SACM N. Cam-Winget, Ed.
Internet-Draft B. Ford
Intended status: Informational Cisco Systems
Expires: May 23, 2015 L. Lorenzin
Pulse Secure
I. McDonald
High North Inc
A. Woland
Cisco Systems
November 19, 2014

Secure Automation and Continuous Monitoring (SACM) Architecture


This document describes an architecture for standardization of interfaces, protocols and information models related to security automation and continuous monitoring. It describes the basic architecture, components and their interfaces defined to enable the collection, acquisition and verification of Posture and Posture Assessments.

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Table of Contents

1. Introduction

Several data models and protocols are in use today that allow different applications to perform the collection, acquisition, and assessment of posture. These applications can vary from being focused on general system and security management to specialized configuration, compliance, and control systems. With an existing varied set of applications, there is a strong desire to standardize data models, protocols, and interfaces to better allow for the automation of such data processes.

This document addresses general and architectural requirements defined in [I-D.ietf-sacm-requirements]. This document describes an architecture to enable standardized collection, acquisition, and verification of Posture and Posture Assessments. This architecture includes the components and interfaces that can be used to better identify the Information Model and type(s) of transport protocols needed for communication.

This document uses terminology defined in [I-D.ietf-sacm-terminology].

2. Problem Statement

Securing information and the systems that store, process, and transmit that information is a challenging task for organizations of all sizes, and many security practitioners spend much of their time on manual processes. Administrators can't get technology from disparate sources to work together; they need information to make decisions, but the information is not available. Everyone is collecting the same data, but storing it as different information. Administrators therefore need to collect data and craft their own information, which may not be accurate or interoperable because it's customized by each administrator, not shared.

Security automation and continuous monitoring require a large and broad set of mission and business processes; to make the most effective of use of technology, the same data must support multiple processes. The need for complex characterization and assessment necessitates components and functions that interoperate and can build off each other to enable far-ranging and/or deep-diving analysis.

3. Architectural Overview

At a high level, the architecture describes 'How' and 'Where' information and assessment of posture may be collected, processed or assessed. Three main functional components are defined: a Posture Assessment Information Consumer (C), a Posture Assessment Information Provider (P), and a Controller (Cr) used to facilitate some of the security functions such as authentication and authorization and other metadata functions.

                       | +--------------------------------------+
                       | | +--------------------------------------+
                       | | |                                      |
                       +-| |      Posture Assessment              |
                         +-|      Information Consumer (C)        |
                             /   \         /   \            /   \
                            /     \       /     \          /     \
                            -     -       -  d  -          -     -
                             || ||A        | a  |B          |   |C
                             || ||         | t  |           |   |
                            -     -       -  a  -           |   |
                            \     /       \     /           |   |
                             \   /         \   /            |   |
                          /|---------------------|\         |   |  
                   /|----/                         \--------| d |--|\ 
                  /     /      Controller (Cr)      \ ctrl  | a |    \  
                  \     \ [Broker/Proxy/Repository] / plane | t |    /
                   \|----\                         /--------| a |--|/ 
                          \|---------------------|/         |   |
                             /   \         /   \            |   | 
                            /     \       /     \           |   | 
                            -     -       -  d  -           |   | 
                             || ||A        | a |B           |   |C
                             || ||         | t |            |   |
                            -     -       -  a  -          -     -
                            \     /       \     /          \     /
                             \   /         \   /            \   /
                           |                                    |-+
                           |     Posture Assessment             | |
                           |    Information Provider (P)        | |-+
                           +------------------------------------+ | |
                             +------------------------------------+ |


Figure 1: Simple Architectural Model

3.1. Component Roles

An endpoint, as defined in [I-D.ietf-sacm-terminology], can function in two primary ways: as the target of an assessment, and/or as a functional component of the SACM architecture that can instantiate one or more capabilities (see Section 4). Individual endpoints may be a target endpoint, or a component, or both simultaneously. Components can take on the role of Posture Assessment Information Provider, Posture Assessment Information Consumer, and/or Controller.

3.1.1. Posture Assessment Information Provider

The Posture Assessment Information Provider (P or Provider) is the component that contributes Posture Assessment Information and/or Guidance either spontaneously or in response to a request. A Provider can be a Posture Evaluator, Posture Collector, or an application that has aggregated Posture Assessment Information that can be shared.

The Provider implements the capabilities and functions that must be handled to share or provide Posture Assessment information.

A Provider may provide information spontaneously, or in response to a direct request from a Consumer. The information may be filtered or truncated to provide a subset of the requested information to honor the request. This truncation may be performed based on the Consumer's request and/or the Provider's ability to filter. The latter case may be due to security considerations (e.g. authorization restrictions due to domain segregation, privacy, etc.).

The Provider may only be able to share the Posture Assessment Information using a specific data model and protocol. It may use a standard data model and/or protocol, a non-standard data model and/or protocol, or any combination of standard and non-standard data models and protocols. It may also choose to advertise its capabilities through a metadata abstraction or through the use of the registration function of the Controller (see Section 3.1.3) [QUESTION: Are these different?].

The Provider must be authorized to provide the Posture Assessment Information and further, be authorized to do so with the specific data models and protocols.

3.1.2. Posture Assessment Information Consumer

As described in Section 2.2 of the SACM Use Cases [I-D.ietf-sacm-use-cases], several usage scenarios are posed with different application types requesting posture assessment information. Whether it is a configuration verification system; a checklist verification system; or a system for detecting posture deviations, compliance or vulnerabilities, they all need to acquire information about Posture Assessment. Thus, the architectural component to enable such requests is defined as a Posture Assessment Information Consumer (C or Consumer).

The Consumer implements the capabilities and functions that must be handled in order to facilitate a Posture Assessment Information Request. Requests can be either for a single posture attribute or a set of posture attributes where those attributes can be the raw information or an evaluated or assessed state based upon that information. The Consumer may further choose to query for the information directly (one-time query), or to request for updates to be provided as the Posture Assessment Information changes (subscription). A request could be made directly to an explicitly identified Posture Assessment Information Provider (P or Provider), but a Consumer may also desire to obtain the information without having to know the available providers.

There may be instances where a Consumer may be requesting information from various Providers and due to its policy or application requirements may need to be better informed of the Providers and their capabilities. In those use cases, a Consumer may also request to discover the respective capabilities of those Providers using the discovery function of the Controller (see Section 3.1.3).

The Controller (described below) must authorize a Consumer to acquire the information it is requesting. The Consumer may also be subject to limits or constraints on the numbers, types, sizes, and rate of requests.

3.1.3. Controller

The Controller (Cr) may be an independent endpoint, or an abstracted component running on an endpoint has multiple capabilities. The purpose of the Controller is to execute on security functions and overall system functions including:

The architecture must account for an abstraction where a Controller may be defined to affect the authentication of Consumers and Providers independent of the actual information sharing communication channel. This supports use cases where:
  • Consumers may request information independent of knowing the identities of the Providers.
  • Providers may want to share the information without prior solicitation.

To restrict how Posture Assessment Information is shared between the Consumers and Providers. At minimum a management function must define the necessary policies.
The introduction of the Controller supports use cases where:
  • Consumer's may request information independent of knowing the identities of the Provider's
  • Providers may want to share information unsolicited
The architecture must account for an abstraction where a Controller may be defined to affect the authentication of the Consumers and Providers independent of the actual information sharing communication channel.
Identity Management:
As typically, Identity Management for authentication and authorization policies are best defined through a centralized component, the Controller also provides these services.
A discovery mechanism is required to facilitate the interaction of Providers that may have different Posture Assessment Information and potentially limited (or a rich set) of ways in which they can share the information. Through the use of a discovery mechanism, Consumers can have visibility of the Providers present and the type(s) of Posture Assessment Information that is available and how it can be requested. Similarly, a Provider may need to register what Posture Assessment Information it can share and how it can share it (e.g. protocol or with filtering capabilities). Enabling this function through a Controller also allows for the distinct definition of security considerations (e.g. authorized registration of capabilities and of Providers) beyond how a Provider may define its own capability.

These functions may be provided by a single component, or by multiple components. For example, an endpoint acting as a data store may also act as its own broker.

The Controller also helps define how to manage an overall SACM system that allows for Consumers to obtain the desired Posture Assessment Information without the need to distinctly know and establish a one (Consumer) to many (Provider) connections. Note that the Controller also allows for the direct discovery and connection between a Consumer and Provider.

3.2. Interfaces between Consumers, Providers, and Controllers

As shown in Figure 1, communication can proceed with the following interfaces and expected functions and behaviors:

interface "A" shown in Figure 1 handles the management and control functions that are needed to establish, at minimum, a secure communication between Consumers and Providers. The interface must also handle the functions to allow for the discovery and registration of the Providers as well as the ways in which Posture Assessment Information can be provided (or requested).
interface "B" shown in Figure 1 enables Providers to share their Posture Assessment Information spontaneously; similarly, it enables Consumers to request information without having to know the identities (or reachability) of all the Providers that can fulfill Consumers' requests.
interface "C" shown in Figure 1 demonstrates the ability and desire for Consumers and Providers to be able to communicate directly when a Provider is sharing Posture Assessment Information directly to a Consumer. The interface allows for the different data models and protocols to be used between a Consumer and a Provider with the expectation that the appropriate authentication and authorization mechanisms have been employed to establish a secure communication link between the Consumer and the Provider. Typically, it is expected that the secure link establishment occurs as a management or control function through the abstracted Controller role (e.g. the Controller could be a proxy or could be embedded in a Consumer or a Provider).

TODO - add text around the usage of various protocols for endpoint data collection (SNMP, NETCONF, etc.?)

4. Component Capabilities

TODO: Intro text about capabilities

4.1. Control Plane Capabilities

TODO: Intro text about control plane capabilities

TODO: Determine whether broker, proxy, and repository need to be full subsections or paragraphs in this section.

Intermediary negotiating connection between provider and consumer.
Intermediary negotiating on behalf of a consumer.
Intermediary receiving and storing data from a provider, and providing stored data to a consumer.

4.2. Data Plane Capabilities

TODO: Intro text about data plane capabilities

4.2.1. Collector

A collector consumes Guidance and/or other Posture Assessment Information; it provides Posture Assessment Information. Collectors may be internal or external. Internal Collector

TODO External Collector

An external collector is a collector that observes endpoints from outside. These collectors may be configured and operated to manage assets for reasons including, but not limited to, posture assessment. Collectors that are not primarily intended to support posture assessment (e.g. intrusion detection systems) may still provide information that speaks to endpoint posture (e.g. behavioral information).

Examples: Collector Interactions With Target Endpoints


4.2.2. Evaluator

An evaluator consumes Posture Assessment Information, Evaluation Results, and/or Guidance; it provides Evaluation Results. An evaluator may consume endpoint attribute assertions, previous evaluations of posture attributes, or previous reports of Evaluation Results.

[kkw-i don't think this conflicts with the definition in the terminology doc re: that evaluation tasks evaluate posture attributes.]

[cek-I like the change. I think it *does* require a change in the terminology doc, though.]

Example: a NEA posture validator [RFC5209]

[jmf- a NEA posture validator is not an example of this definition. A NEA posture assessment is, maybe?]

[cek-Why isn't a NEA posture validator an example?]

4.2.3. Report Generator

A report generator consumes Posture Assessment Information, Evaluation Results, and/or Guidance; it provides reports. These reports are based on:

It may summarize data continually, as the data arrives. It also may summarize data in response to an ad hoc query.

4.2.4. Data Store

A data store consumes any data; it provides any data.

5. Example Illustration of Capabilities and Workflow

TODO: revise all this text

                        | +-------------------------------+
                        | |                               |
                        +-|        Controller (Cr)        |
                             //   /            \   \\
                            //   /              \   \\
                         A //   /                \   \\ A
                          //   /                  \   \\                            
                         //   /  B             B   \   \\
                        //   /                      \   \\
 +-------------------------------+             +-------------------------------+
 | +-------------------------------+     A     | +-------------------------------+
 | |                               |===========| |                               |
 | |   Posture Assessment          |-----------| |   Posture Assessment          |
 +-|   Information Consumer (C)    |     C     +-|   Information Provider (P)    |
    +-------------------------------+             +-------------------------------+

Figure 2: Communications Model

SACM's focus is on the automation of collection, verification and update of system security configurations pertaining to endpoint assessment. In order to carry out these tasks, the architectural components shown in Figure 1 can be further refined as:

Posture Assessment Information Providers:
a Provider may be dedicated to perform either the collection, aggregation or evaluation of one or more posture attributes whose results can be conveyed to a Posture Assessment Information Consumer. In this example form of the SACM architecture model, these are shown as Collection, Evaluation, and Results Providers. Note that there may be posture attributes or posture assessment information that articulates Guidance information which may or may not be present in the architecture.
Posture Assessment Information Consumers:
a Consumer may request or receive one or more posture attributes or posture assessment information from a Posture Assessment Information Provider for their own use. In this example form of the SACM architecture model, these are shown as Collection, Evaluation, and Results Consumers. Note that there may be posture attributes or posture assessment information articulating Guidance information which may or may not be present in the architecture to be provided or consumed.
Data Stores:
a Data Store is both a Provider and a Consumer, storing one or more posture attributes or assessments for endpoints. It should be understood that these repositories interface directly to a Provider or Consumer (and Guidance) but the interfaces used to interact between them is outside the scope of SACM (e.g. no interface arrows are shown in the architecture).

Figure 3 illustrates an example flow for how Posture Assessment Information may flow.

				 |Evaluation   |
		+-------------+  |Guidance     +--+
		|Endpoint     |  |Capability   |  |
	+-------+             |  +-------------+  |
	|       |             |                   |
	|       +-------+-----+             +-----v-------+
	| Collection    |                   |Evaluation   |
      +-> Capability +--+--------+          |Capability   |
      | |            |Collection |    +-----------+   +----------+
      | +------------+Provider   |    |           |---|          |
      |              |           |    |Collection |   |Evaluation|
      |              |           |    |Consumer   |   |Provider  |
      |              +----+------+    +----^------+   +---+------+
     ++---------+         |                |              |
     |Collection|   +-----v------+     +---+--------+     |
     |Guidance  |   |            |     |Collection  |     |
     |Capability|   |Collection  |     |Provider    |     |
     |          |   |Consumer    |-----|            |     |
     +----------+   +------------+     +------------+     |
			       | Collection |             |
			       | Data Store |             |
			       +------------+             |
	 +--------------+           +---------------+     |
	 |Evaluation    |           |Evaluation     |     |
	 |Results       |           |Consumer       <-----+
	 |Provider      |-----------|               |
	 +-----+--------+           +---------------+
	       |     |Results Reporting|
	       |     |Capability       |
	       |     +------------^----+
	       |                  |
	 +-----v--------+    +----+------+
	 |Evaluation    |    |Reporting  |
	 |Results       |    |Guidance   |
	 |Consumer      |    |Data Store |
	 +---+----------+    +-----------+ +-------------+
	     |                             | Results     |
	     +-----------------------------> Data Store  |
					   |             |

Figure 3: Example Posture Information Flow

TODO - add example of / more content around interactions with endpoint, possible communications patterns

6. Acknowledgements

The authors would like to thank Jim Bieda, Henk Birkholz, Jessica Fitzgerald-McKay, Trevor Freeman, Adam Montville, and David Waltermire for participating in architecture design discussions, reviewing, and contributing to this draft.

7. IANA Considerations

This memo includes no request to IANA.

8. Security Considerations

TBD. This section will need to cover the AAA and confidentiality/integrity of the data and data transports to be considered. Also, the considerations for the interfaces (which may be covered in transports) between the Consumers, Providers, and the Controller.

9. References

9.1. Normative References

[I-D.ietf-sacm-requirements] Cam-Winget, N. and L. Lorenzin, "Secure Automation and Continuous Monitoring (SACM) Requirements", Internet-Draft draft-ietf-sacm-requirements-02, October 2014.
[I-D.ietf-sacm-terminology] Waltermire, D., Montville, A., Harrington, D. and N. Cam-Winget, "Terminology for Security Assessment", Internet-Draft draft-ietf-sacm-terminology-04, May 2014.
[I-D.ietf-sacm-use-cases] Waltermire, D. and D. Harrington, "Endpoint Security Posture Assessment - Enterprise Use Cases", Internet-Draft draft-ietf-sacm-use-cases-03, October 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

9.2. Informative References

[RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between Information Models and Data Models", RFC 3444, January 2003.
[RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K. and J. Tardo, "Network Endpoint Assessment (NEA): Overview and Requirements", RFC 5209, June 2008.

Authors' Addresses

Nancy Cam-Winget (editor) Cisco Systems 3550 Cisco Way San Jose, CA 95134 US EMail:
Brian Ford Cisco Systems 5507-10 Nesconset Hwy #242 Mt Sinai, NY 11766 US EMail:
Lisa Lorenzin Pulse Secure 2700 Zanker Rd, Suite 200 San Jose, CA 95134 US EMail:
Ira E McDonald High North Inc PO Box 221 Grand Marais, MI 49839 US EMail:
Aaron Woland Cisco Systems 1900 South Blvd. Suite 200 Charlotte, NC 28203 US EMail: