912 | PA-TNC Error | | 1913 | | V 1915 *SWIMA Response is one of the following: Software Identifier 1916 Inventory, Software Identifier Events, Software Inventory, 1917 or Software Events. 1919 Figure 4: SWIMA Attribute Exchange (Direct Response to SWIMA Request) 1921 In this exchange, the SWIMA-PV indicates to the SWIMA-PC, via a SWIMA 1922 Request, the nature of the information it wishes to receive 1923 (inventory vs. events, full or targeted) and how it wishes the 1924 returned inventory to be expressed (with or without software 1925 inventory evidence records). The SWIMA-PC responds with the 1926 requested information using the appropriate attribute type. A single 1927 SWIMA Request MUST only lead to a single SWIMA Response or PA-TNC 1928 Error that is in direct response to that request. 1930 4.2. Subscription-Based Response 1932 The second type of exchange allows change event-based reporting based 1933 on a subscription. If there is an active subscription on the 1934 endpoint, the SWIMA-PC sends a SWIMA Response to the SWIMA-PV 1935 following a change event on the endpoint in fulfillment of that 1936 subscription. Such an exchange is shown in Figure 5. 1938 +-------------+ +--------------+ 1939 | SWIMA-PC | | SWIMA-PV | Time 1940 +-------------+ +--------------+ | 1941 | | | 1942 | | | 1943 |------SWIMA Response(s)*------>| | 1944 | | | 1946 *SWIMA Response is one of the following: Software Identifier 1947 Inventory, Software Identifier Events, Software Inventory, 1948 or Software Events. 1950 Figure 5: SWIMA Attribute Exchange (In Fulfillment of an Active 1951 Subscription) 1953 Note that, unlike direct responses to a SWIMA Request, a single 1954 change event can precipitate multiple SWIMA Responses for a single 1955 subscription, but only if all but the last of those SWIMA Responses 1956 convey partial lists of event records. When providing multiple SWIMA 1957 Responses in this way, the initial responses contain partial lists of 1958 event records and the last of those SWIMA Responses conveys the 1959 remainder of the relevant event records, completing the delivery of 1960 all relevant events in response to the change event. A single Change 1961 Event MUST NOT otherwise be followed by multiple SWIMA Response or 1962 PA-TNC Error attributes in any combination. 1964 4.3. Required Exchanges 1966 All SWIMA-PVs and SWIMA-PCs MUST support both types of exchanges. In 1967 particular, SWIMA-PCs MUST be capable of pushing a SWIMA Response to 1968 a SWIMA-PV immediately upon detection of a change to the endpoint's 1969 Software Inventory Evidence Collection in fulfillment of established 1970 SWIMA-PV subscriptions, as described in Section 3.8. 1972 5. Software Inventory Messages and Attributes 1974 This section describes the format and semantics of the SWIMA 1975 protocol. This protocol uses the PA-TNC message header format 1976 [RFC5792]. 1978 5.1. PA Subtype (AKA PA-TNC Component Type) 1980 The NEA PB-TNC interface provides a general message-batching protocol 1981 capable of carrying one or more PA-TNC messages between the Posture 1982 Broker Client and Posture Broker Server. When PB-TNC is carrying a 1983 PA-TNC message, the PB-TNC message headers contain a 32 bit 1984 identifier called the PA Subtype. The PA Subtype field indicates the 1985 type of component associated with all of the PA-TNC attributes 1986 carried by the PB-TNC message. The core set of PA Subtypes is 1987 defined in the PA-TNC specification. This specification defines a 1988 new "SWIMA Attributes" PA Subtype, which is registered in 1989 Section 10.1 of this document, which is used as a namespace for the 1990 collection of SWIMA Attributes defined in this document. 1992 For more information on PB-TNC and PA-TNC messages and message 1993 headers, see the PB-TNC [RFC5793] and PA-TNC [RFC5792] 1994 specifications, respectively. 1996 5.2. SWIMA Attribute Overview 1998 Each PA-TNC attribute described in this specification is intended to 1999 be sent between the SWIMA-PC and SWIMA-PV, so will be carried in a 2000 PB-TNC message indicating a PA Subtype of "SWIMA Attributes". PB-TNC 2001 messages MUST always include the SWIMA Attributes Subtype defined in 2002 Section 5.1 when carrying SWIMA Attributes over PA-TNC. The 2003 attributes defined in this specification appear below along with a 2004 short summary of their purposes. 2006 PA-TNC attribute types are identified in the PA-TNC Attribute Header 2007 via the Attribute Type Vendor ID and Attribute Type fields. Table 1 2008 identifies the appropriate values for these fields for each attribute 2009 type used within the SWIMA protocol. All attributes have a PEN value 2010 of 0x000000. For the Integer value field, both the hexadecimal and 2011 decimal values are provided. Each attribute is described in greater 2012 detail in subsequent sections identified in the attribute 2013 description. 2015 +--------------+------------+---------------------------------------+ 2016 | Attribute | Integer | Description | 2017 | Name | | | 2018 +--------------+------------+---------------------------------------+ 2019 | SWIMA | 0x0000000D | Request sent from a SWIMA-PV to a | 2020 | Request | (13) | SWIMA-PC for the SWIMA-PC to provide | 2021 | | | a software inventory or event list. | 2022 | | | It might also establish a | 2023 | | | subscription. (Section 5.7) | 2024 | | | | 2025 | Software | 0x0000000E | An inventory sent without software | 2026 | Identifier | (14) | inventory evidence records sent from | 2027 | Inventory | | a SWIMA-PC. (Section 5.8) | 2028 | | | | 2029 | Software | 0x0000000F | A collection of events impacting the | 2030 | Identifier | (15) | endpoint's Software Inventory | 2031 | Events | | Evidence Collection, where events do | 2032 | | | not include software inventory | 2033 | | | evidence records. (Section 5.9) | 2034 | | | | 2035 | Software | 0x00000010 | An inventory including software | 2036 | Inventory | (16) | inventory evidence records sent from | 2037 | | | a SWIMA-PC. (Section 5.10) | 2038 | | | | 2039 | Software | 0x00000011 | A collection of events impacting the | 2040 | Events | (17) | endpoint's Software Inventory | 2041 | | | Evidence Collection, where events | 2042 | | | include software inventory evidence | 2043 | | | records. (Section 5.11) | 2044 | | | | 2045 | Subscription | 0x00000012 | A request for a list of a SWIMA-PV's | 2046 | Status | (18) | active subscription on a SWIMA-PC. | 2047 | Request | | (Section 5.12) | 2048 | | | | 2049 | Subscription | 0x00000013 | A list of a SWIMA-PV's active | 2050 | Status | (19) | subscriptions on a SWIMA-PC. (Section | 2051 | Response | | 5.13) | 2052 | | | | 2053 | Source | 0x00000014 | A request for information about a | 2054 | Metadata | (20) | SWIMA-PC's data sources. (Section | 2055 | Request | | 5.14) | 2056 | | | | 2057 | Subscription | 0x00000015 | Descriptive metadata about a SWIMA- | 2058 | Metadata | (21) | PC's data sources. (Section 5.15) | 2059 | Response | | | 2060 | | | | 2061 | PA-TNC Error | 0x00000008 | An error attribute as defined in the | 2062 | | (8) | PA-TNC specification [RFC5792]. | 2063 +--------------+------------+---------------------------------------+ 2065 Table 1: SWIMA Attribute Enumeration 2067 Because one of the Software Identifier Inventory, Software Identifier 2068 Events, Software Inventory, or Software Events attributes are 2069 expected to be sent to a SWIMA-PV in direct response to a SWIMA 2070 Request attribute or in fulfillment of an active subscription, those 2071 four attribute types are referred to collectively in this document as 2072 "SWIMA Response attributes". 2074 All SWIMA-PVs MUST be capable of sending SWIMA Request attributes and 2075 be capable of receiving and processing all SWIMA Response attributes 2076 as well as PA-TNC Error attributes. All SWIMA-PCs MUST be capable of 2077 receiving and processing SWIMA Request attributes and be capable of 2078 sending all types of SWIMA Response attributes as well as PA-TNC 2079 Error attributes. In other words, both SWIMA-PVs and SWIMA-PCs are 2080 required to support their role in exchanges using any of the 2081 attribute types defined in this section. SWIMA-PVs MUST ignore any 2082 SWIMA Request attributes that they receive. SWIMA-PCs MUST ignore 2083 any SWIMA Response attributes or PA-TNC Error attributes that they 2084 receive. 2086 5.3. Message Diagram Syntax 2088 This specification defines the syntax of new PA-TNC messages and 2089 attributes using diagrams. Each diagram depicts the format and size 2090 of each field in bits. Implementations MUST send the bits in each 2091 diagram as they are shown from left to right for each 32-bit quantity 2092 traversing the diagram from top to bottom. Fields representing 2093 numeric values MUST be sent in network (big endian) byte order. 2095 Descriptions of bit fields (e.g., flags) values refer to the position 2096 of the bit within the field. These bit positions are numbered from 2097 the most significant bit through the least significant bit. As such, 2098 an octet with only bit 0 set would have a value of 0x80 (1000 0000), 2099 an octet with only bit 1 set would have a value of 0x40 (0100 0000), 2100 and an octet with only bit 7 set would have a value of 0x01 (0000 2101 0001). 2103 5.4. SWIMA Attribute Enumeration 2105 5.5. Normalization of Text Encoding 2107 In order to ensure consistency of transmitted attributes some fields 2108 require normalization of their format. When this is necessary, this 2109 is indicated in the field's description. In such cases, the field 2110 contents MUST be normalized to Network Unicode format as defined in 2111 RFC 5198 [RFC5198]. Network Unicode format defines a refinement of 2112 UTF-8 [RFC3629] that ensures a normalized expression of characters. 2113 SWIMA-PCs and SWIMA-PVs MUST NOT perform conversion and normalization 2114 on any field values except those specifically identified as requiring 2115 normalization in the following sections. Note, however, that some 2116 data models require additional normalization before source 2117 information is added to an Endpoint's Inventory Evidence Collection 2118 as a record. The references from the Software Data Model IANA table 2119 (see Section 10.4) will note where this is necessary. 2121 5.6. Request IDs 2123 All SWIMA Request attributes MUST include a Request ID value. The 2124 Request ID field provides a value that identifies a given request 2125 relative to other requests between a SWIMA-PV and the receiving 2126 SWIMA-PC. Specifically, the SWIMA-PV assigns each SWIMA Request 2127 attribute a Request ID value that is intended to be unique within the 2128 lifetime of a given network connection ID as assigned by the SWIMA- 2129 PV's Posture Broker Server. 2131 In the case that a SWIMA Request requests the establishment of a 2132 subscription and the receiving SWIMA-PC agrees to that subscription, 2133 the Request ID of that SWIMA Request (i.e., the establishing request 2134 of the subscription) becomes that subscription's Subscription ID. 2135 All attributes sent in fulfillment of this subscription include a 2136 flag indicating that the attribute fulfills a subscription and the 2137 subscription's Subscription ID. A SWIMA-PV MUST NOT reuse a Request 2138 ID value in communicating to a given SWIMA-PC while that Request ID 2139 is also serving as a Subscription ID for an active subscription with 2140 that SWIMA-PC. In the case where a SWIMA-PC receives a SWIMA Request 2141 from a given SWIMA-PV where that Request ID is also the Subscription 2142 ID of an active subscription with that SWIMA-PV, the SWIMA-PC MUST 2143 respond with a PA-TNC Error attribute with an error code of 2144 SWIMA_SUBSCRIPTION_ID_REUSE_ERROR. Note that this error does not 2145 cancel the indicated subscription. 2147 Subscription Status Requests and Subscription Status Responses do not 2148 include Request IDs. 2150 In the case where all possible Request ID values have been exhausted 2151 within the lifetime of a single network connection ID, the sender MAY 2152 reuse previously used Request IDs within the same network connection 2153 if the ID is not being used as a Subscription ID. In such a case of 2154 Request ID reuse, Request IDs SHOULD be reused in the order of their 2155 original use. In other words, a SWIMA-PC SHOULD NOT use a given 2156 Request ID value more than once within a persistent connection 2157 between a given Posture Broker Client-Posture Broker Server pair. In 2158 the case where reuse is necessary due to exhaustion of possible ID 2159 values, the SWIMA-PC SHOULD structure the reuse to maximize the time 2160 between original and subsequent use. The Request ID value is 2161 included in a SWIMA Response attribute directly responding to this 2162 SWIMA Request to indicate which SWIMA Request was received and caused 2163 the response. Request IDs can be randomly generated or sequential, 2164 as long as values are not repeated per the rules in this paragraph. 2165 SWIMA-PCs are not required to check for duplicate Request IDs. 2167 5.7. SWIMA Request 2169 A SWIMA-PV sends this attribute to a SWIMA-PC to request that the 2170 SWIMA-PC send software inventory information to the SWIMA-PV. A 2171 SWIMA-PC MUST NOT send this attribute. 2173 1 2 3 2174 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2176 | Flags | Software Identifier Count | 2177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2178 | Request ID | 2179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2180 | Earliest EID | 2181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2182 | | 2183 | SUB-BLOCK (Repeated "Software Identifier Count" times) | 2184 | | 2185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2187 Figure 6: SWIMA Request Attribute 2189 1 2 3 2190 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2192 | Software Identifier Length | Software Identifier (var len) | 2193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2195 Figure 7: SWIMA Request Attribute SUB-BLOCK 2197 +---------------+---------------------------------------------------+ 2198 | Field | Description | 2199 +---------------+---------------------------------------------------+ 2200 | Flags: Bit 0 | If set (1), the SWIMA-PC MUST delete all | 2201 | - Clear | subscriptions established by the requesting | 2202 | Subscriptions | SWIMA-PV (barring any errors). | 2203 | | | 2204 | Flags: Bit 1 | If set (1), in addition to responding to the | 2205 | - Subscribe | request as described, the SWIMA-PC MUST establish | 2206 | | a subscription with parameters matching those in | 2207 | | the request attribute (barring any errors). | 2208 | | | 2209 | Flags: Bit 2 | If unset (0), the SWIMA-PC's response MUST | 2210 | - Result Type | include software inventory evidence records and | 2211 | | thus the response MUST be a Software Inventory, a | 2212 | | Software Events, or a PA-TNC Error attribute. If | 2213 | | set (1), the response MUST NOT include software | 2214 | | inventory evidence records and thus the response | 2215 | | MUST be a Software Identifier Inventory, a | 2216 | | Software Identifier Events, or a PA-TNC Error | 2217 | | attribute. | 2218 | | | 2219 | Flags: Bit | Reserved for future use. This field MUST be set | 2220 | 3-7 - | to zero on transmission and ignored upon | 2221 | Reserved | reception. | 2222 | | | 2223 | Software | A 3-byte unsigned integer indicating the number | 2224 | Identifier | of Software Identifiers that follow. If this | 2225 | Count | value is non-zero, this is a targeted request, as | 2226 | | described in Section 3.5. The Software | 2227 | | Identifier Length and Software Identifier fields | 2228 | | are repeated, in order, the number of times | 2229 | | indicated in this field. In the case where | 2230 | | Software Identifiers are present, the SWIMA-PC | 2231 | | MUST only report software that corresponds to the | 2232 | | identifiers the SWIMA-PV provided in this | 2233 | | attribute (or with a PA-TNC Error attribute). | 2234 | | This field value MAY be 0, in which case there | 2235 | | are no instances of the Software Identifier | 2236 | | Length and Software Identifier fields. In this | 2237 | | case, the SWIMA-PV is indicating an interest in | 2238 | | all software inventory evidence records on the | 2239 | | endpoint (i.e., this is not a targeted request). | 2240 | | | 2241 | Request ID | A value that uniquely identifies this SWIMA | 2242 | | Request from a particular SWIMA-PV. | 2243 | | | 2244 | Earliest EID | In the case where the SWIMA-PV is requesting | 2245 | | software events, this field contains the EID | 2246 | | value of the earliest event the SWIMA-PV wishes | 2247 | | to have reported. (Note - the report will be | 2248 | | inclusive of the event with this EID value.) In | 2249 | | the case where the SWIMA-PV is requesting an | 2250 | | inventory, then this field MUST be 0. | 2251 | | (0x00000000) In the case where this field is non- | 2252 | | zero, the SWIMA-PV is requesting events and the | 2253 | | SWIMA-PC MUST respond using a Software Events, | 2254 | | Software Identifier Events, or a PA-TNC Error | 2255 | | attribute. In the case where this field is zero, | 2256 | | the SWIMA-PV is requesting an inventory and the | 2257 | | SWIMA-PC MUST respond using a Software Inventory, | 2258 | | a Software Identifier Inventory, or a PA-TNC | 2259 | | Error attribute. | 2260 | | | 2261 | Software | A 2-byte unsigned integer indicating the length | 2262 | Identifier | in bytes of the Software Identifier field. | 2263 | Length | | 2264 | | | 2265 | Software | A string containing the Software Identifier value | 2266 | Identifier | from a software inventory evidence record. This | 2267 | | field value MUST be normalized to Network Unicode | 2268 | | format, as described in Section 5.5. This string | 2269 | | MUST NOT be NULL terminated. | 2270 +---------------+---------------------------------------------------+ 2272 Table 2: SWIMA Request Attribute Fields 2274 The SWIMA-PV sends the SWIMA Request attribute to a SWIMA-PC to 2275 request the indicated information. Note that between the Result Type 2276 flag and the Earliest EID field, the SWIMA-PC is constrained to a 2277 single possible SWIMA Response attribute type (or a PA-TNC Error 2278 attribute) in its response to the request. 2280 The Subscribe and Clear Subscription flags are used to manage 2281 subscriptions for the requesting SWIMA-PV on the receiving SWIMA-PC. 2282 Specifically, an attribute with the Subscribe flag set seeks to 2283 establish a new subscription by the requesting SWIMA-PV to the given 2284 SWIMA-PC, while an attribute with the Clear Subscription flag seeks 2285 to delete all existing subscriptions by the requesting SWIMA-PV on 2286 the given SWIMA-PC. Note that, in the latter case, only the 2287 subscriptions associated with the Connection ID and the Posture 2288 Validator ID of the requester are deleted as described in 2289 Section 3.8.3. A newly established subscription has the parameters 2290 outlined in the Request attribute. Specifically, the Result Type 2291 flag indicates the type of result to send in fulfillment of the 2292 subscription, the value of the Earliest EID field indicates whether 2293 the fulfillment attributes list inventories or events, and the fields 2294 describing Software Identifiers (if present) indicate if and how a 2295 subscription is targeted. In the case that the SWIMA-PC is unable or 2296 unwilling to comply with the SWIMA-PV's request to establish or clear 2297 subscriptions, the SWIMA-PC MUST respond with a PA-TNC Error 2298 attribute with the SWIMA_SUBSCRIPTION_DENIED_ERROR error code. If 2299 the SWIMA-PV requests that subscriptions be cleared but has no 2300 existing subscriptions, this is not an error. 2302 An attribute requesting the establishment of a subscription is 2303 effectively doing double-duty, as it is a request for an immediate 2304 response from the SWIMA-PC in addition to setting up the 2305 subscription. Assuming the SWIMA-PC is willing to comply with the 2306 subscription it MUST send an appropriate response attribute to a 2307 request with the Subscribe flag set containing all requested 2308 information. The same is true of the Clear Subscription flag - 2309 assuming there is no error the SWIMA-PC MUST generate a response 2310 attribute without regard to the presence of this flag in addition to 2311 clearing its subscription list. 2313 Both the Subscribe and Clear Subscription flags MAY be set in a 2314 single SWIMA Request attribute. In the case where this request is 2315 successful, the end result MUST be equivalent to the SWIMA-PC 2316 clearing its subscription list for the given SWIMA-PV first and then 2317 creating a new subscription in accordance with the request 2318 parameters. In other words, do not first create the new subscription 2319 and then clear all the subscriptions including the one that was just 2320 created. In the case that the requested actions are successfully 2321 completed, the SWIMA-PC MUST respond with a SWIMA Response attribute. 2322 The specific type of SWIMA Response attribute depends on the Result 2323 Type and Earliest EID fields, as described above. In the case where 2324 there is a failure that prevents some part this request from 2325 completing, the SWIMA-PC MUST NOT add a new subscription, MUST NOT 2326 clear the old subscriptions, and the SWIMA-PC MUST respond with a PA- 2327 TNC Error attribute. In other words, the SWIMA-PC MUST NOT partially 2328 succeed at implementing such a request; either all actions succeed, 2329 or none succeed. 2331 The Earliest EID field is used to indicate if the SWIMA-PV is 2332 requesting an inventory or event list from the SWIMA-PC. A value of 2333 0 (0x00000000) represents a request for inventory information. 2334 Otherwise, the SWIMA-PV is requesting event information. For 2335 Earliest EID values other than 0, the SWIMA-PC's response MUST 2336 respond with event records, as described in Section 3.7. Note that 2337 the request does not identify a particular EID Epoch, since responses 2338 can only include events in the SWIMA-PC's current EID Epoch. 2340 The Software Identifier Count indicates the number of Software 2341 Identifiers in the attribute. This number might be any value between 2342 0 and 16,777,216, inclusive. A single Software Identifier is 2343 represented by the following fields: Software Identifier Length and 2344 Software Identifier. These fields are repeated a number of times 2345 equal to the Software Identifier Count, which may be 0. The Software 2346 Identifier Length field indicates the number of bytes allocated to 2347 the Software Identifier field. The Software Identifier field 2348 contains a Software Identifier as describe in Section 3.4.1. The 2349 presence of one or more Software Identifiers is used by the SWIMA-PV 2350 to indicate a targeted request, which seeks only inventories of or 2351 events affecting software corresponding to the given identifiers. 2352 The SWIMA-PC MUST only report software that matched the Software 2353 Identifiers provided in the SWIMA-PVs SWIMA Request attribute. 2355 5.8. Software Identifier Inventory 2357 A SWIMA-PC sends this attribute to a SWIMA-PV to convey the inventory 2358 of the endpoint's Software Inventory Evidence Collection without the 2359 inclusion of software inventory evidence records. This list might 2360 represent a complete inventory or a targeted list of records, 2361 depending on the parameters in the SWIMA-PV's request. A SWIMA-PV 2362 MUST NOT send this attribute. The SWIMA-PC either sends this 2363 attribute in fulfillment of an existing subscription where the 2364 establishing request has a Result Type of 1 and the Earliest EID is 2365 zero, or in direct response to a SWIMA Request attribute where the 2366 Result Type is 1 and the Earliest EID is zero. 2368 1 2 3 2369 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2370 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2371 | Flags | Software Identifier Count | 2372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2373 | Request ID Copy / Subscription ID | 2374 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2375 | EID Epoch | 2376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2377 | Last EID | 2378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2379 | | 2380 | SUB-BLOCK (Repeated "Software Identifier Count" times) | 2381 | | 2382 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2384 Figure 8: Software Identifier Inventory Attribute 2386 1 2 3 2387 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2389 | Record Identifier | 2390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2391 | Data Model Type PEN |Data Model Type| 2392 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2393 | Source Id Num | Software Identifier Length |Software Id (v)| 2394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2395 | Software Locator Length |Software Locator (variable len)| 2396 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2398 Figure 9: Software Identifier Inventory Attribute SUB-BLOCK 2400 +----------------+--------------------------------------------------+ 2401 | Field | Description | 2402 +----------------+--------------------------------------------------+ 2403 | Flags: Bit 0 - | In the case that this attribute is sent in | 2404 | Subscription | fulfillment of a subscription this bit MUST be | 2405 | Fulfillment | set (1). In the case that this attribute is a | 2406 | | direct response to a SWIMA Request, this bit | 2407 | | MUST be unset (0). | 2408 | | | 2409 | Flags: Bit 1-7 | Reserved for future use. This field MUST be set | 2410 | - Reserved | to zero on transmission and ignored upon | 2411 | | reception. | 2412 | | | 2413 | Software | The number of Software Identifiers that follow. | 2414 | Identifier | This field is an unsigned integer. The Record | 2415 | Count | Identifier, Data Model Type PEN, Data Model | 2416 | | Type, Source Identification Number, Software | 2417 | | Identifier Length, Software Identifier, Software | 2418 | | Locator Length, and Software Locator fields are | 2419 | | repeated, in order, the number of times | 2420 | | indicated in this field. This field value MAY be | 2421 | | 0, in which case there are no instances of these | 2422 | | fields. | 2423 | | | 2424 | Request ID | In the case where this attribute is in direct | 2425 | Copy / | response to a SWIMA Request attribute from a | 2426 | Subscription | SWIMA-PV, this field MUST contain an exact copy | 2427 | ID | of the Request ID field from that SWIMA Request. | 2428 | | In the case where this attribute is sent in | 2429 | | fulfillment of an active subscription, this | 2430 | | field MUST contain the Subscription ID of the | 2431 | | subscription being fulfilled by this attribute. | 2432 | | | 2433 | EID Epoch | The EID Epoch of the Last EID value. This field | 2434 | | is an unsigned 4-byte unsigned integer. | 2435 | | | 2436 | Last EID | The EID of the last event recorded by the SWIMA- | 2437 | | PC, or 0 if the SWIMA-PC has no recorded events. | 2438 | | This field is an unsigned 4-byte unsigned | 2439 | | integer. | 2440 | | | 2441 | Record | A 4-byte unsigned integer containing the Record | 2442 | Identifier | Identifier value from a software inventory | 2443 | | evidence record. | 2444 | | | 2445 | Data Model | A 3-byte unsigned integer containing the Private | 2446 | Type PEN | Enterprise Number (PEN) of the organization that | 2447 | | assigned the meaning of the Data Model Type | 2448 | | value. | 2449 | | | 2450 | Data Model | A 1-byte unsigned integer containing an | 2451 | Type | identifier number that identifies the data model | 2452 | | of the reported record. | 2453 | | | 2454 | Source | The Source Identification Number associated with | 2455 | Identification | the source from which this software installation | 2456 | Number | inventory instance was reported. | 2457 | | | 2458 | Software | A 2-byte unsigned integer indicating the length | 2459 | Identifier | in bytes of the SW ID field. | 2460 | Length | | 2461 | | | 2462 | Software | A string containing the Software Identifier | 2463 | Identifier | value from a software inventory evidence record. | 2464 | | This field value MUST be normalized to Network | 2465 | | Unicode format as described in Section 5.5. This | 2466 | | string MUST NOT be NULL terminated. | 2467 | | | 2468 | Software | A 2-byte unsigned integer indicating the length | 2469 | Locator Length | in bytes of the Software Locator field. | 2470 | | | 2471 | Software | A string containing the Software Locator value. | 2472 | Locator | This field value MUST first be normalized to | 2473 | | Network Unicode format, as described in Section | 2474 | | 5.5, and then encoded as a URI [RFC3986]. This | 2475 | | string MUST NOT be NULL terminated. | 2476 +----------------+--------------------------------------------------+ 2478 Table 3: Software Identifier Inventory Attribute Fields 2480 In the case that this attribute is sent in fulfillment of a 2481 subscription, the Subscription Fulfillment bit MUST be set (1). In 2482 the case that this attribute is sent in direct response to a SWIMA 2483 Request, the Subscription Fulfillment bit MUST be unset (0). Note 2484 that the SWIMA Response attribute sent in direct response to a SWIMA 2485 Request that establishes a subscription (i.e., a subscription's 2486 establishing request) MUST be treated as a direct response to that 2487 SWIMA Request (and thus the Subscription Fulfillment bit is unset). 2488 SWIMA Response attributes are only treated as being in fulfillment of 2489 a subscription (i.e., Subscription Fulfillment bit set) if they are 2490 sent following a change event, as shown in Figure 3. 2492 The Software Identifier Count field indicates the number of Software 2493 Identifiers present in this inventory. Each Software Identifier is 2494 represented by the following set of fields: Record Identifier, Data 2495 Model Type, Software Identifier Length, Software Identifier, Software 2496 Locator Length, and Software Locator. These fields will appear once 2497 for each reported record. 2499 When responding directly to a SWIMA Request attribute, the Request ID 2500 Copy / Subscription ID field MUST contain an exact copy of the 2501 Request ID field from that SWIMA Request. When this attribute is 2502 sent in fulfillment of an existing subscription on this Posture 2503 Collector, then this field MUST contain the Subscription ID of the 2504 fulfilled subscription. 2506 The EID Epoch field indicates the EID Epoch of the Last EID value. 2507 The Last EID field MUST contain the EID of the last recorded change 2508 event (see Section 3.7 for more about EIDs and recorded events) at 2509 the time this inventory was collected. In the case where there are 2510 no recorded change events at the time that this inventory was 2511 collected, the Last EID field MUST contain 0. These fields can be 2512 interpreted to indicate that the provided inventory reflects the 2513 state of the endpoint after all changes up to and including this last 2514 event have been accounted for. 2516 The Data Model Type PEN and Data Model Type fields are used to 2517 identify the data model associated with the given software record. 2518 These fields are discussed more in Section 3.4.2. 2520 The Source Identification Number field is used to identify the source 2521 that provided the given record, as described in Section 3.1. 2523 5.9. Software Identifier Events 2525 A SWIMA-PC sends this attribute to a SWIMA-PV to convey events where 2526 the affected records are reported without software inventory evidence 2527 records. A SWIMA-PV MUST NOT send this attribute. The SWIMA-PC 2528 either sends this attribute in fulfillment of an existing 2529 subscription where the establishing request has a Result Type is 1 2530 and the Earliest EID is non-zero, or in direct response to a SWIMA 2531 Request attribute where the Result Type is 1 and the Earliest EID is 2532 non-zero. 2534 1 2 3 2535 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2536 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2537 | Flags | Event Count | 2538 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2539 | Request ID Copy / Subscription ID | 2540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2541 | EID Epoch | 2542 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2543 | Last EID | 2544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2545 | Last Consulted EID | 2546 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2547 | | 2548 | SUB-BLOCK (Repeated "Event Count" times) | 2549 | | 2550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2552 Figure 10: Software Identifier Events Attribute 2553 1 2 3 2554 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2556 | EID | 2557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2558 | | 2559 +- -+ 2560 | | 2561 +- -+ 2562 | Timestamp | 2563 +- -+ 2564 | | 2565 +- -+ 2566 | | 2567 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2568 | Record Identifier | 2569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2570 | Data Model Type PEN |Data Model Type| 2571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2572 | Source Id Num | Action | Software Identifier Length | 2573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2574 | Software Identifier (variable length) | 2575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2576 | Software Locator Length |Software Locator (variable len)| 2577 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2579 Figure 11: Software Identifier Events Attribute SUB-BLOCK 2581 +----------------+--------------------------------------------------+ 2582 | Field | Description | 2583 +----------------+--------------------------------------------------+ 2584 | Flags: Bit 0 - | In the case that this attribute is sent in | 2585 | Subscription | fulfillment of a subscription this bit MUST be | 2586 | Fulfillment | set (1). In the case that this attribute is a | 2587 | | direct response to a SWIMA Request, this bit | 2588 | | MUST be unset (0). | 2589 | | | 2590 | Flags: Bit 1-7 | Reserved for future use. This field MUST be set | 2591 | - Reserved | to zero on transmission and ignored upon | 2592 | | reception. | 2593 | | | 2594 | Event Count | The number of events that are reported in this | 2595 | | attribute. This field is a 3-byte unsigned | 2596 | | integer. The EID, Timestamp, Record Identifier, | 2597 | | Data Model Type PEN, Data Model Type, Source | 2598 | | Identification Number, Action, Software | 2599 | | Identifier Length, Software Identifier, Software | 2600 | | Locator Length, and Software Locator fields are | 2601 | | repeated, in order, the number of times | 2602 | | indicated in this field. This field value MAY be | 2603 | | 0, in which case there are no instances of these | 2604 | | fields. | 2605 | | | 2606 | Request ID | In the case where this attribute is in direct | 2607 | Copy / | response to a SWIMA Request attribute from a | 2608 | Subscription | SWIMA-PV, this field MUST contain an exact copy | 2609 | ID | of the Request ID field from that SWIMA Request. | 2610 | | In the case where this attribute is sent in | 2611 | | fulfillment of an active subscription, this | 2612 | | field MUST contain the Subscription ID of the | 2613 | | subscription being fulfilled by this attribute. | 2614 | | | 2615 | EID Epoch | The EID Epoch of the Last EID value. This field | 2616 | | is an unsigned 4-byte unsigned integer. | 2617 | | | 2618 | Last EID | The EID of the last event recorded by the SWIMA- | 2619 | | PC, or 0 if the SWIMA-PC has no recorded events. | 2620 | | This field contains the EID of the SWIMA-PC's | 2621 | | last recorded change event (which might or might | 2622 | | not be included as an event record in this | 2623 | | attribute). | 2624 | | | 2625 | Last Consulted | The EID of the last event record that was | 2626 | EID | consulted when generating the event record list | 2627 | | included in this attribute. This is different | 2628 | | from the Last EID field value if and only if | 2629 | | this attribute is conveying a partial list of | 2630 | | event records. See Section 3.7.5 for more on | 2631 | | partial list of event records. | 2632 | | | 2633 | EID | The EID of the event in this event record. | 2634 | | | 2635 | Timestamp | The timestamp associated with the event in this | 2636 | | event record. This timestamp is the SWIMA-PC's | 2637 | | best understanding of when the given event | 2638 | | occurred. Note that this timestamp might be an | 2639 | | estimate. The Timestamp date and time MUST be | 2640 | | represented as an RFC 3339 [RFC3339] compliant | 2641 | | ASCII string in Coordinated Universal Time (UTC) | 2642 | | time with the additional restrictions that the | 2643 | | 'T' delimiter and the 'Z' suffix MUST be | 2644 | | capitalized and fractional seconds (time- | 2645 | | secfrac) MUST NOT be included. This field | 2646 | | conforms to the date-time ABNF production from | 2647 | | section 5.6 of RFC 3339 with the above | 2648 | | restrictions. Leap seconds are permitted and | 2649 | | SWIMA-PVs MUST support them. The Timestamp | 2650 | | string MUST NOT be NULL terminated or padded in | 2651 | | any way. The length of this field is always 20 | 2652 | | octets. | 2653 | | | 2654 | Record | A 4-byte unsigned integer containing the Record | 2655 | Identifier | Identifier value from a software inventory | 2656 | | evidence record. | 2657 | | | 2658 | Data Model | A 3-byte unsigned integer containing the Private | 2659 | Type PEN | Enterprise Number (PEN) of the organization that | 2660 | | assigned the meaning of the Data Model Type | 2661 | | value. | 2662 | | | 2663 | Data Model | A 1-byte unsigned integer containing an | 2664 | Type | identifier number that identifies the data model | 2665 | | of the reported record. | 2666 | | | 2667 | Source | The Source Identification Number associated with | 2668 | Identification | the source from which this software installation | 2669 | Number | inventory instance was reported. | 2670 | | | 2671 | Action | The type of event that is recorded in this event | 2672 | | record. Possible values are: 1 = CREATION - the | 2673 | | addition of a record to the endpoint's Software | 2674 | | Inventory Evidence Collection; 2 = DELETION - | 2675 | | the removal of a record from the endpoint's | 2676 | | Software Inventory Evidence Collection; 3 = | 2677 | | ALTERATION - There was an alteration to a record | 2678 | | within the endpoint's Software Inventory | 2679 | | Evidence Collection. All other values are | 2680 | | reserved for future use and MUST NOT be used | 2681 | | when sending attributes. In the case where a | 2682 | | SWIMA-PV receives an event record that uses an | 2683 | | action value other than the ones defined here, | 2684 | | it MUST ignore that event record but SHOULD | 2685 | | process other event records in this attribute as | 2686 | | normal. | 2687 | | | 2688 | Software | A 2-byte unsigned integer indicating the length | 2689 | Identifier | in bytes of the SW ID field. | 2690 | Length | | 2691 | | | 2692 | Software | A string containing the Software Identifier | 2693 | Identifier | value from a software inventory evidence record. | 2694 | | This field value MUST first be normalized to | 2695 | | Network Unicode format as described in Section | 2696 | | 5.5. This string MUST NOT be NULL terminated. | 2697 | | | 2698 | Software | A 2-byte unsigned integer indicating the length | 2699 | Locator Length | in bytes of the Software Locator field. | 2700 | | | 2701 | Software | A string containing the Software Locator value. | 2702 | Locator | This field value MUST first be normalized to | 2703 | | Network Unicode format, as described in Section | 2704 | | 5.5, and then encoded as a URI [RFC3986]. This | 2705 | | string MUST NOT be NULL terminated. | 2706 +----------------+--------------------------------------------------+ 2708 Table 4: Software Identifier Events Attribute Fields 2710 The first few fields in the Software Identifier Events attribute 2711 mirror those in the Software Identifier Inventory attribute. The 2712 primary difference is that, instead of conveying an inventory, the 2713 attribute conveys zero or more event records, consisting of the EID, 2714 timestamp, Record Identifier, action type, data model type, Software 2715 Identifier, and Software Locator of the affected software inventory 2716 evidence record. 2718 With regard to the Timestamp field, it is important to note that 2719 clock skew between the SWIMA-PC and SWIMA-PV as well as between 2720 different SWIMA-PCs within an enterprise might make correlation of 2721 timestamp values difficult. This specification does not attempt to 2722 resolve clock skew issues, although other mechanisms outside of this 2723 specification do exist to reduce the impact of clock skew and make 2724 the timestamp more useful for such correlation. Instead, SWIMA uses 2725 the Timestamp value primarily as a means to indicate the amount of 2726 time between two events on a single endpoint. For example, by taking 2727 the difference of the times for when a record was removed and then 2728 subsequently re-added, one can get an indication as to how long the 2729 system was without the given record (and, thus without the associated 2730 software). Since this will involve comparison of timestamp values 2731 all originating on the same system, clock skew between the SWIMA-PC 2732 and SWIMA-PV is not an issue. However, if the SWIMA-PC's clock was 2733 adjusted between two recorded events, it is possible for such a 2734 calculation to lead to incorrect understandings of the temporal 2735 distance between events. Users of this field need to be aware of the 2736 possibility for such occurrences. In the case where the Timestamp 2737 values of two events appear to contradict the EID ordering of those 2738 events (i.e., the later EID has an earlier timestamp) the recipient 2739 MUST treat the EID ordering as correct. 2741 All events recorded in a Software Identifier Events Attribute are 2742 required to be part of the same EID Epoch. Specifically, all 2743 reported events MUST have an EID from the same EID Epoch as each 2744 other, and which is the same as the EID Epoch of the Last EID and 2745 Last Consulted EID values. The SWIMA-PC MUST NOT report events with 2746 EIDs from different EID Epochs. 2748 The Last Consulted EID field contains the EID of the last event 2749 record considered for inclusion in this attribute. If this attribute 2750 contains a partial event set (as described in Section 3.7.5) this 2751 field value will be less than the Last EID value; if this attribute 2752 contains a complete event set, the Last EID and Last Consulted EID 2753 values are identical. 2755 If multiple events are sent in a Software Identifier Events 2756 attribute, the order in which they appear within the attribute is not 2757 significant. The EIDs associated with them are used for ordering the 2758 indicated events appropriately. Also note that a single software 2759 record might be reported multiple times in an attribute, such as if 2760 multiple events involving the associated record were being reported. 2762 5.10. Software Inventory 2764 A SWIMA-PC sends this attribute to a SWIMA-PV to convey a list of 2765 inventory records. A SWIMA-PV MUST NOT send this attribute. The 2766 SWIMA-PC either sends this attribute in fulfillment of an existing 2767 subscription where the establishing request had a Result Type of 0 2768 and the Earliest EID is zero, or in direct response to a SWIMA 2769 Request attribute where the Result Type is 0 and the Earliest EID is 2770 zero. 2772 1 2 3 2773 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2774 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2775 | Flags | Record Count | 2776 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2777 | Request ID Copy / Subscription ID | 2778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2779 | EID Epoch | 2780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2781 | Last EID | 2782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2783 | | 2784 | SUB-BLOCK (Repeated "Record Count" times) | 2785 | | 2786 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2788 Figure 12: Software Inventory Attribute 2789 1 2 3 2790 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2792 | Record Identifier | 2793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2794 | Data Model Type PEN |Data Model Type| 2795 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2796 | Source Id Num | Software Identifier Length |Software Id (v)| 2797 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2798 | Software Locator Length |Software Locator (variable len)| 2799 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2800 | Record Length | 2801 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2802 | Record (variable length) | 2803 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2805 Figure 13: SWIMA Inventory Attribute SUB-BLOCK 2807 +----------------+--------------------------------------------------+ 2808 | Field | Description | 2809 +----------------+--------------------------------------------------+ 2810 | Flags: Bit 0 - | In the case that this attribute is sent in | 2811 | Subscription | fulfillment of a subscription this bit MUST be | 2812 | Fulfillment | set (1). In the case that this attribute is a | 2813 | | direct response to a SWIMA Request, this bit | 2814 | | MUST be unset (0). | 2815 | | | 2816 | Flags: Bit 1-7 | Reserved for future use. This field MUST be set | 2817 | - Reserved | to zero on transmission and ignored upon | 2818 | | reception. | 2819 | | | 2820 | Record Count | The number of records that follow. This field is | 2821 | | a 3-byte unsigned integer. The Record | 2822 | | Identifier, Data Model Type PEN, Data Model | 2823 | | Type, Source Identification Number, Software | 2824 | | Identifier Length, Software Identifier, Software | 2825 | | Locator Length, Software Locator, Record Length, | 2826 | | and Record fields are repeated, in order, the | 2827 | | number of times indicated in this field. This | 2828 | | field value MAY be 0 in which case there are no | 2829 | | instances of these fields. | 2830 | | | 2831 | Request ID | In the case where this attribute is in direct | 2832 | Copy / | response to a SWIMA Request attribute from a | 2833 | Subscription | SWIMA-PV, this field MUST contain an exact copy | 2834 | ID | of the Request ID field from that SWIMA Request. | 2835 | | In the case where this attribute is sent in | 2836 | | fulfillment of an active subscription, this | 2837 | | field MUST contain the Subscription ID of the | 2838 | | subscription being fulfilled by this attribute. | 2839 | | | 2840 | EID Epoch | The EID Epoch of the Last EID value. This field | 2841 | | is an unsigned 4-byte unsigned integer. | 2842 | | | 2843 | Last EID | The EID of the last event recorded by the SWIMA- | 2844 | | PC, or 0 if the SWIMA-PC has no recorded events. | 2845 | | This field is an unsigned 4-byte unsigned | 2846 | | integer. | 2847 | | | 2848 | Record | A 4-byte unsigned integer containing the Record | 2849 | Identifier | Identifier value from a software inventory | 2850 | | evidence record. | 2851 | | | 2852 | Data Model | A 3-byte unsigned integer containing the Private | 2853 | Type PEN | Enterprise Number (PEN) of the organization that | 2854 | | assigned the meaning of the Data Model Type | 2855 | | value. | 2856 | | | 2857 | Data Model | A 1-byte unsigned integer containing an | 2858 | Type | identifier number that identifies the data model | 2859 | | of the reported record. | 2860 | | | 2861 | Source | The Source Identification Number associated with | 2862 | Identification | the source from which this software installation | 2863 | Number | inventory instance was reported. | 2864 | | | 2865 | Software | A 2-byte unsigned integer indicating the length | 2866 | Identifier | in bytes of the SW ID field. | 2867 | Length | | 2868 | | | 2869 | Software | A string containing the Software Identifier | 2870 | Identifier | value from a software inventory evidence record. | 2871 | | This field value MUST first be normalized to | 2872 | | Network Unicode format as described in Section | 2873 | | 5.5. This string MUST NOT be NULL terminated. | 2874 | | | 2875 | Software | A 2-byte unsigned integer indicating the length | 2876 | Locator Length | in bytes of the Software Locator field. | 2877 | | | 2878 | Software | A string containing the Software Locator value. | 2879 | Locator | This field value MUST first be normalized to | 2880 | | Network Unicode format, as described in Section | 2881 | | 5.5, and then encoded as a URI [RFC3986]. This | 2882 | | string MUST NOT be NULL terminated. | 2883 | | | 2884 | Record Length | This is a 4-byte unsigned integer indicating the | 2885 | | length of the Record field in bytes. | 2886 | | | 2887 | Record | A software inventory evidence record as a | 2888 | | string. The record MUST be converted and | 2889 | | normalized to Network Unicode format as | 2890 | | described in Section 5.5. This string MUST NOT | 2891 | | be NULL terminated. | 2892 +----------------+--------------------------------------------------+ 2894 Table 5: Software Inventory Attribute Fields 2896 The Software Inventory attribute contains some number of software 2897 inventory evidence records along with the core response attribute 2898 fields. Given that the size of records can vary considerably, the 2899 length of this attribute is highly variable and, if transmitting a 2900 complete inventory, can be extremely large. Enterprises might wish 2901 to constrain the use of Software Inventory attributes to targeted 2902 requests to avoid over-burdening the network unnecessarily. 2904 When copying a software inventory evidence record into the Record 2905 field, the record MUST be converted and normalized to use Network 2906 Unicode format prior to its inclusion in the record field. 2908 5.11. Software Events 2910 A SWIMA-PC sends this attribute to a SWIMA-PV to convey a list of 2911 events that include software inventory evidence records. A SWIMA-PV 2912 MUST NOT send this attribute. The SWIMA-PC either sends this 2913 attribute in fulfillment of an existing subscription where the 2914 establishing request has a Result Type of 0 and the Earliest EID is 2915 non-zero, or in direct response to a SWIMA Request attribute where 2916 the Result Type is 0 and the Earliest EID is non-zero. 2918 1 2 3 2919 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2920 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2921 | Flags | Event Count | 2922 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2923 | Request ID Copy / Subscription ID | 2924 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2925 | EID Epoch | 2926 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2927 | Last EID | 2928 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2929 | Last Consulted EID | 2930 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2931 | | 2932 | SUB-BLOCK (Repeated "Event Count" times) | 2933 | | 2934 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2936 Figure 14: Software Events Attribute 2937 1 2 3 2938 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2939 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2940 | EID | 2941 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2942 | | 2943 +- -+ 2944 | | 2945 +- -+ 2946 | Timestamp | 2947 +- -+ 2948 | | 2949 +- -+ 2950 | | 2951 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2952 | Record Identifier | 2953 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2954 | Data Model Type PEN |Data Model Type| 2955 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2956 | Source Id Num | Action | Software Identifier Length | 2957 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2958 | Software Identifier (variable length) | 2959 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2960 | Software Locator Length |Software Locator (variable len)| 2961 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2962 | Record Length | 2963 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2964 | Record (variable Length) | 2965 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2967 Figure 15: SWIMA Events Attribute SUB-BLOCK 2969 +----------------+--------------------------------------------------+ 2970 | Field | Description | 2971 +----------------+--------------------------------------------------+ 2972 | Flags: Bit 0 - | In the case that this attribute is sent in | 2973 | Subscription | fulfillment of a subscription this bit MUST be | 2974 | Fulfillment | set (1). In the case that this attribute is a | 2975 | | direct response to a SWIMA Request, this bit | 2976 | | MUST be unset (0). | 2977 | | | 2978 | Flags: Bit 1-7 | Reserved for future use. This field MUST be set | 2979 | - Reserved | to zero on transmission and ignored upon | 2980 | | reception. | 2981 | | | 2982 | Event Count | The number of events being reported in this | 2983 | | attribute. This field is a 3-byte unsigned | 2984 | | integer. The EID, Timestamp, Record Identifier, | 2985 | | Data Model Type PEN, Data Model Type, Source | 2986 | | Identification Number, Action, Software | 2987 | | Identifier Length, Software Identifier, Software | 2988 | | Locator Length, Software Locator, Record Length, | 2989 | | and Record fields are repeated, in order, the | 2990 | | number of times indicated in this field. This | 2991 | | field value MAY be 0, in which case there are no | 2992 | | instances of these fields. | 2993 | | | 2994 | Request ID | In the case where this attribute is in direct | 2995 | Copy / | response to a SWIMA Request attribute from a | 2996 | Subscription | SWIMA-PV, this field MUST contain an exact copy | 2997 | ID | of the Request ID field from that SWIMA Request. | 2998 | | In the case where this attribute is sent in | 2999 | | fulfillment of an active subscription, this | 3000 | | field MUST contain the Subscription ID of the | 3001 | | subscription being fulfilled by this attribute. | 3002 | | | 3003 | EID Epoch | The EID Epoch of the Last EID value. This field | 3004 | | is an unsigned 4-byte unsigned integer. | 3005 | | | 3006 | Last EID | The EID of the last event recorded by the SWIMA- | 3007 | | PC, or 0 if the SWIMA-PC has no recorded events. | 3008 | | This field contains the EID of the SWIMA-PC's | 3009 | | last recorded change event (which might or might | 3010 | | not be included as an event record in this | 3011 | | attribute). | 3012 | | | 3013 | Last Consulted | The EID of the last event record that was | 3014 | EID | consulted when generating the event record list | 3015 | | included in this attribute. This is different | 3016 | | from the Last EID field value if and only if | 3017 | | this attribute is conveying a partial list of | 3018 | | event records. See Section 3.7.5 for more on | 3019 | | partial list of event records. | 3020 | | | 3021 | EID | The EID of the event in this event record. | 3022 | | | 3023 | Timestamp | The timestamp associated with the event in this | 3024 | | event record. This timestamp is the SWIMA-PC's | 3025 | | best understanding of when the given event | 3026 | | occurred. Note that this timestamp might be an | 3027 | | estimate. The Timestamp date and time MUST be | 3028 | | represented as an RFC 3339 [RFC3339] compliant | 3029 | | ASCII string in Coordinated Universal Time (UTC) | 3030 | | time with the additional restrictions that the | 3031 | | 'T' delimiter and the 'Z' suffix MUST be | 3032 | | capitalized and fractional seconds (time- | 3033 | | secfrac) MUST NOT be included. This field | 3034 | | conforms to the date-time ABNF production from | 3035 | | section 5.6 of RFC 3339 with the above | 3036 | | restrictions. Leap seconds are permitted and | 3037 | | SWIMA-PVs MUST support them. The Timestamp | 3038 | | string MUST NOT be NULL terminated or padded in | 3039 | | any way. The length of this field is always 20 | 3040 | | octets. | 3041 | | | 3042 | Record | A 4-byte unsigned integer containing the Record | 3043 | Identifier | Identifier value from a software inventory | 3044 | | evidence record. | 3045 | | | 3046 | Data Model | A 3-byte unsigned integer containing the Private | 3047 | Type PEN | Enterprise Number (PEN) of the organization that | 3048 | | assigned the meaning of the Data Model Type | 3049 | | value. | 3050 | | | 3051 | Data Model | A 1-byte unsigned integer containing an | 3052 | Type | identifier number that identifies the data model | 3053 | | of the reported record. | 3054 | | | 3055 | Source | The Source Identification Number associated with | 3056 | Identification | the source from which this software installation | 3057 | Number | inventory instance was reported. | 3058 | | | 3059 | Action | The type of event that is recorded in this event | 3060 | | record. Possible values are: 1 = CREATION - the | 3061 | | addition of a record to the endpoint's Software | 3062 | | Inventory Evidence Collection; 2 = DELETION - | 3063 | | the removal of a record from the endpoint's | 3064 | | Software Inventory Evidence Collection; 3 = | 3065 | | ALTERATION - There was an alteration to a record | 3066 | | within the endpoint's Software Inventory | 3067 | | Evidence Collection. All other values are | 3068 | | reserved for future use and MUST NOT be used | 3069 | | when sending attributes. In the case where a | 3070 | | SWIMA-PV receives an event record that uses an | 3071 | | action value other than the ones defined here, | 3072 | | it MUST ignore that event record but SHOULD | 3073 | | process other event records in this attribute as | 3074 | | normal. | 3075 | | | 3076 | Software | A 2-byte unsigned integer indicating the length | 3077 | Identifier | in bytes of the Software Identifier field. | 3078 | Length | | 3079 | | | 3080 | Software | A string containing the Software Identifier | 3081 | Identifier | value from a software inventory evidence record. | 3082 | | This field value MUST first be normalized to | 3083 | | Network Unicode format as described in Section | 3084 | | 5.5. This string MUST NOT be NULL terminated. | 3085 | | | 3086 | Software | A 2-byte unsigned integer indicating the length | 3087 | Locator Length | in bytes of the Software Locator field. | 3088 | | | 3089 | Software | A string containing the Software Locator value. | 3090 | Locator | This field value MUST first be normalized to | 3091 | | Network Unicode format, as described in Section | 3092 | | 5.5, and then encoded as a URI [RFC3986]. This | 3093 | | string MUST NOT be NULL terminated. | 3094 | | | 3095 | Record Length | This is a 4-byte unsigned integer indicating the | 3096 | | length of the Record field in bytes. | 3097 | | | 3098 | Record | A software inventory evidence record as a | 3099 | | string. The record MUST be converted and | 3100 | | normalized to Network Unicode format as | 3101 | | described in Section 5.5. This string MUST NOT | 3102 | | be NULL terminated. | 3103 +----------------+--------------------------------------------------+ 3105 Table 6: Software Events Attribute Fields 3107 The fields of this attribute are used in the same way as the 3108 corresponding fields of the previous attributes. As with the 3109 Software Inventory attribute, a Software Events attribute can be 3110 quite large if many events have occurred following the event 3111 indicated by a request's Earliest EID. As such, it is recommended 3112 that the SWIMA Request attributes only request full records be sent 3113 (Result Type set to 0) in a targeted request, thus constraining the 3114 response just to records that match a given set of Software 3115 Identifiers. 3117 As with the Software Identifier Events Attribute, this attribute MUST 3118 only contain event records with EIDs coming from the current EID 3119 Epoch of the SWIMA-PC. 3121 As with the Software Inventory Attribute, the SWIMA-PC MUST perform 3122 conversion and normalization of the record. 3124 5.12. Subscription Status Request 3126 A SWIMA-PV sends this attribute to a SWIMA-PC to request a list of 3127 active subscriptions for which the requesting SWIMA-PV is the 3128 subscriber. A SWIMA-PC MUST NOT send this attribute. 3130 This attribute has no fields. 3132 A SWIMA-PC MUST respond to this attribute by sending a Subscription 3133 Status Response attribute (or a PA-TNC Error attribute if it is 3134 unable to correctly provide a response). 3136 5.13. Subscription Status Response 3138 A SWIMA-PC sends this attribute to a SWIMA-PV to report the list of 3139 active subscriptions for which the receiving SWIMA-PV is the 3140 subscriber. A SWIMA-PV MUST NOT send this attribute. 3142 1 2 3 3143 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3145 | Status Flags | Subscription Record Count | 3146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3147 | | 3148 | SUB-BLOCK (Repeated "Subscription Record Count" times) | 3149 | | 3150 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3152 Figure 16: Subscription Status Response Attribute 3154 1 2 3 3155 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3157 | Flags | Software Identifier Count | 3158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3159 | Request ID | 3160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3161 | Earliest EID | 3162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3163 | | 3164 | SUB-SUB-BLOCK (Repeated "Software Identifier Count" times) | 3165 | | 3166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3168 Figure 17: SWIMA Status Response Attribute SUB-BLOCK 3169 1 2 3 3170 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3172 | Software Identifier Length | Software Identifier (var len) | 3173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3175 Figure 18: SWIMA Status Response Attribute SUB-SUB-BLOCK 3177 +--------------+----------------------------------------------------+ 3178 | Field | Description | 3179 +--------------+----------------------------------------------------+ 3180 | Status | Reserved for future use. This field MUST be set to | 3181 | Flags: Bit | zero on transmission and ignored upon reception. | 3182 | 0-7 - | | 3183 | Reserved | | 3184 | | | 3185 | Subscription | The number of subscription records that follow. | 3186 | Record Count | This field is a 3-byte unsigned integer. The | 3187 | | Flags, Software Identifier Count, Request ID, and | 3188 | | Earliest EID fields, and 0 or more instances of | 3189 | | Software Identifier Length and Software | 3190 | | Identifier, are repeated, in order, the number of | 3191 | | times indicated in this field. (The Software | 3192 | | Identifier Length and Software Identifier fields | 3193 | | within each of these sets of fields are repeated a | 3194 | | number of times equal to the preceding Software | 3195 | | Identifier Count value.) The Subscription Record | 3196 | | Count field value MAY be 0 in which case there are | 3197 | | no instances of these fields. | 3198 | | | 3199 | Flags, | For each active subscription, these fields contain | 3200 | Software | an exact copy of the fields with the same name as | 3201 | Identifier | provided in the subscription's establishing | 3202 | Count, | request. | 3203 | Request ID, | | 3204 | Earliest | | 3205 | EID, | | 3206 | Software | | 3207 | Identifier | | 3208 | Length, and | | 3209 | Software | | 3210 | Identifier | | 3211 +--------------+----------------------------------------------------+ 3213 Table 7: Subscription Status Response Fields 3215 A Subscription Status Response contains zero or more subscription 3216 records. Specifically, it MUST contain one subscription record for 3217 each active subscription associated with the party that sent the 3218 Subscription Status Request to which this attribute is a response. 3219 As described in Section 3.8.2, the SWIMA-PC MUST use the requester's 3220 Connection ID and its Posture Validator ID to determine which 3221 subscriptions are associated with the requester. 3223 A SWIMA-PC MUST send a Subscription Status Response attribute in 3224 response to a Subscription Status Request attribute. The only 3225 exception to this is if the SWIMA-PC experiences an error condition 3226 that prevents it from correctly populating the Subscription Status 3227 Response attribute, in which case it MUST respond with a PA-TNC Error 3228 attribute appropriate to the type of error experienced. If there are 3229 no active subscriptions associated with the requesting party, the 3230 Subscription Status Response attribute will consist of its Status 3231 Flags field, a Subscription Record Count field with a value of 0, and 3232 no additional fields. 3234 Each subscription record included in a Subscription Status Response 3235 attribute duplicates the fields of a SWIMA Request attribute that was 3236 the establishing request of a subscription. Note that the Request ID 3237 field in the record captures the Subscription ID associated with the 3238 given subscription record (since the Subscription ID is the same as 3239 the Request ID of the establishing request). Note also that if the 3240 establishing request is targeted, then its Record Count field will be 3241 non-zero and, within that subscription record, the Software 3242 Identifier Length and Software Identifier fields are repeated, in 3243 order, the number of times indicated in the Record Count field. As 3244 such, each subscription record can be different sizes. If the 3245 establishing request is not targeted (Record Count field is 0), the 3246 subscription record has no Software Identifier Length or Software 3247 Identifier fields. 3249 When a SWIMA-PV compares the information received in a Subscription 3250 Status Response to its own records of active subscriptions it should 3251 be aware that the SWIMA-PC might be unable to distinguish this SWIMA- 3252 PV from other SWIMA-PVs on the same NEA Server. As a result, it is 3253 possible that the SWIMA-PC will report more subscription records than 3254 the SWIMA-PV recognizes. For this reason, SWIMA-PVs SHOULD NOT 3255 automatically assume that extra subscriptions reported in a 3256 Subscription Status Response indicate a problem. 3258 5.14. Source Metadata Request 3260 A SWIMA-PV sends this attribute to a SWIMA-PC to request metadata 3261 about sources that the SWIMA-PC is using to collect software 3262 inventory information. A SWIMA-PC MUST NOT send this attribute. 3264 This attribute has no fields. 3266 A SWIMA-PC MUST respond to this attribute by sending a Sources 3267 Metadata Response attribute (or a PA-TNC Error attribute if it is 3268 unable to correctly provide a response). 3270 5.15. Source Metadata Response 3272 A SWIMA-PC sends this attribute to a SWIMA-PV to provide descriptive 3273 metadata about the sources of software inventory information used by 3274 the SWIMA-PC. A SWIMA-PV MUST NOT send this attribute. 3276 1 2 3 3277 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3279 | Reserved | Source Count | | 3280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 3281 | | 3282 | SUB-BLOCK (Repeated "Source Count" times | 3283 | | 3284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3286 Source Metadata Response Attribute 3288 1 2 3 3289 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3291 | Source ID | Metadata Length | Metadata (var)| 3292 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3294 Source Metadata Response Attribute SUB-BLOCK 3296 +----------+--------------------------------------------------------+ 3297 | Field | Description | 3298 +----------+--------------------------------------------------------+ 3299 | Reserved | Reserved for future use. This field MUST be set to | 3300 | | zero on transmission and ignored upon reception. | 3301 | | | 3302 | Source | The number of source records that follow. The Source | 3303 | Count | ID, Metadata Size, and Metadata fields are repeated, | 3304 | | in order, the number of times indicated by this field. | 3305 | | This field MAY be 0, in which case no fields follow | 3306 | | (but this would only be done to indicate that the | 3307 | | SWIMA-PC has no active sources, which would not be a | 3308 | | usual situation). | 3309 | | | 3310 | Source | The Source ID number associated with the described | 3311 | ID | source for any communications with the recipient | 3312 | | SWIMA-PV. | 3313 | | | 3314 | Metadata | A 2-byte unsigned integer indicating the length in | 3315 | Length | bytes of the Metadata field. | 3316 | | | 3317 | Metadata | A string containing descriptive metadata about the | 3318 | | indicated data source. This string MUST NOT be NULL | 3319 | | terminated. | 3320 +----------+--------------------------------------------------------+ 3322 Source Metadata Response Fields 3324 A Source Metadata Response attribute contains 0 or more records, each 3325 describing one of the data sources the SWIMA-PC uses to collect 3326 software inventory information. It SHOULD contain one metadata 3327 record for each source that the SWIMA-PC uses. (There might be 3328 reasons not to inform certain SWIMA-PVs of the presence of certain 3329 data sources.) The attribute MUST contain a metadata record for each 3330 source that has been identified in inventory or event messages to the 3331 given SWIMA-PV. 3333 A SWIMA-PC MUST send a Source Metadata Response attribute in response 3334 to a Source Metadata Request attribute. The only exception to this 3335 is if the SWIMA-PC experiences an error condition that prevents it 3336 from correctly populating the Source Metadata Response attribute, in 3337 which case it MUST respond with a PA-TNC Error attribute appropriate 3338 to the type of error experienced. 3340 The Source Count field indicates how many source metadata records are 3341 included in the attribute. Each included record consists of a Source 3342 Identifier, Metadata Length, and Metadata field. 3344 The Source Identifier corresponds to the Source Identifier field in 3345 inventory and event messages. In the case where the Source 3346 Identifier value in a Source Metadata Response attribute matches a 3347 Source Identifier associated with an event or inventory record and 3348 both the Source Metadata Response and the inventory/event record were 3349 sent to the same SWIMA-PV, the source described in the Metadata field 3350 MUST be the same source that provided the event or inventory record 3351 associated with the Source Identifier. Recall that a SWIMA-PC MAY 3352 use different Source Identifier associations with different SWIMA- 3353 PVs. As such, the association between a Source Identifier and the 3354 conveyed metadata is also only meaningful for communications between 3355 the sending SWIMA-PC and receiving SWIMA-PV. When sending to a given 3356 SWIMA-PV, the SWIMA-PC MUST use the recipient SWIMA-PVs Source 3357 Identifier associations. 3359 The Metadata Length indicates the length, in bytes, if the Metadata 3360 field. The Metadata field contains information about the indicated 3361 data source. This specification does not dictate a format for the 3362 contents of the Metadata field. This field MAY include machine- 3363 readable information. For broadest utility, the Metadata field 3364 SHOULD include human-readable, descriptive information about the data 3365 source. 3367 5.16. PA-TNC Error as Used by SWIMA 3369 The PA-TNC Error attribute is defined in the PA-TNC specification 3370 [RFC5792], and its use here conforms to that specification. A PA-TNC 3371 Error can be sent due to any error in the PA-TNC exchange and might 3372 also be sent in response to error conditions specific to the SWIMA 3373 exchange. The latter case utilizes error codes defined below. 3375 A PA-TNC Error MUST be sent by a SWIMA-PC in response to a SWIMA 3376 Request in the case where the SWIMA-PC encounters a fatal error 3377 (i.e., an error that prevents further processing of an exchange) 3378 relating to the attribute exchange. A SWIMA-PV MUST NOT send this 3379 attribute. In the case where the SWIMA-PV experiences a fatal error, 3380 it MUST handle the error without sending a PA-TNC Error attribute. 3381 The SWIMA-PV MAY take other actions in response to the error, such as 3382 logging the cause of the error, or even taking actions to isolate the 3383 endpoint. 3385 A PA-TNC Error attribute is sent instead of a SWIMA Response 3386 attribute due to factors that prevent the reliable creation of a 3387 SWIMA Response. As such, a SWIMA-PC MUST NOT send both a PA-TNC 3388 Error attribute and a SWIMA Response attribute in response to a 3389 single SWIMA Request attribute. 3391 Table 8 lists the Error Code values for the PA-TNC Error attribute 3392 specific to the SWIMA exchange. Error codes are shown in both 3393 hexadecimal and decimal format. In all of these cases, the Error 3394 Code Vendor ID field MUST be set to 0x000000, corresponding to the 3395 IETF SMI Private Enterprise Number. The Error Information structures 3396 for each error type are described in the following subsections. 3398 Note that a message with a SWIMA attribute might also result in an 3399 error condition covered by the Standard PA-TNC Error Codes defined in 3400 PA-TNC. For example, a SWIMA Attribute might have an invalid 3401 parameter, leading to an error code of "Invalid Parameter". In this 3402 case, the SWIMA-PC MUST use the appropriate PA-TNC Error Code value 3403 as defined in Section 4.2.8 of PA-TNC specification. 3405 +------------+------------------------------------------------------+ 3406 | Error Code | Description | 3407 | Value | | 3408 +------------+------------------------------------------------------+ 3409 | 0x00000004 | SWIMA_ERROR. This indicates a fatal error (i.e., an | 3410 | (4) | error that precludes the creation of a suitable | 3411 | | response attribute) other than the errors described | 3412 | | below but still specific to the processing of SWIMA | 3413 | | Attributes. The Description field SHOULD contain | 3414 | | additional diagnostic information. | 3415 | | | 3416 | 0x00000005 | SWIMA_SUBSCRIPTION_DENIED_ERROR. This indicates that | 3417 | (5) | the SWIMA-PC denied the SWIMA-PV's request to | 3418 | | establish a subscription. The Description field | 3419 | | SHOULD contain additional diagnostic information. | 3420 | | | 3421 | 0x00000006 | SWIMA_RESPONSE_TOO_LARGE_ERROR. This indicates that | 3422 | (6) | the SWIMA-PC's response to the SWIMA-PV's request | 3423 | | was too large to be serviced. The error information | 3424 | | structure indicates the largest possible size of a | 3425 | | response supported by the SWIMA-PC (see Section | 3426 | | 5.16.2). The Description field SHOULD contain | 3427 | | additional diagnostic information. | 3428 | | | 3429 | 0x00000007 | SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR. This indicates | 3430 | (7) | that the SWIMA-PC experienced an error fulfilling a | 3431 | | given subscription. The error information includes | 3432 | | the Subscription ID of the relevant subscription, as | 3433 | | well as a sub-error that describes the nature of the | 3434 | | error the SWIMA-PC experienced. The SWIMA-PC and | 3435 | | SWIMA-PV MUST treat the identified subscription as | 3436 | | cancelled. | 3437 | | | 3438 | 0x00000008 | SWIMA_SUBSCRIPTION_ID_REUSE_ERROR. This indicates | 3439 | (8) | that the SWIMA-PC received a SWIMA Request from a | 3440 | | given SWIMA-PV where the Request ID of that SWIMA | 3441 | | Request is currently used as the Subscription ID of | 3442 | | an active subscription with that SWIMA-PV. This | 3443 | | error does not cancel the identified subscription. | 3444 +------------+------------------------------------------------------+ 3446 Table 8: PA-TNC Error Codes for SWIMA 3448 The following subsections describe the structures present in the 3449 Error Information fields. Note that all error structures include a 3450 variable-length field, but do not include any fields indicating the 3451 length of those fields. Such a field is unnecessary because all 3452 other fields in the PA-TNC Error attribute are fixed-length, and thus 3453 the length of the variable-length field can be found by subtracting 3454 the size of these fixed-length fields from the PA-TNC Attribute 3455 Length field in the PA-TNC Attribute Header. 3457 5.16.1. SWIMA_ERROR, SWIMA_SUBSCRIPTION_DENIED_ERROR and 3458 SWIMA_SUBSCRIPTION_ID_REUSE_ERROR Information 3460 The SWIMA_ERROR error code indicates that the sender (the SWIMA-PC) 3461 has encountered an error related to the processing of a SWIMA Request 3462 attribute but which is not covered by more specific SWIMA error 3463 codes. The SWIMA_SUBSCRIPTION_DENIED_ERROR is used when the SWIMA-PV 3464 requests to establish a subscription or clear all subscriptions from 3465 the given SWIMA-PV, but the SWIMA-PC is unable or unwilling to comply 3466 with this request. The SWIMA_SUBSCRIPTION_ID_REUSE_ERROR is used 3467 when the SWIMA-PC receives a SWIMA Request whose Request ID 3468 duplicates a Subscription ID of an active subscription with the 3469 request's sender. All of these error codes use the following error 3470 information structure. 3472 1 2 3 3473 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3474 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3475 | Copy of Request ID / Subscription ID | 3476 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3477 | Description (variable length) | 3478 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3480 Figure 19: SWIMA Error, Subscription Error, and Subscription ID Reuse 3481 Information 3483 +--------------+----------------------------------------------------+ 3484 | Field | Description | 3485 +--------------+----------------------------------------------------+ 3486 | Copy of | In the case that this error condition is generated | 3487 | Request ID / | in direct response to a SWIMA Request attribute, | 3488 | Subscription | this field MUST contain an exact copy of the | 3489 | ID | Request ID field in the SWIMA Request attribute | 3490 | | that caused this error. In the case that the | 3491 | | attribute in question is generated in fulfillment | 3492 | | of an active subscription, this field MUST contain | 3493 | | the Subscription ID of the subscription for which | 3494 | | the attribute was generated. (This is only | 3495 | | possible if the error code is SWIMA_ERROR as the | 3496 | | other errors are not generated by subscription | 3497 | | fulfillment.) Note that, in this case, the | 3498 | | indicated error appears as a sub-error for a | 3499 | | SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR, as described | 3500 | | in Section 5.16.3. | 3501 | | | 3502 | Description | A UTF-8 [RFC3629] string describing the condition | 3503 | | that caused this error. This field MAY be | 3504 | | 0-length. However, senders SHOULD include some | 3505 | | description in all PA-TNC Error attributes of | 3506 | | these types. This field MUST NOT be NULL | 3507 | | terminated. | 3508 +--------------+----------------------------------------------------+ 3510 Table 9: SWIMA Error, Subscription Error, and Subscription ID Reuse 3511 Information Fields 3513 This error information structure is used with SWIMA_ERROR, 3514 SWIMA_SUBSCRIPTION_DENIED_ERROR, and 3515 SWIMA_SUBSCRIPTION_ID_REUSE_ERROR status codes to identify the SWIMA 3516 Request attribute that precipitated the error condition and to 3517 describe the error. The Description field contains text describing 3518 the error. The SWIMA-PC MAY encode machine-interpretable information 3519 in this field, but SHOULD also include a human-readable description 3520 of the error, since the receiving SWIMA-PV might not recognize the 3521 SWIMA-PC's encoded information. 3523 5.16.2. SWIMA_RESPONSE_TOO_LARGE_ERROR Information 3525 The SWIMA_RESPONSE_TOO_LARGE_ERROR error code indicates that a 3526 response generated by a SWIMA-PC in response to a SWIMA-PV's SWIMA 3527 Request attribute was too large to send. 3529 1 2 3 3530 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3532 | Copy of Request ID / Subscription I | 3533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3534 | Maximum Allowed Size | 3535 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3536 | Description (variable length) | 3537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3539 Figure 20: SWIMA Response Too Large Error Information 3541 +--------------+----------------------------------------------------+ 3542 | Field | Description | 3543 +--------------+----------------------------------------------------+ 3544 | Copy of | In the case that the attribute in question is | 3545 | Request ID / | generated in direct response to a SWIMA Request, | 3546 | Subscription | this field MUST contain an exact copy of the | 3547 | ID | Request ID field in the SWIMA Request attribute | 3548 | | that caused this error. In the case that the | 3549 | | attribute in question is generated in fulfillment | 3550 | | of an active subscription, this field MUST contain | 3551 | | the Subscription ID of the subscription for which | 3552 | | the attribute was generated. Note that, in the | 3553 | | latter case, the SWIMA_RESPONSE_TOO_LARGE_ERROR | 3554 | | appears as a sub-error for a | 3555 | | SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR, as described | 3556 | | in Section 5.16.3. | 3557 | | | 3558 | Maximum | This field MUST contain an unsigned integer | 3559 | Allowed Size | indicating the largest permissible size, in bytes, | 3560 | | of SWIMA Attribute that the SWIMA-PC is currently | 3561 | | willing to send in response to a SWIMA Request | 3562 | | attribute. | 3563 | | | 3564 | Description | A UTF-8 [RFC3629] string describing the condition | 3565 | | that caused this error. This field MAY be | 3566 | | 0-length. However, senders SHOULD include some | 3567 | | description in all PA-TNC Error attributes of | 3568 | | these types. This field MUST NOT be NULL | 3569 | | terminated. | 3570 +--------------+----------------------------------------------------+ 3572 Table 10: SWIMA Response Too Large Error Information Fields 3574 This error structure is used with the SWIMA_RESPONSE_TOO_LARGE_ERROR 3575 status code to identify the SWIMA Request attribute that precipitated 3576 the error condition and to describe the error. The Maximum Allowed 3577 Size field indicates the largest attribute the SWIMA-PC is willing to 3578 send in response to a SWIMA Request under the current circumstances. 3579 Note that under other circumstances, the SWIMA-PC might be willing to 3580 return larger or smaller responses than indicated (such as if the 3581 endpoint connects to the NEA Server using a different network 3582 protocol). The other fields in this error information structure have 3583 the same meanings as corresponding fields in the SWIMA_ERROR and 3584 SWIMA_SUBSCRIPTION_DENIED_ERROR information structure. 3586 5.16.3. SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR Information 3588 The SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR error code indicates that 3589 the SWIMA-PC encountered an error while fulfilling a subscription. 3590 The bytes after the first 4 octets duplicate a PA-TNC Error attribute 3591 (as described in Section 4.2.8 of PA-TNC) that is used to identify 3592 the nature of the encountered error. 3594 1 2 3 3595 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 3596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3597 | Subscription ID | 3598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3599 | Reserved | Sub Error Code Vendor ID | 3600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3601 | Sub Error Code | 3602 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3603 | Sub Error Information (variable Length) | 3604 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3606 Figure 21: SWIMA Subscription Fulfillment Error Information 3608 +--------------+----------------------------------------------------+ 3609 | Field | Description | 3610 +--------------+----------------------------------------------------+ 3611 | Subscription | This field MUST contain the Subscription ID of the | 3612 | ID | subscription whose fulfillment caused this error. | 3613 | | | 3614 | Reserved | This field MUST contain the value of the Reserved | 3615 | | field of a PA-TNC Error attribute that describes | 3616 | | the error condition encountered during | 3617 | | subscription processing. | 3618 | | | 3619 | Sub Error | This field MUST contain the value of the Error | 3620 | Code Vendor | Code Vendor ID field of a PA-TNC Error attribute | 3621 | ID | that describes the error condition encountered | 3622 | | during subscription processing. | 3623 | | | 3624 | Sub Error | This field MUST contain the value of the Error | 3625 | Code | Code field of a PA-TNC Error attribute that | 3626 | | describes the error condition encountered during | 3627 | | subscription processing. | 3628 | | | 3629 | Sub Error | This field MUST contain the value of the Error | 3630 | Information | Information field of a PA-TNC Error attribute that | 3631 | | describes the error condition encountered during | 3632 | | subscription processing. | 3633 +--------------+----------------------------------------------------+ 3635 Table 11: SWIMA Subscription Fulfillment Error Information Fields 3637 This error structure is used with the 3638 SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR status code. The first 4 octets 3639 of this error structure contain the Subscription ID of the 3640 subscription that was being fulfilled when the error occurred. The 3641 remaining fields of this error structure duplicate the fields of a 3642 PA-TNC Error attribute, referred to as the "sub-error". The error 3643 code of the sub-error corresponds to the type of error that the 3644 SWIMA-PC encountered while fulfilling the given subscription. The 3645 sub-error MUST NOT have an error code of 3646 SWIMA_SUBSCRIPTION_FULFILLMENT_ERROR. 3648 The SWIMA-PC sending a PA-TNC Error attribute with this error code, 3649 and the SWIMA-PV receiving it, MUST treat the subscription identified 3650 by the Subscription ID field as cancelled. All other subscriptions 3651 are unaffected. 3653 6. Supported Data Models 3655 SWIMA supports an extensible list of data models for representing and 3656 transmitting software inventory information. This list of data 3657 models appears in the Software Data Model IANA registry (see 3658 Section 10.4). This document provides guidance for an initial set of 3659 data models. Other documents might provide guidance on the use of 3660 new data models by SWIMA, and will be referenced by extensions to the 3661 Software Data Model IANA registry. 3663 6.1. ISO 2015 SWID Tags using XML 3665 The International Organization for Standardization and the 3666 International Electrotechnical Commission (ISO/IEC) published the 3667 specification governing SWID tag construction and use in 2009 with a 3668 revised version published in 2015. [SWID15] Since that time, a 3669 growing number of vendors have integrated SWID tags into their 3670 software products. Doing so significantly simplifies the task of 3671 identifying these pieces of software: instead of relying on discovery 3672 processes that look for clues as to software presence, such as the 3673 presence of particular files or registry keys. A readily available 3674 list of SWID tags provides simple and immediate evidence as to the 3675 presence of the given piece of software. 3677 SWIMA has no reliance on the presence or management of SWID tags on 3678 an endpoint as described in the ISO specification. However, the data 3679 model for describing software that is presented in the ISO 3680 specification provides a robust and comprehensive way of describing 3681 software and is adopted here as a means of representing and 3682 transmitting software information. It should be emphasized, the use 3683 of the ISO SWID tag data model makes no assumption as to whether the 3684 source of the recorded information was, in fact, an ISO SWID tag 3685 harvested from the endpoint or whether the information was created 3686 using some other source and normalized to the SWID format. 3688 6.1.1. Guidance on Normalizing Source Data to ISO 2015 SWID Tags using 3689 XML 3691 Any record associated with this Software Data Model Type MUST conform 3692 to the ISO/IEC 19770-2-2015 [SWID15] specification. 3694 If generating a new ISO 2015 SWID tag, the software generating the 3695 tag MUST use a Tag Creator RegID that is associated with the 3696 generating software, unless this is impossible, in which case it MUST 3697 use the "http://invalid.unavailable" Tag Creator RegID value. (This 3698 conforms to conventions for an unknown Tag Creator in the ISO 2015 3699 SWID tag specification.) Do not use a RegID associated with any 3700 other party. In particular, it is incorrect to use a Tag Creator 3701 RegID associated with the software being described by the tag, the 3702 enterprise that is using the software, or any other entity except 3703 that of the party that built the tool that is generating the SWID 3704 tag. This reflects the requirement that the Tag Creator RegID 3705 identify the party that created the tag. Moreover, any generated 3706 tags SHOULD conform with guidance for tag creators provided NIST IR 3707 8060 [NIST8060], which provides additional recommendations to 3708 increase interoperable use of SWID tags. 3710 6.1.2. Guidance on Creation of Software Identifiers from ISO 2015 SWID 3711 Tags 3713 A Software Identifier generated from an ISO 2015 SWID tag is 3714 expressed as a concatenation of the value of the Tag Creator RegID 3715 field and the Unique ID field. Specifically, it MUST be of the form: 3716 TAG_CREATOR_REGID "_" "_" UNIQUE_ID. Specifically, the Software 3717 Identifier consists of, the Tag Creator RegID and the Unique ID from 3718 the tag connected with a double underscore (_), without any other 3719 connecting character or whitespace. 3721 6.2. ISO 2009 SWID Tags using XML 3723 As noted above, ISO's SWID tag specification provides a useful data 3724 model for representation of software information. As of the writing 3725 of this specification, while the 2015 specification is considered 3726 more comprehensive and addresses some issues with the 2009 3727 specification, 2009-format SWID tags remain far more common in 3728 deployments. For this reason, ISO 2009 SWID tags are included in the 3729 Software Data Model IANA table. 3731 6.2.1. Guidance on Normalizing Source Data to ISO 2009 SWID Tags using 3732 XML 3734 Any record associated with this Software Data Model Type MUST conform 3735 to the ISO/IEC 19770-2-2009 [SWID09] specification. Any such tag 3736 SHOULD use a UTF-8 encoding [RFC3629], but MUST NOT alter the 3737 existing encoding if doing so would invalidate digital signatures 3738 included in the tag. 3740 If generating a new ISO 2009 SWID tag, the software generating the 3741 tag MUST use a Tag Creator RegID that is associated with the 3742 generating software unless this is impossible, in which case it MUST 3743 use "unknown", which indicates the Tag Creator is unknown. (This 3744 conforms to conventions for an unknown Tag Creator in the ISO 2009 3745 SWID specification.) Do not use a RegID associated with any other 3746 party. In particular, it is incorrect to use a Tag Creator RegID 3747 associated with the software being described by the tag, the 3748 enterprise that is using the software, or any other entity except 3749 that of the party that built the tool that is generating the SWID 3750 tag. This reflects the requirement that the Tag Creator RegID 3751 identify the party that created the tag. 3753 6.2.2. Guidance on Creation of Software Identifiers from ISO 2009 SWID 3754 Tags 3756 A Software Identifier generated from an ISO 2009 SWID tag is 3757 expressed as a concatenation of the value of the Tag Creator RegID 3758 field and the Unique ID field. Specifically, it MUST be of the form: 3759 TAG_CREATOR_REGID "_" "_" UNIQUE_ID. Specifically, the Software 3760 Identifier consists of, the Tag Creator RegID and the Unique ID from 3761 the tag connected with a double underscore (_), without any other 3762 connecting character or whitespace. 3764 7. Security Considerations 3766 This section discusses some of the security threats facing Posture 3767 Collectors and Posture Validators that implement the SWIMA protocol. 3768 This section primarily notes potential issues for implementers to 3769 consider, although it does contain a handful of normative 3770 requirements to address certain security issues. The issues 3771 identified below focus on capabilities specific to this document. 3772 Implementers are advised to consult other relevant NEA 3773 specifications, particularly [RFC5209] (the NEA Architecture) and 3774 [RFC5792] (PA-TNC), for security issues that are applicable to such 3775 components in general. 3777 7.1. Evidentiary Value of Software Inventory Evidence Records 3779 The degree to which an endpoint's Software Inventory Evidence 3780 Collection accurately reflects the endpoint's actual software load 3781 and any changes made to this software load is dependent on the 3782 accuracy of the tools used to populate and manage the software 3783 inventory evidence records in this collection. While the SWIMA-PC is 3784 required to detect changes to an endpoint's Software Inventory 3785 Evidence Collection in near real-time, some tools might not be 3786 designed to update records in the Software Inventory Evidence 3787 Collection in real time. This can result in a collection that is 3788 out-of-sync with actual system state. Moreover, tools might 3789 inaccurately characterize software, or fail to properly record its 3790 removal. Finally, it is likely that there will be software on the 3791 endpoint that is not tracked by any source and thus is not reflected 3792 in the Software Inventory Evidence Collection. Tools that implement 3793 SWIMA ought to be aware of these potential issues and minimize them, 3794 but completely eliminating such issues is likely impossible. Users 3795 of collected software inventory evidence records need to understand 3796 that the information provided by the SWIMA capability cannot be 3797 treated as completely accurate. Nonetheless, having endpoints report 3798 this information can still provide useful insights into the state of 3799 the endpoint's software load, and can alert administrators and policy 3800 tools of situations that require remediation. 3802 7.2. Sensitivity of Collected Records 3804 Collected software records can be sensitive in nature. This can 3805 include both security sensitivities and privacy sensitivities. 3806 Privacy sensitivities are discussed more in Section 8. With regard 3807 to security, inventory records represent a wealth of information 3808 about the endpoint in question and, for an adversary who does not 3809 already have access to the endpoint, a collection of the endpoint's 3810 inventory records might provide many details that are useful for 3811 mounting an attack. A list of the inventory records associated with 3812 an endpoint reveals a list of software installed on the endpoint. 3813 This list can be very detailed, noting specific versions and even 3814 patch levels, which an adversary can use to identify vulnerable 3815 software and design efficacious attacks. 3817 In addition, other information might also be gleaned from a 3818 collection of software inventory records: 3820 o An inventory record might include information about where the 3821 product was installed on a given endpoint. This can reveal 3822 details about the file organization of that endpoint that an 3823 attacker can utilize. 3825 o An inventory record might include information about how the 3826 software was provided to the endpoint, who in an organization 3827 signs off on the package release, and who packaged the product for 3828 installation. This information might be used as a starting point 3829 for the development of supply chain attacks. 3831 o Events affecting inventory records are reported with timestamps 3832 indicating when each given event occurred. This can give the 3833 attacker an indication of how quickly an organization distributes 3834 patches and updates, helping the attacker determine how long an 3835 attack window might remain open. 3837 Any consolidated software inventory is a potential risk, because such 3838 an inventory can provide an adversary an insight into the 3839 enterprise's configuration and management process. It is recommended 3840 that a centralized software inventory record collection be protected 3841 against unauthorized access. Mechanisms to accomplish this can 3842 include encrypting the data at rest, ensuring that access to the data 3843 is limited only to authorized individuals and processes, and other 3844 basic security precautions. 3846 7.3. Integrity of Endpoint Records 3848 SWIMA-PCs maintain records of detected changes to the endpoint's 3849 Software Inventory Evidence Collection. These records are used to 3850 respond to a SWIMA-PV's request for change events. The SWIMA-PV 3851 might use a list of reported events to update its understanding of 3852 the endpoint's Software Inventory Evidence Collection without needing 3853 to receive a full inventory report from the SWIMA-PC. For this 3854 reason, preserving the integrity of the SWIMA-PC's record of events 3855 is extremely important. If an attacker modifies the SWIMA-PC's 3856 record of changes to the endpoint's Software Inventory Evidence 3857 Collection, this might cause the SWIMA-PV's understanding of the 3858 endpoint's Software Inventory Evidence Collection to differ from its 3859 actual state. Results might include leading the SWIMA-PV to believe 3860 that absent software was present, that present software was absent, 3861 that patches have been installed even if this is not the case, or to 3862 be unaware of other changes to Software Inventory Evidence Records. 3863 As such, the SWIMA-PC MUST take steps to protect the integrity of its 3864 event records. 3866 In addition, records of established SWIMA-PV subscriptions also 3867 require protection against manipulation or corruption. If an 3868 attacker is able to modify or delete records of an established 3869 subscription by a SWIMA-PV, the SWIMA-PC might fail to correctly 3870 fulfill this subscription. The SWIMA-PV would not be aware that its 3871 subscription was not being correctly fulfilled unless it received 3872 additional information that indicated a discrepancy. For example, 3873 the SWIMA-PV might collect a full inventory and realize from this 3874 that certain events had not been correctly reported in accordance 3875 with an established subscription. For this reason, the SWIMA-PC MUST 3876 protect the integrity of subscription records. 3878 7.4. SWIMA-PC Access Permissions 3880 A SWIMA-PC requires sufficient permissions to collect Software 3881 Inventory Evidence Records from all of its supported sources, as well 3882 as sufficient permissions to interact with the endpoint's Posture 3883 Broker Client. With regard to the former, this might require 3884 permissions to read the contents of directories throughout the file 3885 system. Depending on the operating environment and other activities 3886 undertaken by a SWIMA-PC (or software that incorporates a SWIMA-PC as 3887 one of its capabilities) additional permissions might be required by 3888 the SWIMA-PC software. The SWIMA-PC SHOULD NOT be granted 3889 permissions beyond what it needs in order to fulfill its duties. 3891 7.5. Sanitization of Record Fields 3893 Not all sources of software inventory evidence are necessarily 3894 tightly controlled. For example, consider a source that gathers 3895 .swid files from the endpoint's file system. Any party could create 3896 a new .swid file that could be collected and turned into a Software 3897 Inventory Evidence Record. As a result, it is important that the 3898 contents of source information not be automatically trusted. In 3899 particular, tools that read source information and the Software 3900 Inventory Evidence Records derived therefrom, including SWIMA-PCs, 3901 need to be careful to sanitize input to prevent buffer overflow 3902 attacks, encoding attacks, and other weaknesses that might be 3903 exploited by an adversary who can control the contents of a record. 3905 7.6. PA-TNC Security Threats 3907 In addition to the aforementioned considerations the SWIMA protocol 3908 is subject to the same security threats as other PA-TNC transactions, 3909 as noted in Section 5.2 of PA-TNC [RFC5792]. These include, but are 3910 not limited to, attribute theft, message fabrication, attribute 3911 modification, attribute replay, attribute insertion, and denial of 3912 service. Implementers are advised to consult the PA-TNC 3913 specification to better understand these security issues. 3915 8. Privacy Considerations 3917 As noted in Section 7.2, if an adversary can gain an understanding of 3918 the software installed on an endpoint, they can utilize this to 3919 launch attacks and maintain footholds on this endpoint. For this 3920 reason, the NEA Server needs to ensure adequate safeguards are in 3921 place to prevent exposure of collected inventory records. For 3922 similar reasons, it is advisable that an endpoint only send records 3923 to a NEA Server that is authorized to receive this information and 3924 that can be trusted to safeguard this information after collection. 3926 In addition, software inventory information can lead to insights 3927 about the endpoint's primary user if that user is able to install 3928 software. (Note that users might be "able" to install their own 3929 software even if they are not "allowed" to do so.) This is 3930 especially true on endpoints that support "apps", as individual apps 3931 can be closely tied to specific groups or activities. This could 3932 conceivably allow inferences about things such as a user's hobbies, 3933 the banks and other financial institutions that they use, and 3934 information about the user's race, sex, or sexual orientation. 3936 Organizations that collect software inventory information from 3937 endpoints ought to make sure the endpoints' users are aware of this 3938 collection. In addition, organizations should be aware that a 3939 software inventory associated with an individual, such as the 3940 inventory of the individual's primary endpoint, could expose 3941 sensitive personal information. For this reason, privacy safeguards 3942 are necessary for collected inventory information. Such safeguards 3943 would require not only protection of the inventory's confidentiality, 3944 but also appropriate access controls so that only those trained in 3945 relevant privacy requirements are able to view the data. 3947 9. Relationship to Other Specifications 3949 This specification is expected to participate in a standard NEA 3950 architecture. As such, it is expected to be used in conjunction with 3951 the other protocols used in a NEA exchange. In particular, SWIMA 3952 Attributes are conveyed over PB-TNC [RFC5793], which is in turn 3953 conveyed over some variant of PT (either PT-TLS [RFC6876] or PT-EAP 3954 [RFC7171]). These protocols have an especially important role, as 3955 they are responsible for ensuring that attributes defined under this 3956 specification are delivered reliably, securely, and to the 3957 appropriate party. 3959 It is important to note that the Product Information, Numeric 3960 Version, and String Version attributes defined in the PA-TNC 3961 specification [RFC5792] are also meant to convey information about 3962 installed applications and the versions thereof. As such, there is 3963 some conceptual overlap between those attributes and the intent of 3964 this specification. However, PA-TNC was designed to respond to very 3965 specific queries about specific classes of products, while the SWIMA 3966 specification is able to convey a broader query, resulting in a more 3967 comprehensive set of evidence regarding an endpoint's installed 3968 software. As such, this specification provides important 3969 capabilities not present in the PA-TNC specification. 3971 The NEA architecture is intended to support a broad range of 3972 activities and, as such, might be employed by other specifications. 3973 For example, requirement T-001 in the SACM Requirements document 3974 [RFC8248] notes that NEA can support data collection from endpoints 3975 within the broader SACM architecture. (Other parts of the NEA 3976 architecture, which SWIMA uses, meet the other SACM data transport 3977 requirements.) In the SACM architecture, a SWIMA-PV corresponds to a 3978 "SACM Collector" and a SWIMA-PC corresponds to a "SACM Internal 3979 Collector". In the SACM architecture, the SWIMA specification can 3980 support activities relating to software inventory collection. 3981 Specifically, SWIMA supports the SACM "Endpoint Posture Attribute 3982 Value Collection" use case (section 2.1.3 in [RFC7632]) by describing 3983 a collection mechanism that enables event driven, scheduled, and ad- 3984 hoc data collection of software inventory information. SWIMA's 3985 flexibility with regard to the format of inventory data records means 3986 that it is compatible with virtually any data format that implements 3987 SACM's "Define, Publish, Query, and Retrieve Security Automation 3988 Data" (section 2.1.1 in [RFC7632]). This is just one example of how 3989 SWIMA can support broader security solution standards. Note that, 3990 while SWIMA can support these SACM use cases, SWIMA has no 3991 dependencies upon the SACM architecture or any other context in which 3992 NEA might reasonably be applied. 3994 10. IANA Considerations 3996 This section extends multiple existing IANA registries. 3997 Specifically, it extends the PA-TNC Attribute Types and PA-TNC Error 3998 Codes defined in the PA-TNC specification [RFC5792] and the PA- 3999 Subtypes registry defined in the PB-TNC specification [RFC5793] and 4000 extended in PA-TNC. This specification only adds values to these 4001 registries and does not alter how these registries work or are 4002 maintained. Consult the appropriate specifications for details on 4003 the operations and maintenance of these registries. 4005 10.1. PA Subtypes 4007 The following is an extension to the PA Subtype registry [1] defined 4008 in section 7.2 of the PA-TNC specification [RFC5792]. 4010 +-----+---------+------------------+------------------------+ 4011 | PEN | Integer | Name | Defining Specification | 4012 +-----+---------+------------------+------------------------+ 4013 | 0 | 9 | SWIMA Attributes | [RFC-to-be] | 4014 +-----+---------+------------------+------------------------+ 4016 10.2. Registry for PA-TNC Attribute Types 4018 Section 5.4 of this specification defines several new PA-TNC 4019 attributes. The following values are added to the registry for PA- 4020 TNC Attribute Types defined in the PA-TNC specification. Note that 4021 Table 1 in Section 5.4 lists these attributes but uses a hexadecimal 4022 value to identify their associated integer. The integer values given 4023 in that table are identical to those provided here. Note also that 4024 Table 1 includes an entry for PA-TNC Error attributes, but the IANA 4025 information associated with that attribute is already defined in the 4026 PA-TNC specification and is not reproduced here. 4028 +-----+---------+----------------------------+----------------------+ 4029 | PEN | Integer | Name | Defining | 4030 | | | | Specification | 4031 +-----+---------+----------------------------+----------------------+ 4032 | 0 | 13 | SWIMA Request | [RFC-to-be] | 4033 | | | | | 4034 | 0 | 14 | Software Identifier | [RFC-to-be] | 4035 | | | Inventory | | 4036 | | | | | 4037 | 0 | 15 | Software Identifier Events | [RFC-to-be] | 4038 | | | | | 4039 | 0 | 16 | Software Inventory | [RFC-to-be] | 4040 | | | | | 4041 | 0 | 17 | Software Events | [RFC-to-be] | 4042 | | | | | 4043 | 0 | 18 | Subscription Status | [RFC-to-be] | 4044 | | | Request | | 4045 | | | | | 4046 | 0 | 19 | Subscription Status | [RFC-to-be] | 4047 | | | Response | | 4048 | | | | | 4049 | 0 | 20 | Source Metadata Request | [RFC-to-be] | 4050 | | | | | 4051 | 0 | 21 | Source Metadata Response | [RFC-to-be] | 4052 +-----+---------+----------------------------+----------------------+ 4054 10.3. Registry for PA-TNC Error Codes 4056 Section 5.16 of this specification defines several new PA-TNC Error 4057 Codes. The following values are added to the registry for PA-TNC 4058 Error Codes defined in the PA-TNC specification. Note that Table 8 4059 in Section 5.16 lists these codes but uses a hexadecimal value to 4060 identify their associated integer. The integer values given in that 4061 table are identical to those provided here. 4063 +----+--------+-------------------------------------+---------------+ 4064 | PE | Intege | Name | Defining | 4065 | N | r | | Specification | 4066 +----+--------+-------------------------------------+---------------+ 4067 | 0 | 4 | SWIMA_ERROR | [RFC-to-be] | 4068 | | | | | 4069 | 0 | 5 | SWIMA_SUBSCRIPTION_DENIED_ERROR | [RFC-to-be] | 4070 | | | | | 4071 | 0 | 6 | SWIMA_RESPONSE_TOO_LARGE_ERROR | [RFC-to-be] | 4072 | | | | | 4073 | 0 | 7 | SWIMA_SUBSCRIPTION_FULFILLMENT_ERRO | [RFC-to-be] | 4074 | | | R | | 4075 | | | | | 4076 | 0 | 8 | SWIMA_SUBSCRIPTION_ID_REUSE_ERROR | [RFC-to-be] | 4077 +----+--------+-------------------------------------+---------------+ 4079 10.4. Registry for Software Data Models 4081 The name for this registry is "Software Data Model Types". Each 4082 entry in this registry should include a human readable name, an SMI 4083 Private Enterprise Number, a decimal integer value between 1 and 4084 2^8-1 (inclusive), and a reference to the specification where the use 4085 of this data model is defined. This specification needs to provide 4086 both a description of the format used by the data model and the 4087 procedures by which Software Identifiers are derived from a record 4088 expressed using this data model. Note that a specification that just 4089 defines the data model structure and its use is generally not 4090 sufficient as it would likely lack the procedures for constructing a 4091 Software Identifier. This is why the table below references the 4092 current specification for ISO SWID tags, rather than using the actual 4093 ISO SWID tag specification. 4095 The following entries for this registry are defined in this document. 4096 They are the initial entries in the registry for Software Data Model 4097 Types. Additional entries to this registry are added by Expert 4098 Review with Specification Required, following the guidelines in 4099 [RFC8126]. 4101 +-----+---------+-----------------------------+---------------------+ 4102 | PEN | Integer | Name | Defining | 4103 | | | | Specification | 4104 +-----+---------+-----------------------------+---------------------+ 4105 | 0 | 0 | ISO 2015 SWID Tags using | [RFC-to-be] | 4106 | | | XML | | 4107 | | | | | 4108 | 0 | 1 | ISO 2009 SWID Tags using | [RFC-to-be] | 4109 | | | XML | | 4110 | | | | | 4111 | 0 | 192-255 | Reserved for local | N/A | 4112 | | | enterprise use | | 4113 +-----+---------+-----------------------------+---------------------+ 4115 11. References 4117 11.1. Normative References 4119 [NIST8060] 4120 Waltermire, D., Cheikes, B., Feldman, L., and G. Witte, 4121 "Guidelines for the Creation of Interoperable Software 4122 Identification (SWID) Tags", April 2016. 4124 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 4125 Requirement Levels", BCP 14, RFC 2119, 4126 DOI 10.17487/RFC2119, March 1997, 4127 . 4129 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: 4130 Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, 4131 . 4133 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 4134 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 4135 2003, . 4137 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 4138 Resource Identifier (URI): Generic Syntax", STD 66, 4139 RFC 3986, DOI 10.17487/RFC3986, January 2005, 4140 . 4142 [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network 4143 Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008, 4144 . 4146 [RFC5792] Sangster, P. and K. Narayan, "PA-TNC: A Posture Attribute 4147 (PA) Protocol Compatible with Trusted Network Connect 4148 (TNC)", RFC 5792, DOI 10.17487/RFC5792, March 2010, 4149 . 4151 [RFC8089] Kerwin, M., "The "file" URI Scheme", RFC 8089, 4152 DOI 10.17487/RFC8089, February 2017, 4153 . 4155 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 4156 Writing an IANA Considerations Section in RFCs", BCP 26, 4157 RFC 8126, DOI 10.17487/RFC8126, June 2017, 4158 . 4160 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 4161 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 4162 May 2017, . 4164 [SWID09] The International Organization for Standardization/ 4165 International Electrotechnical Commission, "Information 4166 Technology - Software Asset Management - Part 2: Software 4167 Identification Tag, ISO/IEC 19770-2", November 2009. 4169 [SWID15] The International Organization for Standardization/ 4170 International Electrotechnical Commission, "Information 4171 Technology - Software Asset Management - Part 2: Software 4172 Identification Tag, ISO/IEC 19770-2", October 2015. 4174 11.2. Informative References 4176 [RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J. 4177 Tardo, "Network Endpoint Assessment (NEA): Overview and 4178 Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008, 4179 . 4181 [RFC5793] Sahita, R., Hanna, S., Hurst, R., and K. Narayan, "PB-TNC: 4182 A Posture Broker (PB) Protocol Compatible with Trusted 4183 Network Connect (TNC)", RFC 5793, DOI 10.17487/RFC5793, 4184 March 2010, . 4186 [RFC6876] Sangster, P., Cam-Winget, N., and J. Salowey, "A Posture 4187 Transport Protocol over TLS (PT-TLS)", RFC 6876, 4188 DOI 10.17487/RFC6876, February 2013, 4189 . 4191 [RFC7171] Cam-Winget, N. and P. Sangster, "PT-EAP: Posture Transport 4192 (PT) Protocol for Extensible Authentication Protocol (EAP) 4193 Tunnel Methods", RFC 7171, DOI 10.17487/RFC7171, May 2014, 4194 . 4196 [RFC7632] Waltermire, D. and D. Harrington, "Endpoint Security 4197 Posture Assessment: Enterprise Use Cases", RFC 7632, 4198 DOI 10.17487/RFC7632, September 2015, 4199 . 4201 [RFC8248] Cam-Winget, N. and L. Lorenzin, "Security Automation and 4202 Continuous Monitoring (SACM) Requirements", RFC 8248, 4203 DOI 10.17487/RFC8248, September 2017, 4204 . 4206 11.3. URIs 4208 [1] https://www.iana.org/assignments/pb-tnc-parameters/pb-tnc- 4209 parameters.xhtml#pb-tnc-parameters-2 4211 Authors' Addresses 4213 Charles Schmidt 4214 The MITRE Corporation 4215 202 Burlington Road 4216 Bedford, MA 01730 4217 USA 4219 Email: cmschmidt@mitre.org 4221 Daniel Haynes 4222 The MITRE Corporation 4223 202 Burlington Road 4224 Bedford, MA 01730 4225 USA 4227 Email: dhaynes@mitre.org 4229 Chris Coffin 4230 The MITRE Corporation 4231 202 Burlington Road 4232 Bedford, MA 01730 4233 USA 4235 Email: ccoffin@mitre.org 4236 David Waltermire 4237 National Institute of Standards and Technology 4238 100 Bureau Drive 4239 Gaithersburg, Maryland 4240 USA 4242 Email: david.waltermire@nist.gov 4244 Jessica Fitzgerald-McKay 4245 United States National Security Agency 4246 9800 Savage Road 4247 Ft. Meade, Maryland 4248 USA 4250 Email: jmfitz2@radium.ncsc.mil