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2 SACM J. Salowey
3 Internet-Draft Tableau Software
4 Intended status: Standards Track L. Lorenzin
5 Expires: October 31, 2015 C. Kahn
6 Pulse Secure
7 S. Pope
8 S. Appala
9 A. Woland
10 N. Cam-Winget, Ed.
11 Cisco Systems
12 April 29, 2015
14 XMPP Protocol Extensions for Use in SACM Information Transport
15 draft-salowey-sacm-xmpp-grid-02
17 Abstract
19 This document defines a transport protocol for use with the Security
20 Automation and Continuous Monitoring (SACM) Architecture.
22 Status of This Memo
24 This Internet-Draft is submitted in full conformance with the
25 provisions of BCP 78 and BCP 79.
27 Internet-Drafts are working documents of the Internet Engineering
28 Task Force (IETF). Note that other groups may also distribute
29 working documents as Internet-Drafts. The list of current Internet-
30 Drafts is at http://datatracker.ietf.org/drafts/current/.
32 Internet-Drafts are draft documents valid for a maximum of six months
33 and may be updated, replaced, or obsoleted by other documents at any
34 time. It is inappropriate to use Internet-Drafts as reference
35 material or to cite them other than as "work in progress."
37 This Internet-Draft will expire on October 31, 2015.
39 Copyright Notice
41 Copyright (c) 2015 IETF Trust and the persons identified as the
42 document authors. All rights reserved.
44 This document is subject to BCP 78 and the IETF Trust's Legal
45 Provisions Relating to IETF Documents
46 (http://trustee.ietf.org/license-info) in effect on the date of
47 publication of this document. Please review these documents
48 carefully, as they describe your rights and restrictions with respect
49 to this document. Code Components extracted from this document must
50 include Simplified BSD License text as described in Section 4.e of
51 the Trust Legal Provisions and are provided without warranty as
52 described in the Simplified BSD License.
54 Table of Contents
56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
57 1.1. Glossary of Terms . . . . . . . . . . . . . . . . . . . . 3
58 1.2. What is XMPP-Grid? . . . . . . . . . . . . . . . . . . . 6
59 1.3. Overview of XMPP-Grid . . . . . . . . . . . . . . . . . . 6
60 1.4. Benefits of XMPP-Grid . . . . . . . . . . . . . . . . . . 9
61 1.5. Example Workflow . . . . . . . . . . . . . . . . . . . . 10
62 2. Applicability of XMPP-Grid to SACM Use Cases . . . . . . . . 12
63 2.1. Applicability of XMPP-Grid to SACM Usage Scenarios . . . 12
64 2.1.1. SACM Definition and Publication of Automatable
65 Configuration Checklists . . . . . . . . . . . . . . 12
66 2.1.2. SACM Automated Checklist Verification . . . . . . . . 13
67 2.1.3. SACM Detection of Posture Deviations . . . . . . . . 13
68 2.1.4. SACM Endpoint Information Analysis and Reporting . . 14
69 2.1.5. SACM Asynchronous Compliance/Vulnerability Assessment
70 at Ice Station Zebra . . . . . . . . . . . . . . . . 14
71 2.1.6. SACM Identification and Retrieval of Guidance . . . . 14
72 2.1.7. SACM Guidance Change Detection . . . . . . . . . . . 15
73 3. XMPP-Grid Architecture . . . . . . . . . . . . . . . . . . . 15
74 3.1. XMPP Overview . . . . . . . . . . . . . . . . . . . . . . 16
75 3.2. XMPP-Grid Protocol Extensions to XMPP . . . . . . . . . . 17
76 3.3. XMPP-Grid Controller Protocol Flow . . . . . . . . . . . 18
77 3.4. XMPP-Grid Node Connection Protocol Flow . . . . . . . . . 20
78 3.4.1. Authentication . . . . . . . . . . . . . . . . . . . 20
79 3.4.2. Registration . . . . . . . . . . . . . . . . . . . . 20
80 3.4.3. Authorization . . . . . . . . . . . . . . . . . . . . 23
81 3.5. XMPP-Grid Topics Protocol Flow . . . . . . . . . . . . . 26
82 3.5.1. Topic Versioning . . . . . . . . . . . . . . . . . . 27
83 3.5.2. Topic Discovery . . . . . . . . . . . . . . . . . . . 27
84 3.5.3. Subtopics and Message Filters . . . . . . . . . . . . 27
85 3.6. XMPP-Grid Protocol Details . . . . . . . . . . . . . . . 30
86 4. XMPP-Grid Compatibility with IF-MAP Information Model . . . . 36
87 4.1. MAP Server as XMPP-Grid Subscriber for Metadata
88 Aggregation . . . . . . . . . . . . . . . . . . . . . . . 38
89 4.2. MAP Server as XMPP-Grid Publisher for Metadata
90 Dissemination . . . . . . . . . . . . . . . . . . . . . . 40
91 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40
92 6. Security Considerations . . . . . . . . . . . . . . . . . . . 40
93 6.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 41
94 6.1.1. Network . . . . . . . . . . . . . . . . . . . . . . . 41
95 6.1.2. XMPP-Grid Nodes . . . . . . . . . . . . . . . . . . . 41
96 6.1.3. XMPP-Grid Controller . . . . . . . . . . . . . . . . 41
97 6.1.4. Certification Authority . . . . . . . . . . . . . . . 42
98 6.2. Threat Model . . . . . . . . . . . . . . . . . . . . . . 42
99 6.2.1. Network Attacks . . . . . . . . . . . . . . . . . . . 42
100 6.2.2. XMPP-Grid Nodes . . . . . . . . . . . . . . . . . . . 43
101 6.2.3. XMPP-Grid Controllers . . . . . . . . . . . . . . . . 44
102 6.2.4. Certification Authority . . . . . . . . . . . . . . . 45
103 6.3. Countermeasures . . . . . . . . . . . . . . . . . . . . . 46
104 6.3.1. Securing the XMPP-Grid Transport Protocol . . . . . . 46
105 6.3.2. Securing XMPP-Grid Nodes . . . . . . . . . . . . . . 47
106 6.3.3. Securing XMPP-Grid Controllers . . . . . . . . . . . 48
107 6.3.4. Limit on search result size . . . . . . . . . . . . . 49
108 6.3.5. Cryptographically random session-id and
109 authentication checks for ARC . . . . . . . . . . . . 49
110 6.3.6. Securing the Certification Authority . . . . . . . . 49
111 6.4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 50
112 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 50
113 8. Evolution of XMPP-Grid . . . . . . . . . . . . . . . . . . . 51
114 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 51
115 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 51
116 10.1. Normative References . . . . . . . . . . . . . . . . . . 51
117 10.2. Informative References . . . . . . . . . . . . . . . . . 52
118 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53
120 1. Introduction
122 This document describes the extensions made to Extensible Messaging
123 and Presence Protocol (XMPP) [RFC6120]that enables use of XMPP as a
124 transport protocol for collecting and distributing security telemetry
125 information between and among network platforms, endpoints, and most
126 any network connected device. Proposed use of this transport
127 protocol is for serving use-cases outlined by the Security Automation
128 and Continuous Monitoring (SACM) working group with the IETF.
130 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
131 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
132 document are to be interpreted as described in [RFC2119].
134 Many of the terms used in this document are defined in
135 [I-D.ietf-sacm-terminology] and new ones referenced in this draft.
137 This document is being discussed on the sacm@ietf.org mailing list.
139 1.1. Glossary of Terms
141 AAA
143 Authentication, Authorization and Accounting.
145 CA
147 Certification Authority.
149 Capability Provider
151 Providers who are capable of sharing information on XMPP-Grid.
153 CMDB
155 Configuration Management Database.
157 IDS
159 Intrusion Detection System.
161 IPS
163 Intrusion Prevention System.
165 JID
167 Jabber Identifier, native address of an XMPP entity.
169 MDM
171 Mobile Device Management.
173 NAC
175 Network Admission Control.
177 PDP
179 Policy Decision Point.
181 PEP
183 Policy Enforcement Point.
185 Presence
187 XMPP-Grid node availability and online status on XMPP-Grid.
189 Publisher
191 A capability provider sharing contet information to other devices
192 participating on XMPP-Grid.
194 SIEM
196 Security Information and Event Management.
198 Subscriber
200 A device participating in XMPP-Grid and subscribing or consuming
201 information published by Publishers on XMPP-Grid.
203 Sub-Topics
205 Topic created by XMPP-Grid Controller under a capability
206 provider's topic based on message filter criteria expressed by
207 subscribers.
209 Topics
211 Contextual information channel created on XMPP-Grid where a
212 published message by the Publisher will be propagated by XMPP in
213 real-time to a set a subscribed devices.
215 VoIP
217 Voice over IP.
219 XMPP-Grid
221 Set of standards-based XMPP messages with extensions, intended for
222 use as a transport and communications protocol framework between
223 devices forming an information grid for serving SACM use-cases.
225 XMPP-Grid Controller
227 Centralized component of XMPP-Grid responsible for managing all
228 control plane operations.
230 XMPP-Grid Connection Agent
232 XMPP-Grid client library that a XMPP-Grid node implements to
233 connect and exchange information with other vendor devices on
234 XMPP-Grid.
236 XMPP-Grid Node
238 Platform or device that implements XMPP-Grid Connection Agent to
239 connect to XMPP-Grid and share or consume security data.
241 1.2. What is XMPP-Grid?
243 XMPP-Grid is a set of standards-based XMPP messages with extensions.
244 It is intended for use as a transport and communications protocol
245 framework for devices that interconnect with each other, forming an
246 information grid for serving SACM use-cases.
248 XMPP-Grid enables secure, bi-directional multi-vendor exchange of
249 contextual information between IT infrastructure platforms such as
250 security monitoring and detection systems, network policy platforms,
251 asset and configuration management, identity and access management
252 platforms. XMPP-Grid can serve to exchange any contextual security
253 information, the relevance and scope for SACM is to use XMPP-Grid to
254 exchange Posture Assessment Information; thus this draft shall use
255 the terms interchangeably. XMPP-Grid is built on top of XMPP
256 [RFC6120], [RFC6121] which is an open IETF standard messaging routing
257 protocol used in commercial platforms such as Google Voice, Jabber
258 IM, Microsoft Messenger, AOL IM and a variety of IoT and XML message
259 routing services. XMPP is also being considered as a means to
260 transport IODEF [RFC5070]. XMPP-Grid is designed for orchestration
261 of data sharing between security platforms on a many-to-many basis
262 for millions of end systems.
264 XMPP-Grid provides a security data sharing framework that enables
265 multiple vendors to integrate to XMPP-Grid once, then both share and
266 consume data bi-directionally with many IT infrastructure platforms
267 and applications from a single consistent framework akin to a
268 network-wide information bus. This reduces the need to develop to
269 explicit, multiple platform-specific interfaces, thereby increasing
270 the breadth of platforms that can interface and share security data.
271 XMPP-Grid is also configurable thereby enabling partners to share
272 only security data they want to share and consume only information
273 relevant to their platform or use-case and to customize information
274 shared without revising the interfaces. XMPP-Grid is data-agnostic
275 enabling it to operate with virtually any data type or information
276 model, but does offer optional interoperability with the Interface
277 for Metadata Access Points (IF-MAP) [IF-MAP] or with IODEF, which are
278 commonly used information repositories for security data sharing.
280 1.3. Overview of XMPP-Grid
282 XMPP-Grid employs publish/subscribe/query operations brokered by a
283 controller, which enforces access control in the system. This
284 architecture controls what platforms can connect to the "grid" to
285 share ("publish") and/or consume ("subscribe" or "query") contextual
286 information ("Topics") (described in Section 3.3 and 3.5) such as
287 security data needed to support SACM use-cases. The control of
288 publish/subscribe/query operations is architecturally distinct from
289 the actual sharing of the contextual information. Control functions
290 are split into a logical control plane, whereas information exchange
291 is considered a logical data plane. This separation enables
292 scalability and customizability.
294 XMPP-Grid defines an infrastructure protocol that hides the nuances
295 of the XMPP data plane protocol and makes the information sharing
296 models extensible with simple intuitive interfaces. XMPP-Grid Nodes
297 connect to the Grid using the XMPP-Grid Protocol. The XMPP-Grid
298 Protocol makes use of the XMPP transport protocol and introduces an
299 application layer protocol leveraging XML and XMPP extensions to
300 define the protocol.
302 The components of XMPP-Grid are:
304 o XMPP-Grid Controller (Controller): The Controller manages the
305 control plane of XMPP-Grid operations. As such it authenticates
306 and authorizes platforms connecting to the data exchange grid and
307 controls whether or not they can publish, subscribe or query
308 Topics of security data.
310 o XMPP-Grid Connection Agent (Connection Agent): The Connection
311 Agent enables the adopting Node to communicate with the Controller
312 and other vendor platforms that have adopted XMPP-Grid. Through
313 this communication privileges of the connecting platform--
314 authorization to connect, publish, subscribe, query--are
315 established. The Connection Agent is typically implemented as a
316 client library.
318 o XMPP-Grid Node (Node): A Node is a platform that has implemented
319 the Connection Agent so that it can connect to an XMPP-Grid
320 deployment to share and/or consume security data.
322 o Data Repository: This is the source of security data available on
323 the Grid and may be a network security platform, management
324 console, endpoint, etc. XMPP-Grid does not mandate a specific
325 information model, but instead remains open to transport
326 structured or unstructured data. Data may be supplied by the
327 security platform itself or by an external information repository.
329 o Topic: An XMPP-Grid Topic defines a type of security data that a
330 platform wants to share with other platform(s).
332 The operations carried out by XMPP-Grid to exchange security data
333 are:
335 o Grid Connect: This is a Controller operation that authenticates a
336 Node that has implemented the Connection Agent to establish a
337 connection with the XMPP-Grid. Once authenticated, authorization
338 policies on the Controller establish a Node's privileges on the
339 XMPP-Grid such as the right to undertake publish, subscribe or
340 query operations explained below.
342 o Publish Topic: Security information is made available when a XMPP-
343 Grid enabled platform "publishes" a "Topic". This operation is
344 authorized by the Controller and communicated to the connecting
345 platform via the Connection Agent.
347 o Topic Discovery: Nodes on a XMPP-Grid discover Topics of security
348 data relevant to them by searching the Topic directory available
349 within the XMPP-Grid deployment. The Controller maintains such a
350 Topic directory for every instance of XMPP-Grid.
352 o Subscribe to Topic: A Node seeking to consume security information
353 "subscribes" to a Topic that provides the security information it
354 seeks to serve its use-case. This operation has its authorization
355 checked by the Controller and communicated with the connecting
356 platform via the Connection Agent.
358 o Query: This operation enables a Node to request a specific set of
359 security data regarding a specific asset (such as a specific user
360 endpoint) or bulk output history from a Topic over a specific span
361 of time. Such queries can be carried out node-to-node or by
362 querying a central data repository. Query structure is adaptable
363 to match the information model in use.
365 XMPP-Grid is used to exchange security context data between systems
366 on a 1-to-1, 1-to-many, or many-to-many basis. Security data shared
367 between these systems may use pre-negotiated non-standard/native data
368 formats or may utilize an optional common information repository with
369 a standardized data format, as may be specified by SACM. XMPP-Grid
370 is data format agnostic and accommodates transport of whatever format
371 the end systems agree upon.
373 XMPP-Grid can operate in the following deployment architectures:
375 o Broker-Flow: An XMPP-Grid control plane brokers the authorization
376 and redirects the Topic subscriber to Topic publisher directly.
377 In this architecture, the Controller only manages the connection;
378 the security data flow is directly between Nodes using data
379 formats negotiated out-of-band.
381 o Centralized Data-Flow: An XMPP-Grid maintains the data within its
382 optional centralized database. In this architecture, the
383 Controller provides a common information structure for use in
384 formatting and storing security context data, such as IF-MAP, and
385 directly responds to Node publish and Subscribe requests.
387 o Proxy-Flow: An XMPP-Grid is acting as proxy, collecting the data
388 from the publisher(s) and presenting it to the subscriber
389 directly. This is used for ad-hoc queries.
391 Within the deployment architecture, XMPP-Grid may be used in any
392 combination of the following data exchange modes. The flexibility
393 afforded by the different modes enables security information to be
394 exchanged between systems in the method most suitable for serving a
395 given use-case.
397 o Continuous Topic update stream: This mode delivers in real-time
398 any data published to a Topic to the Nodes that are subscribed to
399 that Topic.
401 o Directed query: This mode enables Nodes to request a specific set
402 of security information regarding a specific asset, such as a
403 specific user endpoint.
405 o Bulk historic data query: This mode enables Nodes to request
406 transfer of past output from a Topic over a specific span of time.
408 1.4. Benefits of XMPP-Grid
410 Benefits of XMPP-Grid can be summarized on two fronts: 1) end-user
411 benefits, 2) benefits for adopting vendors.
413 Benefits for end-users deploying security services based on XMPP-Grid
414 security context information sharing capabilities are derived from
415 the results that come with standardization including:
417 o Consolidating relevant security event data from multiple systems
418 to the "right console at the right time".
420 o Cross-vendor interoperability out-of-the-box, when using a
421 standard data format.
423 o Coordinated security response across multiple products from
424 multiple vendors, ranging from endpoint security to AAA, NAC, IDS/
425 IPS, Data Loss Prevention, firewalls to infrastructure such as
426 SIEM, CMDB, physical access control systems.
428 o Customer product choice and flexibility. No need to buy all
429 security products from one vendor.
431 Adopting XMPP-Grid security data sharing capabilities provides a
432 number of benefits for adopting vendors, especially when compared to
433 proprietary interfaces, such as:
435 o Integrate the XMPP-Grid Connection Agent once to interface with
436 many platforms, simultaneously by subscribing or publishing
437 relevant security data
439 o Security information shared is configurable (via Topics) based on
440 relevance to specific use-cases and platforms
442 o Only sharing relevant data enables both publishing and subscribing
443 platforms to scale their security data sharing by eliminating
444 excess, irrelevant data
446 o Integrated authorization and security ensures only appropriate
447 XMPP-Grid operations are executed by permitted platforms
449 o Ability to share security data in native or structured formats
450 enables data model flexibility for adopting vendors
452 o Flexibility, adaptability to evolve to address new use cases over
453 time. Utilize data-agnostic transport protocol or the extensible
454 schema that allows for easy support for vendor-specific data.
456 1.5. Example Workflow
457 ______________
458 | XMPP-Grid |
459 Authorize /| Controller |\Authorize
460 / |____________| \
461 ________/ ^ \_________
462 "I have location" |Location| | | APP |"I have app info"
463 "I need app & ID.."|________|\ | /|________|"I need loc & dev"
464 \ | /
465 _\___|_____/_____
466 |Continuous Flow|
467 <-----|---------------|------>
468 | Directed Query|
469 --/------|-----\-
470 / | \
471 / | \
472 __________/ | \__________
473 "I have sec events"| SIEM | V | PAP |"I have ID & dev-type"
474 "I need ID & dev"|________| ______________ |________|"I need loc & MDM"
475 | Device Mgr |
476 |____________|
477 "I have MDM Info!"
478 "I need location..."
480 Figure 1: Typical XMPP-Grid Workflow
482 a. XMPP-Grid Controller establishes a grid for platforms wanting to
483 exchange security data.
485 b. A platform (Node) with a source of security data requests
486 connection to the Grid.
488 c. Controller authenticates and establishes authorized privileges
489 (e.g. privilege to publish and/or subscribe to security data
490 Topics) for the requesting Node.
492 d. Node may either publish a security data Topic, subscribe to a
493 security data Topic, query a Node or Topic, or any combination of
494 these operations.
496 e. Publishing Nodes unicast Topic updates to the Grid in real-time.
497 The Grid handles replication and distribution of the Topic to
498 subscribing Nodes. A Node may publish multiple Topics, thereby
499 allowing for customized relevance of the security data shared.
501 f. Subscribing Nodes receive continuous real-time stream of updates
502 to the Topic to which they are subscribed.
504 g. Any Node on the Grid may subscribe to any Topics published to the
505 Grid (as permitted by authorization policy), thereby allowing for
506 one-to-one, one-to-many and many-to-many meshed security data
507 sharing between Nodes.
509 2. Applicability of XMPP-Grid to SACM Use Cases
511 This section discusses the applicability of XMPP-Grid to the usage
512 scenarios defined in [I-D.ietf-sacm-use-cases].
514 Within the SACM use-cases, the working group has outlined four use-
515 cases and seven usage-scenarios. XMPP-Grid is applicable to each one
516 of the use-cases and usage-scenarios by following one of the three
517 main logical flows of XMPP-Grid as outlined in section 1.1.1. The
518 three flows are summarized here:
520 o Broker-Flow: XMPP-Grid brokers the authorization and redirects the
521 Topic subscriber to Topic publisher directly.
523 o Centralized Data-Flow: XMPP-Grid is maintaining the data within
524 its optional centralized database.
526 o Proxy-Flow: XMPP-Grid is acting as proxy, collecting the data from
527 the publisher(s) and presenting it to the subscriber directly.
528 This is used for ad-hoc queries.
530 Each of the seven defined usage-scenarios is listed below, along with
531 a summary of how XMPP-Grid is applicable to each use-case.
533 It is important to note that XMPP-Grid is data model agnostic, and
534 may use any information model to structure data between systems. The
535 most common standardized security information model deployed
536 currently is IF-MAP, which XMPP-Grid interoperates with today.
538 2.1. Applicability of XMPP-Grid to SACM Usage Scenarios
540 2.1.1. SACM Definition and Publication of Automatable Configuration
541 Checklists
543 XMPP-Grid is fully applicable to the usage-scenario 2.2.1 as defined
544 within the SACM use-cases document. As a vendor creates a new guide,
545 they would publish an entry describing the existence of the checklist
546 to the applicable Topic within XMPP-Grid. For the purposes of this
547 explanation, the Topic name will be "Guide".
549 Grid Nodes who are subscribed to the Topic, will receive the
550 notification of the Topic update. In response or on-demand, the Node
551 will query XMPP-Grid in order to initiate the downloading of the new
552 guide(s). The Grid Controller authorizes the download and proceeds
553 to retrieve the guide(s) from the publisher, and transfers that
554 download to the subscriber.
556 Similarly, when an administrator publishes a new checklist, they
557 would publish an entry describing the existence of the checklist to
558 the applicable Topic within XMPP-Grid. For the purposes of this
559 explanation, the Topic name will be "Checklist".
561 Grid Nodes who are subscribed to the Topic, will receive the
562 notification of the Topic update. In response or on-demand, the
563 participating entity will query XMPP-Grid in order to initiate the
564 downloading of the new checklist(s). The Grid Controller authorizes
565 the download and proceeds to retrieve the checklist(s) from the
566 publisher, and transfers that download to the subscriber. This is an
567 example of XMPP-Grid in Proxy-Flow mode.
569 2.1.2. SACM Automated Checklist Verification
571 An Endpoint Management System (EMS) publishes a Topic to XMPP-Grid
572 defining itself as an owner of Endpoint Data. Other network services
573 that are interested in endpoint data may subscribe to the Topic on
574 Endpoint Data, which is authorized by the XMPP-Grid.
576 A Baseline Service is subscribed to the Endpoint Data Topic, and has
577 a need for that updated endpoint data. The Baseline Service
578 (subscriber) requests the data from the XMPP-Grid, which authorizes
579 the retrieval and informs the subscriber of the existence of data on
580 the EMS directly. In this instance, the data transfer has been
581 authorized and occurs directly between the subscriber and the EMS.
583 The subscriber has now created new checklists and published the
584 information to the checklist Topic in XMPP-Grid. A PDP is subscribed
585 to the Checklist Topic, and is notified of the new checklists. The
586 PDP requests the data from the XMPP-Grid, which in-turn authorizes
587 the download and brokers the direct communication between the
588 Baseline Service and the PDP Directly.
590 This usage scenario is an example of XMPP-Grid in the Broker-Flow.
591 It is also showing that single entities may act as both publisher and
592 subscriber with the XMPP-Grid simultaneously.
594 2.1.3. SACM Detection of Posture Deviations
596 A user disables the firewall on a managed endpoint, which in-turn
597 sends a notice to its managing Compliance Service. The Compliance
598 Service publishes and alert to the "Alert Topic" in XMPP-Grid. There
599 is an Assessment Service, which subscribes to the Alert Topic, and is
600 therefore notified of the alert. The Assessment service consumes
601 that alert directly from the XMPP-Grid and triggers an immediate
602 assessment of the endpoint.
604 This is an example of XMPP-Grid centralized-data flow. While XMPP-
605 Grid is information model agnostic, in this scenario IF-MAP could be
606 used as the centralized data repository with XMPP-Grid providing the
607 transport in/out of the IF-MAP database..
609 2.1.4. SACM Endpoint Information Analysis and Reporting
611 There are endpoints that are uploading large quantities of data to a
612 Suspicious Server on Internet. The admin queries XMPP-Grid for the
613 posture of the endpoints. The XMPP-Grid responds with all the
614 publishers of that information along with the authorization to query
615 for the data. The admin application is now able to query the data
616 sources directly, which indicates that the applicable endpoints all
617 have certain applications installed. The admin is now able to pivot
618 the query and receive information on all other endpoints that have
619 the same application installed.
621 This usage scenario is an example of XMPP-Grid Broker-Flow.
623 2.1.5. SACM Asynchronous Compliance/Vulnerability Assessment at Ice
624 Station Zebra
626 A University Team at Ice Station Zebra registers their Equipment with
627 an Asset Management System. The university puts together a
628 collection request for all deployed assets, and sends the query to
629 the XMPP-Grid. The collection request is queued at the XMPP-Grid for
630 the next window of connectivity when the request is sent to the
631 deployed assets. The remote endpoints fulfill the request and queue
632 the results for the next return opportunity. The results are sent
633 back to the university, where they are compared against what is in
634 the Asset Management System already.
636 This is an example of XMPP-Grid centralized-data flow. While XMPP-
637 Grid is information model agnostic, in this scenario IF-MAP could be
638 used as the centralized data repository with XMPP-Grid providing the
639 transport in/out of the IF-MAP database.
641 2.1.6. SACM Identification and Retrieval of Guidance
643 There are multiple configuration services in the environment, each
644 populating a "guide" Topic in XMPP-Grid. The operator queries XMPP-
645 Grid in order to discover and consolidate a single list to be
646 compared. The XMPP-Grid replies with list of data stores, and
647 authorization to perform the queries directly to those data stores.
649 As the Admin/Operator defines search criteria, the operator is able
650 to query the data stores directly for that content, only returning to
651 the centralized XMPP-Grid when authorization is required.
653 This usage scenario is an example of XMPP-Grid in the Broker-Flow
655 2.1.7. SACM Guidance Change Detection
657 An Operator identifies content that they desire to assess, and
658 subscribes to that content Topic with XMPP-Grid. When a change to
659 that content occurs, the Operator is notified. Additionally, the
660 operator may be sent a query response. Any Data Collection and
661 evaluation Activities will also trigger an update to the operator
662 (subscriber).
664 This usage scenario is an example of XMPP-Grid centralized-data flow.
665 While XMPP-Grid is information model agnostic, in this scenario IF-
666 MAP could be used as the centralized data repository with XMPP-Grid
667 providing the transport in/out of the IF-MAP database.
669 3. XMPP-Grid Architecture
671 XMPP-Grid is a communication fabric that facilitates secure sharing
672 of information between network elements and networked applications
673 connected to the fabric both in real time and on demand.
675 XMPP-Grid uses XMPP servers that operate as a cluster with message
676 routing between them, for data plane communication. XMPP-Grid uses a
677 control plane element, the XMPP-Grid Controller, that is an external
678 component of XMPP for centralized policy-based control plane.
680 --------------- --------------- ---------------
681 | XMPP-Grid | | XMPP-Grid | | XMPP-Grid |
682 | Controller | | Controller | | Controller |
683 | | | | | |
684 --------------- --------------- ---------------
685 | | |
686 | | |
687 --------------- --------------- ---------------
688 | XMPP Server | | XMPP Server | | XMPP Server |
689 | |---------| |--------| |
690 | | | | | |
691 --------------- --------------- ---------------
693 Figure 2: XMPP Server and XMPP-Grid Cluster Architecture
694 The connected Nodes, with appropriate authorization privileges, can:
696 o Receive real-time events of the published messages from the
697 publisher through Topic subscriptions
699 o Make directed queries to other Nodes in the XMPP-Grid with
700 appropriate authorization from the Controller
702 o Negotiate out-of-band secure file transfer channel with the peer
704 This model enables flexible API usage depending on the Nodes'
705 contextual and time-sensitivity needs of security information.
707 3.1. XMPP Overview
709 XMPP is used as the foundation message routing protocol for
710 exchanging security data between systems across XMPP-Grid. XMPP is a
711 communications protocol for message-oriented middleware based on XML.
712 Designed to be extensible, the protocol uses de-centralized client-
713 server architecture where the clients connect to the servers securely
714 and the messages between the clients are routed through the XMPP
715 servers deployed within the cluster. XMPP has been used extensively
716 for publish-subscribe systems, file transfer, video, VoIP, Internet
717 of Things, Smart Grid Software Defined Networks (SDN) and other
718 collaboration and social networking applications. The following are
719 the 4 IETF specifications produced by XMPP working group:
721 o [RFC6120] Extensible Messaging and Presence Protocol (XMPP): Core
723 o [RFC6121] Extensible Messaging and Presence Protocol (XMPP):
724 Instant Messaging and Presence
726 o [RFC3922] Mapping the Extensible Messaging and Presence Protocol
727 (XMPP) to Common Presence and Instant Messaging (CPIM)
729 o [RFC3923] End-to-End Signing and Object Encryption for the
730 Extensible Messaging and Presence Protocol (XMPP)
732 XMPP offers several of the following salient features for building a
733 security data interexchange protocol:
735 o Open - standards-based, decentralized and federated architecture,
736 with no single point of failure
738 o Security - Supports domain segregations and federation. Offers
739 strong security via Simple Authentication and Security Layer
740 (SASL) [RFC4422] and Transport Layer Security (TLS) [RFC5246].
742 o Real-time event management/exchange - using publish, subscribe
743 notifications
745 o Flexibility and Extensibility - XMPP is XML based and is easily
746 extensible to adapt to new use-cases. Custom functionality can be
747 built on top of it.
749 o Multiple information exchanges - XMPP offers multiple information
750 exchange mechanisms between the participating clients -
752 o
754 * Real-time event notifications through publish and subscribe.
756 * On-demand or directed queries between the clients communicated
757 through the XMPP server
759 * Facilitates out-of-band, direct communication between
760 participating clients
762 o Bi-directional - avoids firewall tunneling and avoids opening up a
763 new connection in each direction between client and server.
765 o Scalable - supports cluster mode deployment with fan-out and
766 message routing
768 o Peer-to-peer communications also enables scale - directed queries
769 and out-of-band file transfer support
771 o XMPP offers Node availability, Node service capability discovery,
772 and Node presence within the XMPP network. Nodes ability to
773 detect the availability, presence and capabilities of other
774 participating nodes eases turnkey deployment.
776 The XMPP extensions used in XMPP-Grid are now part (e.g. publish/
777 subscribe) of the main XMPP specification [RFC6120] and the presence
778 in [RFC6121]. A full list of XMPP Extension Protocols (XEPs)
779 [RFC6120] can be found in http://xmpp.org/extensions/xep-0001.html .
781 3.2. XMPP-Grid Protocol Extensions to XMPP
783 XMPP-Grid defines an infrastructure protocol that hides the nuances
784 of the XMPP data plane protocol and makes the information sharing
785 models extensible with simple intuitive APIs. XMPP-Grid Nodes
786 connect to the Grid using the XMPP-Grid Protocol. The XMPP-Grid
787 Protocol makes use of the XMPP transport protocol and introduces an
788 application layer protocol leveraging XML and XMPP extensions to
789 define the protocol. The capability providers on the Grid extend the
790 XMPP-Grid Protocol infrastructure model and define capability
791 specific models and schemas, allowing a cleaner separation of
792 infrastructure and capabilities that can run on the infrastructure.
794 3.3. XMPP-Grid Controller Protocol Flow
796 At the heart of the XMPP-Grid network, the XMPP-Grid Controller
797 serves as the centralized policy-based control plane element managing
798 all Node authentications, authorizations, capabilities/Topics and
799 their subscription list. XMPP-Grid Controller manages all control
800 aspects of the Node communication (including management) with the
801 XMPP-Grid and other participating Nodes with mutual trust and
802 authorizations' enforcement. XMPP-Grid Controller is a component of
803 XMPP server and programs the data plane XMPP server with Node
804 accounts, account status, XMPP Topics that are dynamically created
805 and Topic subscriptions. This is analogous to File Transfer Protocol
806 (FTP) that has control and data plane communication phases. Once the
807 Node requests are authenticated and authorized in the control plane
808 phase by the Controller, the Controller removes itself from the data
809 flow. All data plane communication then occurs between the Nodes,
810 publishers and subscribers of XMPP Topics happen at the XMPP data
811 plane layer.
813 ---------------- ---------------- ----------------
814 | Publi- | Node | | Grid | XMPP | | Node | Sub- |
815 | sher |client| | Ctrlr | Srvr | |client| scriber|
816 | | | | | | | | |
817 ----------------- ----------------- -----------------
818 | Authen & allow Grid Ctrlr Comm | |
819 |<------------------------------>| |
820 | | | |
821 | |Publisher | |
822 | | Auth | |
823 | | Status | |
824 | |<---------| |
825 | | | |
826 | | | Authen & allow Grid Ctrlr |
827 | | | Communication |
828 | | |<------------------------->|
829 | | | |
830 | |Subscriber| |
831 | | Auth | |
832 | | Status & | |
833 | | Account | |
834 | |<---------| |
835 | | | |
836 | Author Publisher to | | |
837 | Topic Sequence | | |
838 --- |<------------------->| | |
839 C | | | | |
840 O | | | Add | |
841 N | | |Publisher | |
842 T | | | to Topic | |
843 R | | |--------->| |
844 O | | | | |
845 L | | | Author Subscriber to Topic Sequence |
846 --- | |<------------------------------------>|
847 | | | |
848 | | Add | |
849 | |Subscriber| |
850 | | to Topic | |
851 | |--------->| |
852 ----------------------------------------------------------------------
853 | | | |
854 | Publish Message to Topic | |
855 --- |-------------------------------->| |
856 | | | | |
857 I | | Publish Success Published Message to Subscriber |
858 N | |<----------------------------------------------------------->|
859 F | | | | |
860 R | | | | Subscribe Success |
861 A | | | |<--------------------------|
862 | | | | |
863 --- | | Topic & Publisher Discovery Request |
864 | |<-------------------------------------|
865 | | | |
866 | | Topic & Publisher JID Response |
867 | |------------------------------------->|
868 | | | |
869 | | Out-of-Band Bulk Dnld Query Reqeust |
870 | |<-------------------------------------|
871 | | | |
872 | | Out-of-Band Bulk Dnld Query Author |
873 | |------------------------------------->|
874 | | |
875 | Out-of-Band Data Bulk Byte Stream |
876 |<----------------------------------------------------------->|
878 Figure 3: XMPP Controller Message Flow
880 Through a centralized authorization model, XMPP-Grid Controller
881 provides -
882 o Visibility into "who is connecting", "who is accessing what"
884 o Node account management with provisions to add, delete or disable
885 accounts, and with provisions to auto or manual approve Node
886 account approval requests during the Node registration phase
888 o Centralized, policy-based authorization, providing "who can do
889 what" for publish-subscribe, directed peer-to-peer queries or for
890 bulk out-of-band transfers between participating Nodes
892 o Topics and subscription list management with provision to enable
893 or disable Topics
895 o Dynamic creation of sub-Topics within the main Topic depending on
896 attributes of interest from the requesting Node
898 o Ability to perform message filters on the published messages
900 3.4. XMPP-Grid Node Connection Protocol Flow
902 Nodes connecting to XMPP-Grid go through the phases of
903 authentication, registration and authorization before they can
904 participate in information exchange on XMPP-Grid.
906 3.4.1. Authentication
908 The communication between the Node and the XMPP-Grid Controller is
909 cryptographically encrypted using TLS. XMPP-Grid uses X.509
910 certificate-based mutual authentication between the Nodes and
911 Controller. Internally, XMPP uses Simple Authentication and Security
912 Layer (SASL)[RFC4422] External mechanism to authenticate and
913 establish secure tunnel with the Nodes, allowing the XMPP-Grid
914 Controller to rely on this capability offered by XMPP. If the Node
915 certificate does not pass the validation process, the connection
916 establishment is terminated with the error messages defined by the
917 XMPP standard. On successful authentication, XMPP SASL component
918 extracts the Node certificate and Node username to the Controller for
919 registration.
921 3.4.2. Registration
923 Once a Node has been authenticated and a secure tunnel has been
924 successfully established, the Nodes will register their accounts with
925 the Controller and Nodes provide their username to the Controller as
926 part of the registration request. XMPP-Grid supports manual
927 registration (requires explicit approval of the Node account) and
928 mutual authentication trust-based auto-approval registration in order
929 to provide additional trust and usability options to the
930 administrator. The administrator may map the Nodes to the Node
931 groups to add additional level of validation and trust, and enforce
932 Node group based authorization. This allows the certificate-
933 username-group trust to get uniquely establishment for each Node and
934 duplicate registration requests using the same username will be
935 rejected.
937 During the registration process, the Controller restricts all Node
938 communication with the XMPP-Grid and only Node to Controller
939 communication is allowed. Once the Node is successfully registered,
940 the Controller lifts the restriction and allows the Nodes to
941 communicate on XMPP-Grid after it passes the authorization phase. It
942 should be noted that the registered and authorized Nodes could
943 publish, subscribe or query to multiple XMPP Topics between login and
944 logout to XMPP-Grid. Multiple Node applications running on a Node
945 could use one XMPP-Grid Node to connect to XMPP-Grid. The XMPP-Grid
946 Node should support Node applications' subscription to Topics and
947 should multiplex messages on its connection to XMPP-Grid. If a Node
948 application wants to be identified explicitly on XMPP-Grid, a new
949 XMPP-Grid Node connection to XMPP-Grid is required.
951 ----------------- ---------------------------
952 | | | Grid | XMPP |
953 | Node | | Controller| Server |
954 | | | | |
955 ----------------- ---------------------------
956 | | |
957 _____| | |
958 | | | |
959 Register | | | |
960 |---->| | |
961 | TLS Connect(username, cert) | |
962 |<------------------------------------------------------>|
963 | | |
964 | | Track |
965 | |(username,cert) |
966 | |<---------------|
967 |Register(username) | |
968 |-------------------------------------->| |
969 | |___ |
970 | | | Approve & |
971 | | | Authorize |
972 | |<--| Account |
973 | | |
974 | |Create User |
975 | |Account |
976 | |(username) |
977 | |--------------->|
978 | Registration Successful | |
979 |<--------------------------------------| |
980 | | |
981 | Login() | |
982 |-------------------------------------->| |
983 | | |
984 | Pub/Sub/Query | |
985 |<------------------------------------------------------>|
986 | | |
987 | | |
988 | Logout() | |
989 |-------------------------------------->| |
990 | | |
992 Figure 4: XMPP-Grid Node Registration
994 3.4.3. Authorization
996 The registered Nodes send subscription requests to the Controller.
997 The Controller, depending on the defined authorization privileges,
998 grants permissions to subscribe and/or publish to a Topic at the
999 registration time. The Controller updates the XMPP data plane server
1000 with the new subscriber information and its capability. Node
1001 identity extracted from the request, group to which the Node is
1002 assigned during account approval and Topic/capability to which the
1003 permission is sought could be some of the ways to authorize Nodes and
1004 their requests in XMPP-Grid. Similarly, the Controller authorizes
1005 directed peer-to-peer or out-of-band requests from a requesting peer.
1006 The destination peer has options to query back the Controller to
1007 retrieve and enforce granular authorizations such as read-only,
1008 write-only, read/write.
1010 In a Query Authorization flow, the capability provider responding to
1011 the query is responsible for enforcing the authorization decision.
1012 It retrieves "is authorized" from the XMPP-Grid Controller. Based on
1013 the result, the service either allows or disallows the flow from
1014 continuing.
1016 ----------------- ----------------- -----------------
1017 | Subscriber | | XMPP-Grid | | Publisher |
1018 | | | | | |
1019 ----------------- ----------------- -----------------
1020 | | |
1021 | | |
1022 | query request |
1023 |------------------------------------------------->|
1024 | | |____
1025 | | | | extract
1026 | | | | identity
1027 | | |<---
1028 | | |
1029 | | is authorized? |
1030 | | (identity, service) |
1031 | |<------------------------|
1032 | | |
1033 | query response |
1034 |<-------------------------------------------------|
1035 | | |
1037 Figure 5: Node Query Authorization Flow
1038 For Publish Authorization, prior to allowing a publish request by a
1039 user, the XMPP-Grid Controller calls the rule evaluation engine
1040 directly for "is authorized". Based this result, the Controller
1041 either allows or disallowed the flow from continuing.
1043 ----------------- ----------------- -----------------
1044 | Publisher | | XMPP-Grid | | XMPP |
1045 | | | Controller | | Server |
1046 ----------------- ----------------- -----------------
1047 | | |
1048 | publish | |
1049 |----------------------->|____ |
1050 | | | extract |
1051 | | | identity |
1052 | |<--- |
1053 | | |
1054 | |____ |
1055 | | | is authorized? |
1056 | | | (identity,publish) |
1057 | |<--- |
1058 | | |
1059 | | publish |
1060 | |------------------------>|
1061 | | |
1063 Figure 6: Node Publish Authorization Flow
1065 For Subscribe Authorization, prior to allowing a subscribe request by
1066 a user, the XMPP-Grid Controller calls the rule evaluation engine
1067 directly for "is authorized". Based this result, the Controller
1068 either allows or disallowed the flow from continuing.
1070 ----------------- ----------------- -----------------
1071 | Subscriber | | XMPP-Grid | | XMPP |
1072 | | | Controller | | Server |
1073 ----------------- ----------------- -----------------
1074 | | |
1075 | subscribe | |
1076 |----------------------->|____ |
1077 | | | extract |
1078 | | | identity |
1079 | |<--- |
1080 | | |
1081 | |____ |
1082 | | | is authorized? |
1083 | | | (identity,publish) |
1084 | |<--- |
1085 | | |
1086 | | subscribe |
1087 | |------------------------>|
1088 | | |
1090 Figure 7: Node Subscribe Authorization Flow
1092 Bulk Data Query differs from other data transfer modes. Unlike with
1093 other modes of communication that operate in-band with the XMPP-Grid,
1094 bulk downloads occur out-of-band (over a different protocol, outside
1095 of the connection that was established with the XMPP-Grid
1096 Controller). Previously discussed authorization mechanisms are
1097 therefore not appropriate in this context.
1099 ----------------- ----------------- -----------------
1100 | Subscriber | | XMPP-Grid | | Publisher |
1101 | | | Controller | | |
1102 ----------------- ----------------- -----------------
1103 | | |
1104 | request |
1105 |------------------------------------------------->|
1106 | | |____ extract
1107 | | | | cert
1108 | | | | chain
1109 | | |<---
1110 | | is authorized |
1111 | | (cert chain, service) |
1112 | |<------------------------|
1113 | | |
1114 | response |
1115 |<-------------------------------------------------|
1116 | | |
1118 Figure 8: Node Bulk Data Query Flow
1120 Instead the bulk download service sends the certificate chain used by
1121 a Node in the TLS connection to the XMPP-Grid Controller for purposes
1122 of authenticating and authorizing the Node. Upon receiving a request
1123 with a certificate chain, the Controller checks the issuing
1124 certificate against the trust store, looks up the identity associated
1125 with the certificate, evaluates the rules, and returns "is
1126 authorized" to the service. Then the service can either allow or
1127 disallow the flow from continuing.
1129 3.5. XMPP-Grid Topics Protocol Flow
1131 For each capability, XMPP-Grid supports extensibility through XML
1132 schemas where the providers (publishers) of the capabilities define
1133 the schemas for the data exchanged. The capability provider shall
1134 also define the version, the available queries and notifications that
1135 it can support. The capability provider publishes the messages to
1136 one or more XMPP Topics, that it requests XMPP-Grid to create
1137 dynamically, depending on:
1139 a. If the capability provider has mutually exclusive schemas,
1140 different Topics will be created where the capability provider
1141 will be a publisher to each Topic with a separate schema.
1143 b. For a given Topic, if the subscribers wants to receive filtered
1144 attributes or attribute values in capability provider's published
1145 data, XMPP-Grid Controller creates sub Topics to the main Topic
1146 based on the message filters expressed. XMPP-Grid Controller
1147 enrolls the capability provider as the publisher and the
1148 requesting subscribers based on the message filter criteria they
1149 express. The capability provider will be the publisher to both
1150 the main Topic and the sub-Topics.
1152 c. In the case mentioned in (b) above, it is possible for the
1153 capability provider to just publish on the main Topic and have
1154 the XMPP-Grid Controller filter the published messages on the
1155 Controller-side and deliver attributes and attribute values of
1156 interest to the subscribers. Controller-side message filter
1157 application and the specify mechanisms such as XPATH that can be
1158 used for parsing the messages is beyond the scope of this
1159 specification.
1161 3.5.1. Topic Versioning
1163 XMPP-Grid supports versioning to support forward and backward
1164 compatible information models. The providers of capability include
1165 the version number in the messages they publish and the receiving
1166 Nodes can interpret the Topic version and process the attributes
1167 accordingly. The expectation is any new version of a capability must
1168 be of additive updates only. In other words, existing elements and
1169 attributes cannot be changed, only new elements or attributes can be
1170 added. This will enable nodes with older capability be able to
1171 process newer version. The extra new elements or attributes will be
1172 ignored. Instead of using the same Topic for all versions, it is
1173 possible in XMPP-Grid to programmatically create separate Topics for
1174 each version and allow them to be discovered and subscribed by the
1175 Nodes.
1177 In XMPP-Grid, versioning support applies equally to both publish/
1178 subscribe, directed and out-of-band queries.
1180 3.5.2. Topic Discovery
1182 The Nodes connected to XMPP-Grid can query the Controller and get the
1183 list of all capabilities/Topics running on XMPP-Grid. The XML
1184 samples provided in XMPP-Grid Protocol section above provide
1185 illustrations of Capability Query and Capability Provider Query.
1187 3.5.3. Subtopics and Message Filters
1189 XMPP-Grid supports semantic message filtering for Topics. The
1190 content being published by a provider can be semantically grouped
1191 into categories based on domain, location of endpoints for example.
1192 The provider of a capability specifies whether it supports semantic
1193 filtering or not to the Controller at the subscribe time to the Topic
1194 under consideration.
1196 XMPP-Grid subscribers query the Controller and obtain the filtering
1197 options available for each capability, and express their message
1198 filtering criteria at subscription time. The Controller, for each
1199 unique filter criteria specified by the subscribers, creates a new
1200 sub Topic under the main capability Topic. All the subscribers with
1201 the same filtering criteria will be subscribed to the Subtopic. The
1202 set of filter criteria for a capability will be predefined by the
1203 capability provider and could be based on the well-defined attributes
1204 of the message.
1206 ----------------- --------------------------- --------------
1207 | | | Grid | XMPP | | Capability |
1208 | Node | | Controller| Server | | Provider |
1209 | | | | | | |
1210 ----------------- --------------------------- --------------
1211 | | | |
1212 |Subscribe with filter | |
1213 |------------------->|____ | |
1214 | | | translate & | |
1215 | | | validate | |
1216 | |<---- filter | |
1217 | |____ | |
1218 | | | Check if sub-topic |
1219 | | | for filter | |
1220 | |<--- exists | |
1221 | | | |
1222 | |Create subtopic if doesn't exist |
1223 | |--------------------->| |
1224 | | | |
1225 | |Add Pub & Sub to Sub-Topic |
1226 | |--------------------->| |
1227 | | | |
1228 | |Notify Publisher | |
1229 | |------------------------------------->|
1230 | Subscribe Success | | |
1231 |<-------------------| | |
1232 | | | |
1234 Figure 9: Subtopics and Information Filter Subscribe Operations Flow
1236 The publisher will be responsible for applying the filter on the
1237 message and publishing the message on the Topic and the Subtopic
1238 based on the filter criteria. Filtering logic will be on the
1239 publisher, as the publisher understands the message content. XMPP-
1240 Grid fabric is oblivious to the message content.
1242 To avoid proliferation of new Subtopics, the capability provider
1243 could express the configurable limit on the number of Subtopics that
1244 can be created for its capability at registration time. The XMPP-
1245 Grid Controller will perform periodic cleanup of Subtopics whenever
1246 their subscription list reduces to 0.
1248 In XMPP-Grid, message filters are provided to all APIs i.e. publish/
1249 subscribe and directed query.
1251 ----------------- --------------------------- --------------
1252 | Capability | | Grid | XMPP | | |
1253 | Provider | | Controller| Server | | Node |
1254 | | | | | | |
1255 ----------------- --------------------------- --------------
1256 | | | |
1257 | Register as Publisher | |
1258 |------------------->| | |
1259 | |Add Publisher to main | |
1260 | |topic & all subtopics | |
1261 | |--------------------->| |
1262 |Return registration | | |
1263 |success & list of | | |
1264 |subtopics with | | |
1265 |filtering criteria | | |
1266 |<-------------------| | |
1267 | | | |
1268 |Publish message to | | |
1269 |main topic | | |
1270 |------------------->| | |
1271 Check |____ |Publish message to | |
1272 filtering| | |main topic | |
1273 criteria & | |--------------------->| |
1274 identity |<--- | | |
1275 | | | |
1276 |Publish message to | | |
1277 |subtopic that matched filter | |
1278 |------------------------------------------>| |
1279 | | | Notify |
1280 | | |-------------->|
1282 Figure 10: Subtopic Publish Operations Flow
1284 3.6. XMPP-Grid Protocol Details
1286 The XMPP-Grid Protocol provides provides an abstraction layer over
1287 and above XMPP messages with the intent to provide intuitive
1288 interfaces to the Nodes connecting to XMPP-Grid. Nodes connecting to
1289 XMPP-Grid use the following interfaces (provided as XML samples)
1290 offered by XMPP-Grid protocol to connect and participate in
1291 information exchange on XMPP-Grid:
1293 o Register the Node to XMPP-Grid: Node identified as
1294 "Node2@domain.com/mac" sends the following Registration request to
1295 XMPP-Grid controller.
1297
1299
1300
1301
1302
1303
1305 o Node login to XMPP-Grid: The following XML sample shows the Login
1306 request from Node "Node2@domain.com/mac" to XMPP-Grid controller and
1307 Login response returned by the XMPP-Grid controller to the Node.
1309 // Request
1310
1312
1313
1314
1315
1316
1317
1319 // Response
1320
1322
1323
1324
1325
1326
1327
1328
1329
1331 o Node logout from XMPP-Grid: The following XML sample shows the
1332 Logout request sent by Node "Node2@domain.com/mac" to XMPP-Grid
1333 controller.
1335
1337
1338
1339
1340
1341
1342
1344 o Capability Discovery Query: The following XML sample shows the
1345 Capability Discovery query request from Node "Node2@domain.com/mac"
1346 to XMPP-Grid controller. The XMPP-Grid controller returns the list
1347 of capabilities supported by XMPP-Grid and their versions as a
1348 response to the Node's request.
1350 // Request
1351
1353
1354
1356
1357
1359 // Response
1360
1362
1363
1365
1367 0
1368 TrustSecMetaDataCapability-1.0
1369 1.0
1370
1371
1373 0
1374
1375 EndpointProfileMetaDataCapability-1.0
1376 1.0
1377
1378
1380 0
1381 IdentityGroupCapability-1.0
1382 1.0
1383
1384
1386 0
1387 TDAnalysisServiceCapability-1.0
1388 1.0
1389
1390
1392 0
1393 NetworkCaptureCapability-1.0
1394 1.0
1395
1396
1398 0
1399
1400 EndpointProtectionServiceCapability-1.0
1401 1.0
1402
1403
1405 0
1406
1407 GridControllerAdminServiceCapability-1.0
1408 1.0
1409
1410
1412 0
1413 SessionDirectoryCapability-1.0
1414 1.0
1415
1416
1417
1418
1419 o Specific Capability Provider Query: The following XML sample shows
1420 the Capability Provider hostname query request from Node
1421 "Node2@domain.com/mac" to XMPP-Grid controller. XMPP-Grid controller
1422 returns the hostname of the specific Capability Provider as a
1423 response to the Node's request.
1425 // Request
1426
1428
1429
1430
1456
1457
1459
1478
1479
1493
1494
1517
1518
1520
1521 user1
1522
1523
1524
1525
1527 // Query Response
1528
1530
1531
1533
1534 user1
1535
1536
1537 User Identity Groups:Employee
1538
1539 Identity
1540
1541
1542
1543
1544
1545
1547 4. XMPP-Grid Compatibility with IF-MAP Information Model
1549 As mentioned throughout this document, XMPP-Grid is information model
1550 and data format agnostic, as it focuses on transport of security
1551 context data. There are, however, deployment scenarios where
1552 accessing data in a common format in a consistent information model
1553 will be required for serving SACM use-cases. The most prevalent
1554 standards-based model for such deployments is IF-MAP, thus an XMPP-
1555 Grid/IF-MAP compatibility discussion is salient for this document.
1557 The Trusted Network Connect Working Group (TNC-WG) has defined an
1558 open solution architecture [IF-MAP] that enables network operators to
1559 enforce policies regarding the security state of endpoints in order
1560 to determine whether to grant access to a requested network
1561 infrastructure. Part of the TNC architecture is IF-MAP, a standard
1562 interface between the Metadata Access Point and other elements of the
1563 TNC architecture. Readers who wish to understand in detail and
1564 implement IF-MAP are encouraged to review the following documents:
1566 o [IF-MAP]Trusted Computing Group, TNC Architecture for
1567 Interoperability, Revision 1.5, May 2012
1569 o [IF-MAP-SOAP]Trusted Computing Group, TNC IF-MAP Binding for SOAP,
1570 Revision 2.2, March 2014
1572 o [IF-MAP-NETSEC]Trusted Computing Group, TNC IF-MAP Metadata for
1573 Network Security, Revision 1.0, August 2010
1575 o [IF-MAP-ICS]Trusted Computing Group, TNC IF-MAP Metadata for ICS,
1576 Security, Revision 1.0, October 2012
1578 From a compatibility perspective, XMPP-Grid can substitute the SOAP-
1579 based IF-MAP standard interface between the MAP server and other
1580 elements in the network, thereby providing the information transport
1581 between IF-MAP clients. This substitution delivers greater
1582 scalability and timely data, as well as backwards compatibility with
1583 IF-MAP deployments. The IF-MAP data data (Topics and Subtopics can
1584 be created based on IF-MAP data models) and operation models
1585 (interfaces, message filters could be defined for the Topics and
1586 Subtopics based on the IF-MAP operations supported for the use-cases
1587 developed for use-cases such as network security can be overlaid on
1588 XMPP-Grid transport thereby achieving model consistency for both IF-
1589 MAP enabled and XMPP-Grid enabled network deployment scenarios. The
1590 MAP Server will be the participant in both the IF-MAP enabled network
1591 and the XMPP-Grid enabled network serving as aggregator and publisher
1592 of information.
1594 IF-MAP Enabled Devices
1595 ____________ ___________ _____________
1596 |__________|_ | | IF-MAP | Flow |
1597 || _________|_ | |<-------->|Controllers|
1598 || | | IF-MAP | | |___________|
1599 -|_| PDP |<-------->| |
1600 |_________| | | _____________
1601 | MAP | IF-MAP | |
1602 ____________ | Server |<-------->| Sensors |
1603 |__________|_ | | |___________|
1604 || _________|_ | | _____________
1605 || | | IF-MAP | | IF-MAP | |
1606 -|_| PEP |<-------->| |<-------->| Others |
1607 |_________| |_________| |___________|
1608 ^
1609 |
1610 | Grid
1611 XMPP-Grid Enabled Devices |
1612 ____________ _____V_____ _____________
1613 |__________|_ | | Grid | Flow |
1614 || _________|_ | |<-------->|Controllers|
1615 || | | Grid | | |___________|
1616 -|_| PDP |<-------->| Grid |
1617 |_________| | Server | _____________
1618 | Cluster | Grid | |
1619 ____________ | |<-------->| Sensors |
1620 |__________|_ | | |___________|
1621 || _________|_ |_________| _____________
1622 || | | | |
1623 -|_| PEP | GRID | Others |
1624 |_________|<----------------------------->|___________|
1626 Figure 11: XMPP-Grid and IF-MAP Interoperability
1628 The MAP server will be a XMPP-Grid Node connected to the XMPP-Grid
1629 Controller. The MAP server will play the role of subscribers and/or
1630 publishers depending on the MAP graphs and the contextual metadata to
1631 be aggregated and/or published.
1633 4.1. MAP Server as XMPP-Grid Subscriber for Metadata Aggregation
1635 The MAP Server will be a subscriber when aggregating metadata from
1636 various XMPP-Grid-enabled PEPs and PDPs in the network. Topics will
1637 be created in XMPP-Grid depending on the metadata to be aggregated,
1638 how relational or disjoint the metadata types, metadata-identifier
1639 linkages in IF-MAP graph are and the publishers of the data such as
1640 the Access Requestors, PEPs and PDPs. As discussed in the Topics
1641 section earlier, XMPP-Grid provides the ability to the Capability
1642 provider to create main Topics and Subtopics. The MAP server will be
1643 a subscriber to all of the Topics created for such purposes of
1644 aggregation. It is the responsibility of the MAP server to use the
1645 subscribed metadata to build and manage the MAP graphs.
1647 XMPP-Grid architecture allows multiple MAP servers to be subscribers
1648 to the Topics and also other network elements such as Flow
1649 Controllers and Sensors to directly consume information from the
1650 sources. This enables a complete decentralized architecture for IF-
1651 MAP for metadata aggregation where the MAP Server need not always be
1652 the sole publisher of metadata for the MAP graph. With such approach
1653 it will be possible for time-sensitive subscribers to directly
1654 consume information from the sources and use the MAP server for query
1655 and search purposes only, enabling the MAP servers to scale
1656 significantly. This also allows aggregation of metadata based on
1657 domains where MAP server can aggregate and publish metadata based on
1658 domain, and subscribers could use message filters such as domain,
1659 location to receive only metadata of interest to them.
1661 Region 1 Region 2
1662 ___________ ___________
1663 | | | |
1664 | MAP | | MAP |
1665 | Server | | Server |
1666 ____________ | | | | ___________
1667 |__________|_ |_________| |_________| _|_________|
1668 || _________|_ ^ ^ _|_________||
1669 || | | Grid | | Grid | ||-
1670 -|_| PDP |<-----------| |Grid Grid| |----------->| PDP |-
1671 |_________| | | | | |_________|
1672 ____________ __V__V_____ ______V__V__ ___________
1673 |__________|_ | | | | _|_________|
1674 || _________|_ | | | | _|_________||
1675 || | | Grid | | | | Grid | ||-
1676 -|_| PEP |<-------->| | | |<-------->| PEP |-
1677 |_________| | | | | |_________|
1678 _____________ | Grid | Grid | Grid | _____________
1679 | Flow | Grid | Server |<---->| Server | Grid | Flow |
1680 |Controllers|<--------->| | | |<--------->|Controllers|
1681 |___________| | | | | |___________|
1682 _____________ | | | | _____________
1683 | | Grid | | | | Grid | |
1684 | Sensors |<--------->| | | |<--------->| Sensors |
1685 |___________| |_________| |__________| |___________|
1687 Figure 12: XMPP-Grid Bridging Multiple IF-MAP Instances
1689 4.2. MAP Server as XMPP-Grid Publisher for Metadata Dissemination
1691 MAP Server could publish the MAP graph attribute changes to
1692 interested subscribers such as Flow Controllers, Sensors in the
1693 following ways
1695 a. MAP Server to publish all attribute changes of a MAP graph on a
1696 main Topic to which the interested network elements participate
1697 as subscribers. The subscribers will be able to get real-time
1698 notifications through Publish-Subscribe and make on-demand peer-
1699 to-peer directed or bulk queries depending on their authorization
1700 privileges.
1702 b. In addition, MAP server, at registration time with XMPP-Grid,
1703 could register the MAP graph's filtering criteria as a Publisher
1704 with XMPP-Grid. The filtering criteria of a MAP graph could be
1705 based on a combination of -
1707 A. metadata types
1709 B. metadata-identifier linkage attributes
1711 C. metadata class
1713 D. existing IF-MAP search criteria
1715 As discussed in the Topics section, XMPP-Grid Controller will create
1716 Subtopics and manage the Subtopics through the lifecycle based on the
1717 subscription list. The MAP Server and XMPP-Grid applies the message
1718 filters to publish-subscribe, directed or bulk queries made by the
1719 subscribers.
1721 5. IANA Considerations
1723 IANA Considerations to be determined
1725 6. Security Considerations
1727 A XMPP-Grid Controller serves as an controlling broker for XMPP-Grid
1728 Nodes such as Enforcement Points, Policy Servers, CMDBs, and Sensors,
1729 using a publish-subscribe-search model of information exchange and
1730 lookup. By increasing the ability of XMPP-Grid Nodes to learn about
1731 and respond to security-relevant events and data, XMPP-Grid can
1732 improve the timeliness and utility of the security system. However,
1733 this integrated security system can also be exploited by attackers if
1734 they can compromise it. Therefore, strong security protections for
1735 XMPP-Grid are essential.
1737 This section provides a security analysis of the XMPP-Grid transport
1738 protocol and the architectural elements that employ it, specifically
1739 with respect to their use of this protocol. Three subsections define
1740 the trust model (which elements are trusted to do what), the threat
1741 model (attacks that may be mounted on the system), and the
1742 countermeasures (ways to address or mitigate the threats previously
1743 identified).
1745 6.1. Trust Model
1747 The first step in analyzing the security of the XMPP-Grid transport
1748 protocol is to describe the trust model, listing what each
1749 architectural element is trusted to do. The items listed here are
1750 assumptions, but provisions are made in the Threat Model and
1751 Countermeasures sections for elements that fail to perform as they
1752 were trusted to do.
1754 6.1.1. Network
1756 The network used to carry XMPP-Grid messages is trusted to:
1758 o Perform best effort delivery of network traffic
1760 The network used to carry XMPP-Grid messages is not expected
1761 (trusted) to:
1763 o Provide confidentiality or integrity protection for messages sent
1764 over it
1766 o Provide timely or reliable service
1768 6.1.2. XMPP-Grid Nodes
1770 Authorized XMPP-Grid Nodes are trusted to:
1772 o Preserve the confidentiality of sensitive data retrieved via the
1773 XMPP-Grid Controller
1775 6.1.3. XMPP-Grid Controller
1777 The XMPP-Grid Controller is trusted to:
1779 o Broker requests for data and enforce authorization of access to
1780 this data throughout its lifecycle
1782 o Perform service requests in a timely and accurate manner
1784 o Create and maintain accurate operational attributes
1785 o Only reveal data to and accept service requests from authorized
1786 parties
1788 The XMPP-Grid Controller is not expected (trusted) to:
1790 o Verify the truth (correctness) of data
1792 6.1.4. Certification Authority
1794 The Certification Authority (CA) that issues certificates for the
1795 XMPP-Grid Controller and/or XMPP-Grid Nodes (or each CA, if there are
1796 several) is trusted to:
1798 o Protect the confidentiality of the CA's private key
1800 o Ensure that only proper certificates are issued and that all
1801 certificates are issued in accordance with the CA's policies
1803 o Revoke certificates previously issued when necessary
1805 o Regularly and securely distribute certificate revocation
1806 information
1808 o Promptly detect and report any violations of this trust so that
1809 they can be handled
1811 The CA is not expected (trusted) to:
1813 o Issue certificates that go beyond name constraints or other
1814 constraints imposed by a relying party or a cross-certificate
1816 6.2. Threat Model
1818 To secure the XMPP-Grid transport protocol and the architectural
1819 elements that implement it, this section identifies the attacks that
1820 can be mounted against the protocol and elements.
1822 6.2.1. Network Attacks
1824 A variety of attacks can be mounted using the network. For the
1825 purposes of this subsection the phrase "network traffic" should be
1826 taken to mean messages and/or parts of messages. Any of these
1827 attacks may be mounted by network elements, by parties who control
1828 network elements, and (in many cases) by parties who control network-
1829 attached devices.
1831 o Network traffic may be passively monitored to glean information
1832 from any unencrypted traffic
1834 o Even if all traffic is encrypted, valuable information can be
1835 gained by traffic analysis (volume, timing, source and destination
1836 addresses, etc.)
1838 o Network traffic may be modified in transit
1840 o Previously transmitted network traffic may be replayed
1842 o New network traffic may be added
1844 o Network traffic may be blocked, perhaps selectively
1846 o A "Man In The Middle" (MITM) attack may be mounted where an
1847 attacker interposes itself between two communicating parties and
1848 poses as the other end to either party or impersonates the other
1849 end to either or both parties
1851 o Resist attacks (including denial of service and other attacks from
1852 XMPP-Grid Nodes)
1854 o Undesired network traffic may be sent in an effort to overload an
1855 architectural component, thus mounting a denial of service attack
1857 6.2.2. XMPP-Grid Nodes
1859 An unauthorized XMPP-Grid Nodes (one which is not recognized by the
1860 XMPP-Grid Controller or is recognized but not authorized to perform
1861 any actions) cannot mount any attacks other than those listed in the
1862 Network Attacks section above.
1864 An authorized XMPP-Grid Node, on the other hand, can mount many
1865 attacks. These attacks might occur because the XMPP-Grid Node is
1866 controlled by a malicious, careless, or incompetent party (whether
1867 because its owner is malicious, careless, or incompetent or because
1868 the XMPP-Grid Node has been compromised and is now controlled by a
1869 party other than its owner). They might also occur because the XMPP-
1870 Grid Node is running malicious software; because the XMPP-Grid Node
1871 is running buggy software (which may fail in a state that floods the
1872 network with traffic); or because the XMPP-Grid Node has been
1873 configured improperly. From a security standpoint, it generally
1874 makes no difference why an attack is initiated. The same
1875 countermeasures can be employed in any case.
1877 Here is a list of attacks that may be mounted by an authorized XMPP-
1878 Grid Node:
1880 o Cause many false alarms or otherwise overload the XMPP-Grid
1881 Controller or other elements in the network security system
1882 (including human administrators) leading to a denial of service or
1883 disabling parts of the network security system
1885 o Omit important actions (such as posting incriminating data),
1886 resulting in incorrect access
1888 o Use confidential information obtained from the XMPP-Grid
1889 Controller to enable further attacks (such as using endpoint
1890 health check results to exploit vulnerable endpoints)
1892 o Advertise data crafted to exploit vulnerabilities in the XMPP-Grid
1893 Controller or in other XMPP-Grid Nodes, with a goal of
1894 compromising those systems
1896 o Issue a search request or set up a subscription that matches an
1897 enormous result, leading to resource exhaustion on the XMPP-Grid
1898 Controller, the publishing XMPP-Grid Node, and/or the network
1900 o Establish a communication channel using another XMPP-Grid Node's
1901 session-id
1903 Dependencies of or vulnerabilities of authorized XMPP-Grid Nodes may
1904 be exploited to effect these attacks. Another way to effect these
1905 attacks is to gain the ability to impersonate a XMPP-Grid Node
1906 (through theft of the XMPP-Grid Node's identity credentials or
1907 through other means). Even a clock skew between the XMPP-Grid Node
1908 and XMPP-Grid Controller can cause problems if the XMPP-Grid Node
1909 assumes that old XMPP-Grid Node data should be ignored.
1911 6.2.3. XMPP-Grid Controllers
1913 An unauthorized XMPP-Grid Controller (one which is not trusted by
1914 XMPP-Grid Nodes) cannot mount any attacks other than those listed in
1915 the Network Attacks section above.
1917 An authorized XMPP-Grid Controller can mount many attacks. Similar
1918 to the XMPP-Grid Node case described above, these attacks might occur
1919 because the XMPP-Grid Controller is controlled by a malicious,
1920 careless, or incompetent party (either a XMPP-Grid Controller
1921 administrator or an attacker who has seized control of the XMPP-Grid
1922 Controller). They might also occur because the XMPP-Grid Controller
1923 is running malicious software, because the XMPP-Grid Controller is
1924 running buggy software (which may fail in a state that corrupts data
1925 or floods the network with traffic), or because the XMPP-Grid
1926 Controller has been configured improperly.
1928 All of the attacks listed for XMPP-Grid Node above can be mounted by
1929 the XMPP-Grid Controller. Detection of these attacks will be more
1930 difficult since the XMPP-Grid Controller can create false operational
1931 attributes and/or logs that imply some other party created any bad
1932 data.
1934 Additional XMPP-Grid Controller attacks may include:
1936 o Expose different data to different XMPP-Grid Nodes to mislead
1937 investigators or cause inconsistent behavior
1939 o Mount an even more effective denial of service attack than a
1940 single XMPP-Grid Node could
1942 o Obtain and cache XMPP-Grid Node credentials so they can be used to
1943 impersonate XMPP-Grid Nodes even after a breach of the XMPP-Grid
1944 Controller is repaired
1946 o Obtain and cache XMPP-Grid Controller administrator credentials so
1947 they can be used to regain control of the XMPP-Grid Controller
1948 after the breach of the XMPP-Grid Controller is repaired
1950 Dependencies of or vulnerabilities of the XMPP-Grid Controller may be
1951 exploited to obtain control of the XMPP-Grid Controller and effect
1952 these attacks.
1954 6.2.4. Certification Authority
1956 A Certification Authority trusted to issue certificates for the XMPP-
1957 Grid Controller and/or XMPP-Grid Nodes can mount several attacks:
1959 o Issue certificates for unauthorized parties, enabling them to
1960 impersonate authorized parties such as the XMPP-Grid Controller or
1961 a XMPP-Grid Node. This can lead to all the threats that can be
1962 mounted by the certificate's subject.
1964 o Issue certificates without following all of the CA's policies.
1965 Because this can result in issuing certificates that may be used
1966 to impersonate authorized parties, this can lead to all the
1967 threats that can be mounted by the certificate's subject.
1969 o Fail to revoke previously issued certificates that need to be
1970 revoked. This can lead to undetected impersonation of the
1971 certificate's subject or failure to revoke authorization of the
1972 subject, and therefore can lead to all of the threats that can be
1973 mounted by that subject.
1975 o Fail to regularly and securely distribute certificate revocation
1976 information. This may cause a relying party to accept a revoked
1977 certificate, leading to undetected impersonation of the
1978 certificate's subject or failure to revoke authorization of the
1979 subject, and therefore can lead to all of the threats that can be
1980 mounted by that subject. It can also cause a relying party to
1981 refuse to proceed with a transaction because timely revocation
1982 information is not available, even though the transaction should
1983 be permitted to proceed.
1985 o Allow the CA's private key to be revealed to an unauthorized
1986 party. This can lead to all the threats above. Even worse, the
1987 actions taken with the private key will not be known to the CA.
1989 o Fail to promptly detect and report errors and violations of trust
1990 so that relying parties can be promptly notified. This can cause
1991 the threats listed earlier in this section to persist longer than
1992 necessary, leading to many knock-on effects.
1994 6.3. Countermeasures
1996 Below are countermeasures for specific attack scenarios to the XMPP-
1997 Grid infrastructure.
1999 6.3.1. Securing the XMPP-Grid Transport Protocol
2001 To address network attacks, the XMPP-Grid transport protocol
2002 described in this document requires that the XMPP-Grid messages MUST
2003 be carried over TLS (minimally TLS 1.2 [RFC5246]) as described in
2004 [RFC2818]. The XMPP-Grid Node MUST verify the XMPP-Grid Controller's
2005 certificate and determine whether the XMPP-Grid Controller is trusted
2006 by this XMPP-Grid Node before completing the TLS handshake. The
2007 XMPP-Grid Controller MUST authenticate the XMPP-Grid Node either
2008 using mutual certificate-based authentication in the TLS handshake or
2009 using Basic Authentication as described in IETF RFC 2617. XMPP-Grid
2010 Controller MUST use Simple Authentication and Security Layer (SASL),
2011 described in [RFC4422], to support the aforesaid authentication
2012 mechanisms. SASL offers authentication mechanism negotiations
2013 between the XMPP-Grid Controller and XMPP-Grid node during the
2014 connection establishment phase. XMPP-Grid Nodes and XMPP-Grid
2015 Controllers using mutual certificate-based authentication SHOULD each
2016 verify the revocation status of the other party. All XMPP-Grid
2017 Controllers and XMPP-Grid Nodes MUST implement both mutual
2018 certificate-based authentication and Basic Authentication. The
2019 selection of which XMPP-Grid Node authentication technique to use in
2020 any particular deployment is left to the administrator.
2022 An XMPP-Grid Controller MAY also support a local, configurable set of
2023 Basic Authentication userid-password pairs. If so, it is
2024 implementation dependent whether a XMPP-Grid Controller ends a
2025 session when an administrator changes the configured password. Since
2026 Basic Authentication has many security disadvantages (especially the
2027 transmission of reusable XMPP-Grid Node passwords to the XMPP-Grid
2028 Controller), it SHOULD only be used when absolutely necessary. Per
2029 the HTTP specification, when basic authentication is in use, a XMPP-
2030 Grid Controller MAY respond to any request that lacks credentials
2031 with an error code similar to HTTP code 401. A XMPP-Grid Node SHOULD
2032 avoid this code by submitting basic auth credentials with every
2033 request when basic authentication is in use. If it does not do so, a
2034 XMPP-Grid Node MUST respond to this code by resubmitting the same
2035 request with credentials (unless the XMPP-Grid Node is shutting
2036 down).
2038 As XMPP uses TLS as the transport and security mechanisms, it is
2039 understood that best practices such as those in
2040 [I-D.ietf-uta-tls-bcp] are followed.
2042 These protocol security measures provide protection against all the
2043 network attacks listed in the above document section except denial of
2044 service attacks. If protection against these denial of service
2045 attacks is desired, ingress filtering, rate limiting per source IP
2046 address, and other denial of service mitigation measures may be
2047 employed. In addition, a XMPP-Grid Controller MAY automatically
2048 disable a misbehaving XMPP-Grid Node.
2050 6.3.2. Securing XMPP-Grid Nodes
2052 XMPP-Grid Nodes may be deployed in locations that are susceptible to
2053 physical attacks. Physical security measures may be taken to avoid
2054 compromise of XMPP-Grid Nodes, but these may not always be practical
2055 or completely effective. An alternative measure is to configure the
2056 XMPP-Grid Controller to provide read-only access for such systems.
2057 The XMPP-Grid Controller SHOULD also include a full authorization
2058 model so that individual XMPP-Grid Nodes may be configured to have
2059 only the privileges that they need. The XMPP-Grid Controller MAY
2060 provide functional templates so that the administrator can configure
2061 a specific XMPP-Grid Node as a DHCP server and authorize only the
2062 operations and metadata types needed by a DHCP server to be permitted
2063 for that XMPP-Grid Node. These techniques can reduce the negative
2064 impacts of a compromised XMPP-Grid Node without diminishing the
2065 utility of the overall system.
2067 To handle attacks within the bounds of this authorization model, the
2068 XMPP-Grid Controller MAY also include rate limits and alerts for
2069 unusual XMPP-Grid Node behavior. XMPP-Grid Controllers SHOULD make
2070 it easy to revoke a XMPP-Grid Node's authorization when necessary.
2071 Another way to detect attacks from XMPP-Grid Nodes is to create fake
2072 entries in the available data (honeytokens) which normal XMPP-Grid
2073 Nodes will not attempt to access. The XMPP-Grid Controller SHOULD
2074 include auditable logs of XMPP-Grid Node activities.
2076 To avoid compromise of XMPP-Grid Node, XMPP-Grid Node SHOULD be
2077 hardened against attack and minimized to reduce their attack surface.
2078 They SHOULD go through a TNC handshake to verify the integrity of the
2079 XMPP-Grid Node, and SHOULD, if feasible, utilize a Trusted Platform
2080 Module (TPM) for identity and/or integrity measurements of the XMPP-
2081 Grid Node within a TNC handshake. They should be well managed to
2082 minimize vulnerabilities in the underlying platform and in systems
2083 upon which the XMPP-Grid Node depends. Personnel with administrative
2084 access should be carefully screened and monitored to detect problems
2085 as soon as possible.
2087 6.3.3. Securing XMPP-Grid Controllers
2089 Because of the serious consequences of XMPP-Grid Controller
2090 compromise, XMPP-Grid Controllers SHOULD be especially well hardened
2091 against attack and minimized to reduce their attack surface. They
2092 SHOULD go through a regular TNC handshake to verify the integrity of
2093 the XMPP-Grid Controller, and SHOULD utilize a Trusted Platform
2094 Module (TPM) for identity and/or integrity measurements of the XMPP-
2095 Grid Node within a TNC handshake. They should be well managed to
2096 minimize vulnerabilities in the underlying platform and in systems
2097 upon which the XMPP-Grid Controller depends. Network security
2098 measures such as firewalls or intrusion detection systems may be used
2099 to monitor and limit traffic to and from the XMPP-Grid Controller.
2100 Personnel with administrative access should be carefully screened and
2101 monitored to detect problems as soon as possible. Administrators
2102 should not use password-based authentication but should instead use
2103 non-reusable credentials and multi-factor authentication (where
2104 available). Physical security measures SHOULD be employed to prevent
2105 physical attacks on XMPP-Grid Controllers.
2107 To ease detection of XMPP-Grid Controller compromise should it occur,
2108 XMPP-Grid Controller behavior should be monitored to detect unusual
2109 behavior (such as a reboot, a large increase in traffic, or different
2110 views of an information repository for similar XMPP-Grid Nodes).
2111 XMPP-Grid Nodes should log and/or notify administrators when peculiar
2112 XMPP-Grid Controller behavior is detected. To aid forensic
2113 investigation, permanent read-only audit logs of security-relevant
2114 information (especially administrative actions) should be maintained.
2115 If XMPP-Grid Controller compromise is detected, a careful analysis
2116 should be performed of the impact of this compromise. Any reusable
2117 credentials that may have been compromised should be reissued.
2119 6.3.4. Limit on search result size
2121 While XMPP-Grid is designed for high scalability to 100,000s of
2122 Nodes, an XMPP-Grid Controller MAY establish a limit to the amount of
2123 data it is willing to return in search or subscription results. This
2124 mitigates the threat of a XMPP-Grid Node causing resource exhaustion
2125 by issuing a search or subscription that leads to an enormous result.
2127 6.3.5. Cryptographically random session-id and authentication checks
2128 for ARC
2130 A XMPP-Grid Controller SHOULD ensure that the XMPP-Grid Node
2131 establishing an ARC is the same XMPP-Grid Node as the XMPP-Grid Node
2132 that established the corresponding SSRC. The XMPP-Grid Controller
2133 SHOULD employ both of the following strategies:
2135 o session-ids SHOULD be cryptographically random
2137 o The HTTPS transport for the SSRC and the ARC SHOULD be
2138 authenticated using the same credentials. SSL session resumption
2139 MAY be used to establish the ARC based on the SSRC SSL session.
2141 6.3.6. Securing the Certification Authority
2143 As noted above, compromise of a Certification Authority (CA) trusted
2144 to issue certificates for the XMPP-Grid Controller and/or XMPP-Grid
2145 Nodes is a major security breach. Many guidelines for proper CA
2146 security have been developed: the CA/Browser Forum's Baseline
2147 Requirements, the AICPA/CICA Trust Service Principles, etc. The CA
2148 operator and relying parties should agree on an appropriately
2149 rigorous security practices to be used.
2151 Even with the most rigorous security practices, a CA may be
2152 compromised. If this compromise is detected quickly, relying parties
2153 can remove the CA from their list of trusted CAs, and other CAs can
2154 revoke any certificates issued to the CA. However, CA compromise may
2155 go undetected for some time, and there's always the possibility that
2156 a CA is being operated improperly or in a manner that is not in the
2157 interests of the relying parties. For this reason, relying parties
2158 may wish to "pin" a small number of particularly critical
2159 certificates (such as the certificate for the XMPP-Grid Controller).
2160 Once a certificate has been pinned, the relying party will not accept
2161 another certificate in its place unless the Administrator explicitly
2162 commands it to do so. This does not mean that the relying party will
2163 not check the revocation status of pinned certificates. However, the
2164 Administrator may still be consulted if a pinned certificate is
2165 revoked, since the CA and revocation process are not completely
2166 trusted.
2168 6.4. Summary
2170 XMPP-Grid's considerable value as a broker for security-sensitive
2171 data exchange distribution also makes the protocol and the network
2172 security elements that implement it a target for attack. Therefore,
2173 strong security has been included as a basic design principle within
2174 the XMPP-Grid design process.
2176 The XMPP-Grid transport protocol provides strong protection against a
2177 variety of different attacks. In the event that a XMPP-Grid Node or
2178 XMPP-Grid Controller is compromised, the effects of this compromise
2179 have been reduced and limited with the recommended role-based
2180 authorization model and other provisions, and best practices for
2181 managing and protecting XMPP-Grid systems have been described. Taken
2182 together, these measures should provide protection commensurate with
2183 the threat to XMPP-Grid systems, thus ensuring that they fulfill
2184 their promise as a network security clearing-house.
2186 7. Privacy Considerations
2188 XMPP-Grid Nodes may publish information about endpoint health,
2189 network access, events (which may include information about what
2190 services an endpoint is accessing), roles and capabilities, and the
2191 identity of the end user operating the endpoint. Any of this
2192 published information may be queried by other XMPP-Grid Nodes and
2193 could potentially be used to correlate network activity to a
2194 particular end user.
2196 Dynamic and static information brokered by a XMPP-Grid Controller,
2197 ostensibly for purposes of correlation by XMPP-Grid Nodes for
2198 intrusion detection, could be misused by a broader set of XMPP-Grid
2199 Nodes which hitherto have been performing specific roles with strict
2200 well-defined separation of duties.
2202 Care should be taken by deployers of XMPP-Grid to ensure that the
2203 information published by XMPP-Grid Nodes does not violate agreements
2204 with end users or local and regional laws and regulations. This can
2205 be accomplished either by configuring XMPP-Grid Nodes to not publish
2206 certain information or by restricting access to sensitive data to
2207 trusted XMPP-Grid Nodes. That is, the easiest means to ensure
2208 privacy or protect sensitive data, is to omit or not share it at all.
2210 Another consideration for deployers is to enable end-to-end
2211 encryption to ensure the data is protected from the data layer to
2212 data layer and thus protect it from the transport layer.
2214 8. Evolution of XMPP-Grid
2216 XMPP-Grid is the convergence of IF-MAP from the Trusted Computing
2217 Group and the Platform-Exchange Grid (pxGrid) from Cisco Systems.
2218 Both frameworks focus on enabling end users to implement multi-vendor
2219 systems that share security context information that enables
2220 coordinated defense-in-depth and security automation.
2222 An ecosystem of vendors has been shipping IF-MAP enabled products
2223 since 2008 to provide an architecture that supports standardized,
2224 dynamic security data interexchange among a wide variety of
2225 networking and security components. IF-MAP has been continually
2226 enhanced by the Trusted Computing Group, culminating in the most
2227 recent version, IF-MAP 2.2, published in March 2014. IF-MAP has
2228 focused on providing a standardized information model that can be
2229 utilized for data interoperability between vendors.
2231 Cisco pxGrid was introduced in 2013 and has since developed a broad-
2232 based security and networking vendor ecosystem. pxGrid was developed
2233 by extending standards-based XMPP message routing. The goal of
2234 pxGrid is to specifically address a lack of transport protocols
2235 available in the industry that deliver highly scalable, many-to-many
2236 platform security data interexchange in real-time.
2238 XMPP-Grid brings together the strengths of both IF-MAP and pxGrid.
2239 IF-MAP provides a mature and standardized information model. This
2240 information model is accessible by Cisco pxGrid to transport relevant
2241 data between systems. The combined XMPP-Grid delivers a highly
2242 scalable, real-time data exchange transport protocol with an
2243 interoperable information model based on the experience from real-
2244 world, production deployments.
2246 9. Acknowledgements
2248 The authors would like to acknowledge the contributions, authoring
2249 and/or editing of the following people: Henk Birkholz, Jessica
2250 Fitzgerald-McKay, Steve Hanna, Steve Venema.
2252 10. References
2254 10.1. Normative References
2256 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
2257 Requirement Levels", BCP 14, RFC 2119, March 1997.
2259 [RFC3922] Saint-Andre, P., "Mapping the Extensible Messaging and
2260 Presence Protocol (XMPP) to Common Presence and Instant
2261 Messaging (CPIM)", RFC 3922, October 2004.
2263 [RFC3923] Saint-Andre, P., "End-to-End Signing and Object Encryption
2264 for the Extensible Messaging and Presence Protocol
2265 (XMPP)", RFC 3923, October 2004.
2267 [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and
2268 Security Layer (SASL)", RFC 4422, June 2006.
2270 [RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
2271 Protocol (XMPP): Core", RFC 6120, March 2011.
2273 [RFC6121] Saint-Andre, P., "Extensible Messaging and Presence
2274 Protocol (XMPP): Instant Messaging and Presence", RFC
2275 6121, March 2011.
2277 10.2. Informative References
2279 [I-D.ietf-sacm-terminology]
2280 Waltermire, D., Montville, A., Harrington, D., Cam-Winget,
2281 N., Lu, J., Ford, B., and M. Kaeo, "Terminology for
2282 Security Assessment", draft-ietf-sacm-terminology-06 (work
2283 in progress), February 2015.
2285 [I-D.ietf-sacm-use-cases]
2286 Waltermire, D. and D. Harrington, "Endpoint Security
2287 Posture Assessment - Enterprise Use Cases", draft-ietf-
2288 sacm-use-cases-09 (work in progress), March 2015.
2290 [I-D.ietf-uta-tls-bcp]
2291 Sheffer, Y., Holz, R., and P. Saint-Andre,
2292 "Recommendations for Secure Use of TLS and DTLS", draft-
2293 ietf-uta-tls-bcp-11 (work in progress), February 2015.
2295 [IF-MAP] Trusted Computing Group, "TNC Architecture for
2296 Interoperability, Revision 1.5", May 2012.
2298 [IF-MAP-ICS]
2299 Trusted Computing Group, "TNC IF-MAP Metadata for ICS,
2300 Security, Revision 1.0", October 2012.
2302 [IF-MAP-NETSEC]
2303 Trusted Computing Group, "TNC IF-MAP Metadata for Network
2304 Security, Revision 1.0", August 2010.
2306 [IF-MAP-SOAP]
2307 Trusted Computing Group, "TNC IF-MAP Binding for SOAP,
2308 Revision 2.1", May 2012.
2310 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
2312 [RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident
2313 Object Description Exchange Format", RFC 5070, December
2314 2007.
2316 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
2317 (TLS) Protocol Version 1.2", RFC 5246, August 2008.
2319 Authors' Addresses
2321 Joseph Salowey
2322 Tableau Software
2323 837 North 34th Street, Suite 200
2324 Seattle , WA 98103
2326 Email: joe@salowey.net
2328 Lisa Lorenzin
2329 Pulse Secure
2330 2700 Zanker Rd., Suite 200
2331 San Jose, CA 95134
2332 USA
2334 Email: llorenzin@pulsesecure.net
2336 Cliff Kahn
2337 Pulse Secure
2338 2700 Zanker Rd., Suite 200
2339 San Jose, CA 95134
2340 USA
2342 Email: cliffordk@pulsesecure.net
2344 Scott Pope
2345 Cisco Systems
2346 5400 Meadows Road
2347 Suite 300
2348 Lake Oswego, OR 97035
2349 USA
2351 Email: scottp@cisco.com
2352 Syam Appala
2353 Cisco Systems
2354 80 West Tasman Drive
2355 San Jose, CA 95134
2356 USA
2358 Email: syam1@cisco.com
2360 Aaron Woland
2361 Cisco Systems
2362 1900 South Boulevard
2363 Charlotte, NC 28203
2364 USA
2366 Email: aawoland@cisco.com
2368 Nancy Cam-Winget (editor)
2369 Cisco Systems
2370 3550 Cisco WAY
2371 San Jose, CA 95134
2372 USA
2374 Email: ncamwing@cisco.com