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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SACM N. Cam-Winget 3 Internet-Draft Cisco Systems 4 Intended status: Informational L. Lorenzin 5 Expires: December 29, 2017 Pulse Secure 6 June 27, 2017 8 Security Automation and Continuous Monitoring (SACM) Requirements 9 draft-ietf-sacm-requirements-17 11 Abstract 13 This document defines the scope and set of requirements for the 14 Secure Automation and Continuous Monitoring (SACM) architecture, data 15 model and transfer protocols. The requirements and scope are based 16 on the agreed upon use cases ([RFC7632]). 18 Status of This Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at http://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on December 29, 2017. 35 Copyright Notice 37 Copyright (c) 2017 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 53 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 54 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3 55 2.1. Requirements for SACM . . . . . . . . . . . . . . . . . . 4 56 2.2. Requirements for the Architecture . . . . . . . . . . . . 7 57 2.3. Requirements for the Information Model . . . . . . . . . 9 58 2.4. Requirements for the Data Model . . . . . . . . . . . . . 10 59 2.5. Requirements for Data Model Operations . . . . . . . . . 12 60 2.6. Requirements for SACM Transfer Protocols . . . . . . . . 14 61 3. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 62 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 63 5. Security Considerations . . . . . . . . . . . . . . . . . . . 15 64 5.1. Trust between Provider and Requestor . . . . . . . . . . 16 65 5.2. Privacy Considerations . . . . . . . . . . . . . . . . . 17 66 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 67 6.1. Normative References . . . . . . . . . . . . . . . . . . 18 68 6.2. Informative References . . . . . . . . . . . . . . . . . 18 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 71 1. Introduction 73 Today's environment of rapidly-evolving security threats highlights 74 the need to automate the sharing of security information (such as 75 posture information) while protecting user information and the 76 systems that store, process, and transmit this information. Security 77 threats can be detected in a number of ways. The Secure Automation 78 and Continuous Monitoring (SACM) charter focuses on how to collect 79 and share this information based on use cases that involve posture 80 assessment of endpoints. 82 Scalable and sustainable collection, expression, and evaluation of 83 endpoint information is foundational to SACM's objectives. To secure 84 and defend a network, one must reliably determine what devices are on 85 the network, how those devices are configured from a hardware 86 perspective, what software products are installed on those devices, 87 and how those products are configured. We need to be able to 88 determine, share, and use this information in a secure, timely, 89 consistent, and automated manner to perform endpoint posture 90 assessments. 92 This document focuses on describing the requirements for facilitating 93 the exchange of posture assessment information in the enterprise, in 94 particular, for the use cases as exemplified in [RFC7632]. As 95 proposals are evaluated for SACM standardization, their drafts are 96 expected to include a section that describe how they address each of 97 the enumerated requirements. 99 Also, this document uses terminology defined in 100 [I-D.ietf-sacm-terminology]. 102 1.1. Requirements Language 104 Use of each capitalized word within a sentence or phrase carries the 105 following meaning during the SACM WG's protocol selection process: 107 MUST - indicates an absolute requirement 109 MUST NOT - indicates something absolutely prohibited 111 SHOULD - indicates a strong recommendation of a desired result 113 SHOULD NOT - indicates a strong recommendation against a result 115 MAY - indicates a willingness to allow an optional outcome 117 When the words appear in lower case, their natural language meaning 118 is used. 120 2. Requirements 122 This document defines requirements based on the SACM use cases 123 described in [RFC7632]. This section describes the requirements used 124 by SACM to assess and compare candidate data models, interfaces, and 125 protocols. These requirements express characteristics or features 126 that a candidate protocol, information model, or data model must be 127 capable of offering to ensure security and interoperability. 129 Multiple data models, protocols, and transfers may be employed in a 130 SACM environment. A SACM transfer protocol is one that runs on top 131 of transport layer protocols such as TCP/IP or internet layer 132 protocols such as HTTP, carries operations (requests / responses), 133 and moves data. 135 SACM will define an architecture and information model focused on 136 addressing the needs for determining, sharing, and using posture 137 information via Posture Information Providers and Posture Information 138 Consumers securely. With the information model defining assets and 139 attributes to facilitate the guidance, collection, and assessment of 140 posture, tasks that should be considered include: 142 1. Asset Classification: Map the target endpoint and/or the assets 143 on the target endpoints to asset classes. This enables 144 identification of the attributes needed to exchange information 145 pertaining to the target endpoint. 147 2. Attribute Definition: Define the attributes desired to be 148 collected from each target endpoint. For instance, organizations 149 will want to know what software is installed and its critical 150 security attributes such as patch level. 152 3. Policy Definition: This is where an organization can express its 153 policy for acceptable or problematic values of an endpoint 154 attribute. The expected values of an endpoint attribute are 155 determined for later comparison against the actual endpoint 156 attribute values during the evaluation process. Expected values 157 may include both those values which are good as well as those 158 values which represent problems, such as vulnerabilities. The 159 organization can also specify the endpoint attributes that are to 160 be present for a given target endpoint. 162 4. Information Collection: Collect information (attribute values) 163 from the target endpoint to populate the endpoint data. 165 5. Endpoint Assessment: Evaluate the actual values of the endpoint 166 attributes against those expressed in the policy. (An evaluation 167 result may become additional endpoint data). 169 6. Result Reporting: Report the results of the evaluation for use by 170 other components. Examples of use of a report would be 171 additional evaluation, network enforcement, vulnerability 172 detection, and license management. 174 2.1. Requirements for SACM 176 Many deployment scenarios can be instantiated to address the above 177 tasks and use cases defined in [RFC7632]. To ensure 178 interoperability, scalability, and flexibility in any of these 179 deployments, the following requirements are defined for proposed SACM 180 standards: 182 G-001 Solution Extensibility: The information model, data models, 183 protocols, and transfers defined by SACM MUST be designed to allow 184 support for future (SACM) extensions. SACM MUST allow 185 implementations to use their own extensions; either proprietary data 186 models, protocols or extensions to SACM data models or protocols 187 could be used though they are not considered to be SACM compliant. 189 1. The information model and programmatic interfaces (see G-012 for 190 one example) MUST support the ability to add new operations 191 while maintaining backwards compatibility. SACM-defined 192 transfer protocols MUST have extensibility to allow them to 193 transfer operations that are defined in the future. 195 2. The query language MUST allow for general inquiries, as well as 196 expression of specific attributes or relationships between 197 attributes; the retrieval of specific information based on an 198 event, or on a continuous basis; and the ability to retrieve 199 specific pieces of information, specific types or classes of 200 information, or the entirety of available information. 202 3. The information model MUST accommodate the interoperable 203 addition of new data types and/or schemas. 205 G-002 Interoperability: The data models, protocols, and transpors 206 MUST be specified with enough details to ensure interoperability. 208 G-003 Scalability: SACM needs to support a broad set of deployment 209 scenarios. The data models, protocols, and transports has to be 210 scalable unless they are specifically defined to apply to a special- 211 purpose scenario, such as constrained devices. A SACM transfer 212 protocol standard SHOULD include a section on scalability 213 considerations that addresses the number of endpoints and amount of 214 information to which it can reasonably be expected to scale. 215 Scalability must be addressed to support: 217 * Large message: It is possible that the size of posture assessment 218 information can vary from a single assessment that is small in 219 size to a very large message or a very large set of assessments 220 (up to multiple gigabytes in size). 222 * Large number of messages per second: A deployment may involve 223 many rapid or simultaneous events that require processing, 224 generating many messages per second. 226 * Large number of providers and consumers: A deployment may consist 227 of a very large number of endpoints requesting and/or producing 228 posture assessment information. 230 * Large number of target endpoints: A deployment may be managing 231 information of a very large number of target endpoints. 233 G-004 Versatility: The data model, protocols, and transports MUST be 234 suitably specified to enable implementations to fit into different 235 deployment models and scenarios, including considerations for 236 implementations of data models and transports operating in 237 constrained environments. Separate solutions may be necessary to 238 meet the needs of specific deployment models and scenarios. 240 G-005 Information Extensibility: Non-standard (implementation- 241 specific) attributes MUST be supported. A method SHOULD be defined 242 for preventing collisions from occurring in the naming of all 243 attributes independent of their source. For interoperability and 244 scope boundary, the information model MUST define the mandatory set 245 of attributes. 247 G-006 Data Protection: To protect the information being shared, SACM 248 components MUST protect the integrity and confidentiality of data in 249 transit (while information is being transferred between providers 250 and consumers, and through middle boxes and/or repositories) and 251 data at rest (for information stored on repositories and on 252 providers / consumers). Mechanisms for this protection are 253 unspecified but should include industry best practices. These 254 mechanisms are required to be available (i.e. all data-handling 255 components must support them), but are not required to be used in 256 all cases. 258 G-007 Data Partitioning: A method for partitioning data MUST be 259 supported to accommodate considerations such as geographic, 260 regulatory, operational requirements, overlay boundaries, and 261 federation (where the data may be collected in multiple locations 262 and either centralized or kept in the local region). Where 263 replication of data is supported, it is required that methods exist 264 to prevent update loops. 266 G-008 Versioning and Backward Compatibility: Announcement and 267 negotiation of versions, inclusive of existing capabilities (such as 268 transfer protocols, data models, specific attributes within data 269 models, standard attribute expression sets, etc.) MUST be 270 supported. Negotiation for both versioning and capabilities is 271 needed to accommodate future growth and ecosystems with mixed 272 capabilities. 274 G-009 Information Discovery: There MUST be mechanisms for components 275 to discover what information is available across the ecosystem (i.e. 276 a method for cataloging data available in the ecosystem and 277 advertising it to consumers), where to go to get a specific piece of 278 that information (i.e. which provider has the information), and what 279 schemas are in use for organizing the information. For example, 280 providing a method by which a node can locate the advertised 281 information so that consumers are not required to have a priori 282 knowledge to find available information. 284 G-010 Target Endpoint Discovery: SACM MUST define the means by which 285 target endpoints may be discovered. Use Case 2.1.2 describes the 286 need to discover endpoints and their composition. 288 G-011 Push and Pull Access: Three methods of data access MUST be 289 supported: a Pull model, a solicited Push model, and an unsolicited 290 Push models. All of the methods of data access MUST support the 291 ability for the initiator to filter the set of posture assessment 292 information to be delivered. Additionally, the provider of the 293 information MUST be able to filter the set of posture assessment 294 information based on the permissions of the recipient. This 295 requirement is driven by use cases 2.1.3, 2.1.4 and 2.1.5. 297 G-012 SACM Component Interface: The interfaces by which SACM 298 components communicate to share endpoint posture information MUST be 299 well defined. That is, the interface defines the data model, SACM 300 transfer protocols, and network transfer protocols to enable SACM 301 components to communicate. 303 G-013 Endpoint Location and Network Topology: The SACM architecture 304 and interfaces MUST allow for the target endpoint (network) location 305 and network topology to be modeled and understood. Where 306 appropriate, the data model and the interfaces SHOULD allow for 307 discovery of the target endpoint location or network topology or 308 both. 310 G-014 Target Endpoint Identity: The SACM architecture and interfaces 311 MUST support the ability of components to provide attributes that 312 can be used to compose an identity for a target endpoint. These 313 identities MAY be composed of attributes from one or more SACM 314 components. 316 G-015 Data Access Control: Methods of access control MUST be 317 supported to accommodate considerations such as geographic, 318 regulatory, operational and federations. Entities accessing or 319 publishing data MUST identify themselves and pass access policy. 321 2.2. Requirements for the Architecture 323 At the simplest abstraction, the SACM architecture MUST represent the 324 core components and interfaces needed to perform the production and 325 consumption of posture assessment information. Requirements relating 326 to SACM's architecture include: 328 ARCH-001 Scalability: The architectural components MUST account for 329 a range of deployments, from very small sets of endpoints to very 330 large deployments. 332 ARCH-002 Flexibility: The architectural components MUST account for 333 different deployment scenarios where the architectural components 334 may be implemented, deployed, or used within a single application, 335 service, or network, or may comprise a federated system. 337 ARCH-003 Separation of Data and Management Functions: SACM MUST 338 define both the configuration and management of the SACM data models 339 and protocols used to transfer and share posture assessment 340 information. 342 ARCH-004 Topology Flexibility: Both centralized and decentralized 343 (peer-to-peer) information exchange MUST be supported. Centralized 344 data exchange enables use of a common data format to bridge together 345 data exchange between diverse systems, and can leverage a virtual 346 data store that centralizes and offloads all data access, storage, 347 and maintenance to a dedicated resource. Decentralized data 348 exchange enables simplicity of sharing data between relatively 349 uniform systems, and between small numbers of systems, especially 350 within a single enterprise domain. The fact that a centralized or 351 decentralized deployment is used SHOULD be invisible to a consumer. 353 ARCH-005 Capability Negotiation: Announcement and negotiation of 354 functional capabilities (such as authentication protocols, 355 authorization schemes, data models, transfer protocols, etc.) MUST 356 be supported, enabling a SACM component to make inquiries about the 357 capabilities of other components in the SACM ecosystem. 359 ARCH-006 Role-based Authorization: The SACM architecture MUST be 360 capable of effecting role-based authorization. Distinction of 361 endpoints capable of and authorized to provide or consume 362 information is required to address appropriate access controls. 364 ARCH-007 Context-based Authorization: The SACM architecture MUST be 365 capable of effecting context-based authorization. Different 366 policies (e.g. business, regulatory, etc.) might specify what data 367 may be exposed to, or shared by, consumers based on one or more 368 attributes of the consumer. The policy might specify that consumers 369 are required to share specific information either back to the system 370 or to administrators. 372 ARCH-008 Time Synchronization: Actions or decisions based on time- 373 sensitive data (such as user logon/logoff, endpoint connection/ 374 disconnection, endpoint behavior events, etc.) are all predicated on 375 a synchronized understanding of time. The SACM architecture MUST 376 provide a mechanism for all components to synchronize time. A 377 mechanism for detecting and reporting time discrepancies SHOULD be 378 provided by the architecture and reflected in the information model. 380 2.3. Requirements for the Information Model 382 The SACM information model represents the abstracted representation 383 for Posture Assessment information to be communicated. SACM data 384 models must adhere to and comply with the SACM information model. 385 The requirements for the SACM information model include: 387 IM-001 Extensible Attribute Vocabulary: The information model MUST 388 define a minimum set of attributes for communicating Posture 389 Information, to ensure interoperability between data models. 390 (Individual data models may define attributes beyond the mandatory- 391 to-implement minimum set.) The attributes should be defined with a 392 clear mechanism for extensibility to enable data models to adhere to 393 SACM's required attributes as well as allow for their own 394 extensions. The attribute vocabulary should be defined with a clear 395 mechanism for extensibility to enable future versions of the 396 information model to be interoperably expanded with new attributes. 398 IM-002 Posture Data Publication: The information model MUST allow 399 for the data to be provided by a SACM component either solicited or 400 unsolicited. No aspect of the information model should be dependent 401 upon or assume a push or pull model of publication. 403 IM-003 Data Model Negotiation: SACM's information model MUST allow 404 support for different data models, data model versions, and 405 different versions of the operations on the data models and transfer 406 protocols. The SACM information model MUST include the ability to 407 discover and negotiate the use of a particular data model or any 408 data model. 410 IM-004 Data Model Identification: The information model MUST provide 411 a means to uniquely identify each data model. The identifier MUST 412 contain both an identifier of the data model and a version indicator 413 for the data model. The identifiers SHOULD be decomposable so that 414 a customer can query for any version of a specific data model and 415 compare returned values for older or newer than a desired version. 417 IM-005 Data Lifetime Management: The information model MUST provide 418 a means to allow data models to include data lifetime management. 419 The information model must identify attributes that can allow data 420 models to, at minimum, identify the data's origination time and 421 expected time of next update or data longevity (how long should the 422 data be assumed to still be valid). 424 IM-006 Singularity and Modularity: The SACM information model MUST 425 be singular (i.e. there is only one information model, not multiple 426 alternative information models from which to choose) and MAY be 427 modular (a conjunction of several sub-components) for ease of 428 maintenance and extension. For example, endpoint identification 429 could be an independent sub-component of the information model, to 430 simplify updating of endpoint identification attributes. 432 2.4. Requirements for the Data Model 434 The SACM information model represents an abstraction for "what" 435 information can be communicated and "how" it is to be represented and 436 shared. It is expected that as applications may produce posture 437 assessment information, they may share it using a specific data 438 model. Similarly, applications consuming or requesting posture 439 assessment information, may require it be based on a specific data 440 model. Thus, while there may exist different data models and 441 schemas, they should adhere to the SACM information model and meet 442 the requirements defined in this section. 444 The specific requirements for candidate data models include: 446 DM-001 Element Association: A SACM Information Model consists of a 447 set of SACM Information Model elements. A SACM Data Model MUST be 448 derived from the SACM Information Model. A SACM Data Model consists 449 of a set of SACM Data Model elements. In this derivation, a SACM 450 Data Model element MAY map to one or more SACM Information Model 451 elements. In addition, a SACM Data Model MAY include additional 452 Data Model elements that are not associated with any SACM 453 Information Model elements. 455 DM-002 Data Model Structure: The data model can be structured either 456 as one single module or separated into modules and sub-modules that 457 allow for references between them. The data model structure MAY 458 reflect structure in the information model, but does not need to. 459 For example, the data model might use one module to define 460 endpoints, and that module might reference other modules that 461 describe the various assets associated with the endpoint. 462 Constraints and interfaces might further be defined to resolve or 463 tolerate ambiguity in the references (e.g. same IP address used in 464 two separate networks). 466 DM-003 Search Flexibility: The search interfaces and actions MUST 467 include the ability to start a search anywhere within a data model 468 structure, and the ability to search based on patterns ("wildcard 469 searches") as well as specific data elements. 471 DM-004 Full vs. Partial Updates: The data model SHOULD include the 472 ability to allow providers of data to provide the data as a whole, 473 or when updates occur. For example, a consumer can request a full 474 update on initial engagement, then request to receive deltas 475 (updates containing only the changes since the last update) on an 476 ongoing basis as new data is generated. 478 DM-005 Loose Coupling: The data model SHOULD allow for a loose 479 coupling between the provider and the consumer, such that the 480 consumer can request information without being required to request 481 it from a specific provider, and a provider can publish information 482 without having a specific consumer targeted to receive it. 484 DM-006 Data Cardinality: The data model MUST describe their 485 constraints (e.g. cardinality). As posture information and the 486 tasks for collection, aggregation, or evaluation, could comprise one 487 or more attributes, interfaces and actions MUST allow and account 488 for such cardinality as well as whether the attributes are 489 conditional, optional, or mandatory. 491 DM-007 Data Model Negotiation: The interfaces and actions in the 492 data model MUST include capability negotiation to enable discovery 493 of supported and available data types and schemas. 495 DM-008 Data Origin: The data model MUST include the ability for 496 consumers to identify the data origin (provider that collected the 497 data). 499 DM-009 Origination Time: The data model SHOULD allow the provider to 500 include the information's origination time. 502 DM-010 Data Generation: The data model MUST allow the provider to 503 include attributes defining how the data was generated (e.g. self- 504 reported, reported by aggregator, scan result, etc.). 506 DM-011 Data Source: The data model MUST allow the provider to 507 include attributes identifying the data source (target endpoint from 508 which the data was collected) - e.g. hostname, domain (DNS) name or 509 application name. 511 DM-012 Data Updates: The data model SHOULD allow the provider to 512 include attributes defining whether the information provided is a 513 delta, partial, or full set of information. 515 DM-013 Multiple Collectors: The data model MUST support the 516 collection of attributes by a variety of collectors, including 517 internal collectors, external collectors with an authenticated 518 relationship with the endpoint, and external collectors based on 519 network and other observers. 521 DM-014 Attribute Extensibility: Use Cases in the whole of Section 2 522 describe the need for an attribute dictionary. With SACM's scope 523 focused on posture assessment, the data model attribute collection 524 and aggregation MUST have a well-understood set of attributes 525 inclusive of their meaning or usage intent. The data model MUST 526 include all attributes defined in the information model and MAY 527 include additional attributes beyond those found in the information 528 model. Additional attributes MUST be defined in accordance with the 529 extensibility framework provided in the information model (see IM- 530 001). 532 DM-015 Solicited vs. Unsolicited Updates: The data model MUST enable 533 a provider to publish data either solicited (in response to a 534 request from a consumer) or unsolicited (as new data is generated, 535 without a request required). For example, an external collector can 536 publish data in response to a request by a consumer for information 537 about an endpoint, or can publish data as it observes new 538 information about an endpoint, without any specific consumer request 539 triggering the publication; a compliance-server provider may publish 540 endpoint posture information in response to a request from a 541 consumer (solicited), or it may publish posture information driven 542 by a change in the posture of the endpoint (unsolicited). 544 DM-016 tTransfer Agnostic: The data model MUST be transfer agnostic, 545 to allow for the data operations to leverage the most appropriate 546 SACM transfer protocol. 548 2.5. Requirements for Data Model Operations 550 Posture information data adhering to a data model must also provide 551 interfaces that include operations for access and production of the 552 data. Operations requirements are distinct from transfer 553 requirements in that operations requirements are requirements on the 554 application performing requests and responses, whereas transfer 555 requirements are requirements on the transfer protocol carrying the 556 requests / responses. The specific requirements for such operations 557 include: 559 OP-001 Time Synchronization: Request and response operations MUST be 560 timestamped, and published information SHOULD capture time of 561 publication. Actions or decisions based on time-sensitive data 562 (such as user logon/logoff, endpoint connection/disconnection, 563 endpoint behavior events, etc.) are all predicated on a synchronized 564 understanding of time. A method for detecting and reporting time 565 discrepancies SHOULD be provided. 567 OP-002 Collection Abstraction: Collection is the act of a SACM 568 component gathering data from a target endpoint. The request for a 569 data item MUST include enough information to properly identify the 570 item to collect, but the request shall not be a command to directly 571 execute nor directly be applied as arguments to a command. The 572 purpose of this requirement is primarily to reduce the potential 573 attack vectors, but has the additional benefit of abstracting the 574 request for collection from the collection method, thereby allowing 575 more flexibility in how collection is implemented. 577 OP-003 Collection Composition: A collection request MAY be composed 578 of multiple collection requests (which yield collected values). The 579 desire for multiple values MUST be expressed as part of the 580 collection request, so that the aggregation can be resolved at the 581 point of collection without having to interact with the requestor. 582 This requirement should not be interpreted as preventing a collector 583 from providing attributes which were not part of the original 584 request. 586 OP-004 Attribute-based Query: A query operation is the act of 587 requesting data from a provider. Query operations SHOULD be based 588 on a set of attributes. Query operations MUST support both a query 589 for specific attributes and a query for all attributes. Use Case 590 2.1.2 describes the need for the data model to support a query 591 operation based on a set of attributes to facilitate collection of 592 information such as posture assessment, inventory (of endpoints or 593 endpoint components), and configuration checklist. 595 OP-005 Information-based Query with Filtering: The query operation 596 MUST support filtering. Use Case 2.1.3 describes the need for the 597 data model to support the means for the information to be collected 598 through a query mechanism. Furthermore, the query operation 599 requires filtering capabilities to allow for only a subset of 600 information to be retrieved. The query operation MAY be a 601 synchronous request or asynchronous request. 603 OP-006 Operation Scalability: The operation resulting from a query 604 operation MUST be able to handle the return and receipt of large 605 amounts of data. Use Cases 2.1.4 and 2.1.5 describe the need for 606 the data model to support scalability. For example, the query 607 operation may result in a very large set of attributes, as well as a 608 large set of targets. 610 OP-007 Data Abstraction: The data model MUST allow a SACM component 611 to communicate what data was used to construct the target endpoint's 612 identity, so other SACM components can determine whether they are 613 constructing an equivalent target endpoint (and its identity) and 614 whether they have confidence in that identity. SACM components 615 SHOULD have interfaces defined to transmit this data directly or to 616 refer to where the information can be retrieved. 618 OP-008 Provider Restriction: Request operations MUST include the 619 ability to restrict the data to be provided by a specific provider 620 or a provider with specific characteristics. Response operations 621 MUST include the ability to identify the provider that supplied the 622 response. For example, a SACM Consumer should be able to request 623 that all of the data come from a specific provider by identity (e.g. 624 Provider A) or from a Provider that is in a specific location (e.g. 625 in the Boston office). 627 2.6. Requirements for SACM Transfer Protocols 629 The term SACM transfer protocol is intended to be distinguished from 630 underlying transport and internet layer protocols such as TCP/IP or 631 operating at an equivalent level as the HTTP. The SACM transfer 632 protocol is focused on moving data and performing necessary access 633 control operations; it is agnostic to the data model operations. 635 The requirements for SACM transfer protocols include: 637 T-001 Multiple transfer Protocol Support: SACM transfer protocols 638 will vary depending on the deployment model that relies on different 639 transfer layer requirements, different device capabilities, and 640 system configurations dealing with connectivity. For example, where 641 posture attributes may be collected directly from an endpoint using 642 NEA's model [RFC5209], different transports may be defined to 643 collect them using PT-EAP [RFC7171] or PT-TLS [RFC6876] depending on 644 the deployment scenario. 646 T-002 Data Integrity: SACM transfer protocols MUST be able to ensure 647 data integrity for data in transit. 649 T-003 Data Confidentiality: SACM transfer protocols MUST be able to 650 support data confidentiality. SACM transfer protocols MUST ensure 651 data protection for data in transit (e.g. by encryption) to provide 652 confidentiality, integrity, and robustness against protocol-based 653 attacks. Note that while the transfer MUST be able to support data 654 confidentiality, implementations MAY provide a configuration option 655 that enables and disables confidentiality in deployments. 656 Protection for data at rest is not in scope for transfer protocols. 657 Data protection MAY be used for both privacy and non-privacy 658 scenarios. 660 T-004 Transfer Protection: SACM transfer protocols MUST be capable 661 of supporting mutual authentication and replay protection. 663 T-005 Transfer Reliability: SACM transfer protocols MUST provide 664 reliable delivery of data. This includes the ability to perform 665 fragmentation and reassembly, and to detect replays. The SACM 666 transfer may take advantage of reliability features in the network 667 transport; however, the network transport may be unreliable (e.g. 668 UDP), in which case the SACM transfer running over the unreliable 669 network transport is responsible for ensuring reliability (i.e. by 670 provisions such as confirmations and re-transmits). 672 T-006 Transfer Layer Requirements: Each SACM transfer protocol MUST 673 clearly specify the transport layer requirements it needs to operate 674 correctly. Examples of items that may need to be specified include 675 connectivity requirements, replay requirements, data link encryption 676 requirements, and/or channel binding requirements. These 677 requirements are needed in order for deployments to be done 678 correctly. 680 3. Acknowledgments 682 The authors would like to thank Barbara Fraser, Jim Bieda, and Adam 683 Montville for reviewing and contributing to this draft. In addition, 684 we recognize valuable comments and suggestions made by Jim Schaad and 685 Chris Inacio. 687 4. IANA Considerations 689 This memo includes no request to IANA. 691 5. Security Considerations 693 This document defines the requirements for SACM. As such, it is 694 expected that several data models, protocols, and transfer protocols 695 may be defined or reused from already existing standards. 697 To address security and privacy considerations, the data model, 698 protocols, and transports must consider authorization based on 699 consumer function and privileges, to only allow authorized consumers 700 and providers to access specific information being requested or 701 published. 703 To enable federation across multiple entities (such as across 704 organizational or geographic boundaries) authorization must also 705 extend to infrastructure elements themselves, such as central 706 controllers / brokers / data repositories. 708 In addition, authorization needs to extend to specific information or 709 resources available in the environment. In other words, 710 authorization is based on the subject (the information requestor), 711 the provider (the information responder), the object (the endpoint 712 the information is being requested on), and the attribute (what piece 713 of data is being requested). The method by which this authorization 714 is applied is unspecified. 716 SACM's charter focuses on the workflow orchestration and the sharing 717 of posture information for improving efficacy of security 718 applications such as compliance, configuration, assurance and other 719 threat and vulnerability reporting and remediation systems. While 720 the goal is to facilitate the flow of information securely, it is 721 important to note that participating endpoints may not be cooperative 722 or trustworthy. 724 5.1. Trust between Provider and Requestor 726 The information given from the provider to a requestor may come with 727 different levels of trustworthiness given the different potential 728 deployment scenarios and compromise either at the provider, the 729 requesting consumer, or devices that are involved in the transfer 730 between the provider and requestor. This section will describe the 731 different considerations that may reduce the level of trustworthiness 732 of the information provided. 734 In the information transfer flow, it is possible that some of the 735 devices may serve as proxies or brokers and as such, may be able to 736 observe the communications flowing between an information provider 737 and requestor. Without appropriate protections, it is possible for 738 these proxies and brokers to inject and affect man-in-the-middle 739 attacks. 741 It is common to, in general, distrust the network service provider, 742 unless the full hop by hop communications process flow is well 743 understood. As such, the posture information provider should protect 744 the posture information data it provides as well as the transfer it 745 uses. Similarly, while there may be providers whose goal is to 746 openly share its information, there may also be providers whose 747 policy is to grant access to certain posture information based on its 748 business or regulatory policy. In those situations, a provider may 749 require full authentication and authorization of the requestor (or 750 set of requestors) and share only the authorized information to the 751 authenticated and authorized requestors. 753 A requestor beyond distrusting the network service provider, must 754 also account that the information received from the provider may have 755 been communicated through an undetermined network communications 756 system. That is, the posture information may have traversed through 757 many devices before reaching the requestor. SACM specifications 758 should provide the means for verifying data origin and data integrity 759 and at minimum, provide endpoint authentication and transfer 760 integrity. 762 A requestor may require data freshness indications, both knowledge of 763 data origination as well as time of publication so that it can make 764 more informed decisions about the relevance of the data based on its 765 currency and/or age. 767 It is also important to note that endpoint assessment reports, 768 especially as they may be provided by the target endpoint may pose 769 untrustworthy information. The considerations for this are described 770 in Section 8 of [RFC5209]. 772 The trustworthiness of the posture information given by the provider 773 to one or many requestors is dependent on several considerations. 774 Some of these include the requestor requiring: 776 o Full disclosure of the network topology path to the provider(s). 778 o Direct (peer to peer) communication with the provider. 780 o Authentication and authorization of the provider. 782 o Either or both confidentiality and integrity at the transfer 783 layer. 785 o Either or both confidentiality and integrity at the data layer. 787 5.2. Privacy Considerations 789 SACM information may contain sensitive information about the target 790 endpoint as well as revealing identity information of the producer or 791 consumer of such information. Similarly, as part of the SACM 792 discovery mechanism, the advertised capabilities (and roles, e.g. 793 SACM components enabled) by the endpoint may be construed as private 794 information. 796 In addition to identity and SACM capabilities information disclosure, 797 the use of time stamps (or other attributes that can be used as 798 identifiers) could be further used to determine a target endpoint or 799 user's behavioral patterns. Such attributes may also be deemed 800 sensitive and may required further protection or obfuscation to meet 801 privacy concerns. That is, there may be applications as well as 802 business and regulatory practices that require that aspects of such 803 information be hidden from any parties that do not need to know it. 805 Data confidentiality can provide some level of privacy but may fall 806 short where unnecessary data is still transmitted. In those cases, 807 filtering requirements at the data model such as OP-005 must be 808 applied to ensure that such data is not disclosed. [RFC6973] 809 provides guidelines for which SACM protocols and information and data 810 models should follow. 812 6. References 814 6.1. Normative References 816 [RFC7632] Waltermire, D. and D. Harrington, "Endpoint Security 817 Posture Assessment: Enterprise Use Cases", RFC 7632, 818 DOI 10.17487/RFC7632, September 2015, 819 . 821 6.2. Informative References 823 [I-D.ietf-sacm-terminology] 824 Birkholz, H., Lu, J., Strassner, J., and N. Cam-Winget, 825 "Security Automation and Continuous Monitoring (SACM) 826 Terminology", draft-ietf-sacm-terminology-12 (work in 827 progress), March 2017. 829 [RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J. 830 Tardo, "Network Endpoint Assessment (NEA): Overview and 831 Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008, 832 . 834 [RFC6876] Sangster, P., Cam-Winget, N., and J. Salowey, "A Posture 835 Transport Protocol over TLS (PT-TLS)", RFC 6876, 836 DOI 10.17487/RFC6876, February 2013, 837 . 839 [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., 840 Morris, J., Hansen, M., and R. Smith, "Privacy 841 Considerations for Internet Protocols", RFC 6973, 842 DOI 10.17487/RFC6973, July 2013, 843 . 845 [RFC7171] Cam-Winget, N. and P. Sangster, "PT-EAP: Posture Transport 846 (PT) Protocol for Extensible Authentication Protocol (EAP) 847 Tunnel Methods", RFC 7171, DOI 10.17487/RFC7171, May 2014, 848 . 850 Authors' Addresses 851 Nancy Cam-Winget 852 Cisco Systems 853 3550 Cisco Way 854 San Jose, CA 95134 855 US 857 Email: ncamwing@cisco.com 859 Lisa Lorenzin 860 Pulse Secure 861 2700 Zanker Rd., Suite 200 862 San Jose, CA 95134 863 US 865 Email: llorenzin@pulsesecure.net