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SACM                                                  N. Cam-Winget, Ed.
Internet-Draft                                             Cisco Systems
Intended status: Informational                               L. Lorenzin
Expires: September 10, 2015                                 Pulse Secure
                                                             I. McDonald
                                                          High North Inc
                                                               A. Woland
                                                           Cisco Systems
                                                           March 9, 2015


    Secure Automation and Continuous Monitoring (SACM) Architecture
                    draft-ietf-sacm-architecture-03

Abstract

   This document defines a reference 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.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 10, 2015.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Architectural Overview  . . . . . . . . . . . . . . . . . . .   3
     3.1.  Component Roles . . . . . . . . . . . . . . . . . . . . .   4
       3.1.1.  Posture Assessment Information Provider . . . . . . .   5
       3.1.2.  Posture Assessment Information Consumer . . . . . . .   5
       3.1.3.  Controller  . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Interfaces between Consumers, Providers, and Controllers    8
   4.  Component Capabilities  . . . . . . . . . . . . . . . . . . .   9
     4.1.  Control Plane Capabilities  . . . . . . . . . . . . . . .   9
     4.2.  Data Plane Capabilities . . . . . . . . . . . . . . . . .  10
       4.2.1.  Collector . . . . . . . . . . . . . . . . . . . . . .  10
         4.2.1.1.  Internal Collector  . . . . . . . . . . . . . . .  10
         4.2.1.2.  External Collector  . . . . . . . . . . . . . . .  10
         4.2.1.3.  Collector Interactions With Target Endpoints  . .  11
       4.2.2.  Evaluator . . . . . . . . . . . . . . . . . . . . . .  11
       4.2.3.  Report Generator  . . . . . . . . . . . . . . . . . .  11
       4.2.4.  Data Store  . . . . . . . . . . . . . . . . . . . . .  12
   5.  Example Illustration of Capabilities and Workflow . . . . . .  12
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  16
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  16
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

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.





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   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,
   assessed, exchanged, and/or stored.  Three main functional components
   are defined: a Posture Assessment Information Consumer (Cs), 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.











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                         +--------------------------------------+
                         | +--------------------------------------+
                         | | +--------------------------------------+
                         | | |                                      |
                         +-| |      Posture Assessment              |
                           +-|      Information Consumer (Cs)       |
                             +--------------------------------------+
                               /   \         /   \            /   \
                              /     \       /     \          /     \
                              -     -       -  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).  In the SACM architecture,



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   individual endpoints may be a target endpoint, or a component, or
   both simultaneously.  An endpoint acting as a component may perform
   one or more roles.  Components can take on the role(s) 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, Data Store
   (see Section 4.2), 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 within the data model itself, or
   through the use of the registration function of the Controller (see
   Section 3.1.3).

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

3.1.2.  Posture Assessment Information Consumer

   The Posture Assessment Information Consumer (C or Consumer) is the
   component that requests or accepts Posture Assessment Information
   and/or Guidance.  A Consumer can be a Posture Evaluator, Report
   Generator, Data Store (see Section 4.2), or an application that
   consumes Posture Assessment Information in order to perform another
   function.




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   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.  The architectural component
   performing such requests is a 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; 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 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) or may
   request metadata reflecting the capabilities of the Providers.

   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 or Controller) is a component defined to
   facilitate information sharing and to execute on security functions
   and overall SACM management and control system functions including:

   Authentication:  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.





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    *  Providers may want to share the information without prior
       solicitation.

    The architecture must account for an abstraction where a Controller
    may be defined to effect the authentication of the Consumers and
    Providers independent of the actual information-sharing
    communication channel.

   Authorization:  The restriction of Posture Assessment Information
    sharing between the Consumers and Providers.  At minimum, a
    management function must define the necessary policies.

   Identity Management:  Since Identity Management for authentication
    and authorization policies is best performed via a centralized
    component, the Controller also facilitates this function.

    The Controller needs to be able to identify the endpoints
    participating as SACM components and the roles that they play.
    Similar to how access control may be effected via Authentication,
    Authorization, and Accounting Systems (e.g.  AAA services), the same
    principle is defined; as AAA services depend on Identity Management
    services, the Controller will need a similar function and interface
    to Identity Management services.

   Registration/Discovery:  The discovery of what Providers are
    available, what information a Provider can share, and how it can be
    requested / communicated.  A discovery mechanism is required to
    facilitate interaction with 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 into the Providers present, the type(s) of Posture
    Assessment Information available, and how it can be requested.
    Similarly, a Provider may need to publish what Posture Assessment
    Information it can share and how it can share it (e.g. protocol,
    filtering capabilities, etc.).  Enabling this function through a
    Controller or through metadata publication also allows for the
    distinct definition of security considerations (e.g. authorized
    registration / publication of capabilities by Providers) beyond how
    a Provider may define its own capability.

   Beyond the control and management functions for the SACM system, a
   Controller may also provide proxy or broker or repository (and
   possibly routing) capabilities in the data plane (see Section 4.1).
   In the deployment scenario where Providers do not assert the need to
   know their Consumers and/or vice versa, the Controller can thus
   provide the appropriate functions to ensure the Posture Assessment



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   Information is appropriately communicated from the Providers to the
   authorized Consumers.

   The Controller, acting as a management control plane, 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 one (Consumer) to many (Provider)
   connections.  Similarly, a Provider may not need to distinctly know
   and establish one (Provider) to many (Consumer) connections; e.g. the
   Controller enables the means to allow a SACM system to support many
   to many connections.  Note that the Controller also allows for the
   direct discovery and connection between a Consumer and Provider.

   As a SACM component, the Controller may be instantiated within a
   system or device acting as a Provider or a Consumer (or both), or as
   its own distinct Controller entity.  In a rich SACM environment, it
   is feasible to instantiate a Controller that provides both the
   management (and control) functions for SACM as well as provide the
   proxying, brokering, and/or repository capabilities for the actual
   data, e.g.  Posture Assessment Information flow.  Note that
   Controllers may be implemented to only provide the management and
   control functions or only the data flow capabilities or both.

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:

   A:  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).

   B:  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.

   C:  interface "C" shown in Figure 1 illustrates 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



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    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 broker or could be
    embedded in a Consumer or a Provider).

   A variety of protocols, such as SNMP, NETCONF, NEA protocols
   [RFC5209], and other similar interfaces, may be used for collection
   of data from the target endpoints by the Posture Information
   Provider.  Those interfaces are outside the scope of SACM.

4.  Component Capabilities

   SACM components offer a variety of capabilities which may be
   instantiated on a single endpoint or on separate standalone endpoints
   providing various roles.

4.1.  Control Plane Capabilities

   Control plane capabilities represent various services offered by the
   Controller to the Providers and Consumers to facilitate sharing of
   information.  A Controller may have Broker, Proxy, or Repository
   capabilities, or any combination thereof.

   Broker:  Intermediary negotiating connection between Provider and
    Consumer.  A Controller acting as a Broker:

    *  Receives a request for information from a Consumer and instructs
       the Consumer where and how retrieve the requested information.

    *  Receives a publication request from a Provider and instructs the
       Provider where and how to deliver the published information.

    The information itself is neither distributed nor stored by the
    Controller.

   Proxy:  Intermediary negotiating on behalf of a Consumer or Provider.
    A Controller acting as a Proxy:

    *  Receives a request for information from a Consumer, retrieves the
       information from the appropriate Providers, and provides the
       information to the Consumer.

    *  Receives a publication request from a Provider, accepts the
       published information, and distributes it to appropriate
       consumers.





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    The information itself is distributed by, but not stored by, the
    Controller.

   Repository:  Intermediary receiving and storing data from a Provider,
    and providing stored data to a Consumer.  A Controller acting as a
    Repository:

    *  Receives a request for information from a Consumer, retrieves the
       information from its data stores, and provides the information to
       the Consumer.

    *  Receives a publication request from a provider, stores the
       published information, and distributes it to appropriate
       Consumers.

    The information itself is both handled by and stored by the
    Controller.

4.2.  Data Plane Capabilities

   Data plane capabilities represent the ability of a Provider or
   Consumer to perform a SACM-related task.  For example, the Collector
   capability indicates that a Provider can perform Collection tasks;
   the Evaluator capability indicates that a Consumer can perform
   Evaluation tasks.

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.

4.2.1.1.  Internal Collector

   An internal collector is a collector that runs on the endpoint and
   collects posture information locally.

4.2.1.2.  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:



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   o  A RADIUS server, which collects information about which endpoints
      have logged onto the network

   o  A network profiling system, which collects information by
      discovering and classifying network nodes

   o  A Network Intrusion Detection System (NIDS) sensor, which collects
      information about endpoint behavior by observing network traffic

   o  A vulnerability scanner, which collects information about endpoint
      configuration by scanning endpoints

   o  A hypervisor, which collects information about endpoints running
      as virtual guests in its host environment

   o  A management system that configures and installs software on the
      endpoint, which collects information based on its provisioning
      activities

4.2.1.3.  Collector Interactions With Target Endpoints

   TODO - examples of endpoint interactions with local internal
   collector (e.g.  NEA client), endpoint with remote internal collector
   (SNMP query), and external collector (sensor)

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.

   TODO: update the terminology doc to reflect this definition

   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:




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   o  Endpoint Attribute Assertions, including Evaluation Results

   o  Other Reports (e.g., a weekly report may be created from daily
      reports)

   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: once the group reaches consensus on content for the previous
   sections, revise all this text based upon the agreed-upon
   architecture


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


                      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



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    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.


























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                                   +-------------+
                                    |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




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   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

   The SACM architecture defines three main components that interface
   with each other both for management and control (in the control
   plane) and for the sharing of Posture Assessment Information.
   Considerations for transitivity of trust between a Provider and
   Consumer can be made if there is a well understood trust between the
   Provider and the Controller and between the Consumer and Controller.
   The trust must include strong mutual authentication, at minimum,
   between the Provider and Controller and between the Consumer and
   Controller.

   To address potential Man-in-the-Middle (MitM) attacks, it is also
   strongly recommended that the communications be secured to include
   replay protection and message integrity (e.g. transport integrity and
   if required, data integrity).  Similarly, to avoid potential message
   tampering, confidentiality should also be provided.

   As the Controller provides the security functions for the SACM
   system, the Controller should provide strong authorizations based on
   either or both business and regulatory policies to ensure that only
   authorized Consumers and obtaining Posture Assessment Information
   from authorized Providers.  It is presumed that once authenticated
   and authorized, the Provider, Controller or Consumer is deemed
   trustworthy; though note that it is possible that the modules or
   devices hosting the SACM components may be compromised as well (e.g.
   due to malware or tampering); however, addressing that level of
   trustworthiness is out of scope for SACM.

   As the data models defined through the interfaces are transport
   agnostic, the Posture Assessment Information data in the interfaces
   may leverage the transport security properties as the interfaces are
   transported between the Provider, Consumer and Controller.  However,
   there may be other devices, modules or components in the path between



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   the Provider, Consumer and Controller that may observe the interfaces
   flowing through them.

9.  References

9.1.  Normative References

   [I-D.ietf-sacm-requirements]
              Cam-Winget, N. and L. Lorenzin, "Secure Automation and
              Continuous Monitoring (SACM) Requirements", draft-ietf-
              sacm-requirements-03 (work in progress), January 2015.

   [I-D.ietf-sacm-terminology]
              Waltermire, D., Montville, A., Harrington, D., Cam-Winget,
              N., Lu, J., Ford, B., and M. Kaeo, "Terminology for
              Security Assessment", draft-ietf-sacm-terminology-06 (work
              in progress), February 2015.

   [I-D.ietf-sacm-use-cases]
              Waltermire, D. and D. Harrington, "Endpoint Security
              Posture Assessment - Enterprise Use Cases", draft-ietf-
              sacm-use-cases-08 (work in progress), February 2015.

   [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: ncamwing@cisco.com






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   Lisa Lorenzin
   Pulse Secure
   2700 Zanker Rd, Suite 200
   San Jose, CA  95134
   US

   Email: llorenzin@pulsesecure.net


   Ira E McDonald
   High North Inc
   PO Box 221
   Grand Marais, MI  49839
   US

   Email: blueroofmusic@gmail.com


   Aaron Woland
   Cisco Systems
   1900 South Blvd. Suite 200
   Charlotte, NC  28203
   US

   Email: loxx@cisco.com


























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