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Versions: (draft-mandm-sacm-architecture) 00 01 02 03 04 06

SACM Working Group                                          A. Montville
Internet-Draft                                                 B. Munyan
Intended status: Standards Track                                     CIS
Expires: 12 November 2020                                    11 May 2020


   Security Automation and Continuous Monitoring (SACM) Architecture
                        draft-ietf-sacm-arch-06

Abstract

   This document defines an architecture enabling a cooperative Security
   Automation and Continuous Monitoring (SACM) ecosystem.  This work is
   predicated upon information gleaned from SACM Use Cases and
   Requirements ([RFC7632] and [RFC8248] respectively), and terminology
   as found in [I-D.ietf-sacm-terminology].

   WORKING GROUP: The source for this draft is maintained in GitHub.
   Suggested changes should be submitted as pull requests at
   https://github.com/sacmwg/ietf-mandm-sacm-arch/.  Instructions are on
   that page as well.

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 https://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 12 November 2020.

Copyright Notice

   Copyright (c) 2020 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 (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   4
   2.  Terms and Definitions . . . . . . . . . . . . . . . . . . . .   4
   3.  Architectural Overview  . . . . . . . . . . . . . . . . . . .   4
     3.1.  SACM Role-based Architecture  . . . . . . . . . . . . . .   5
     3.2.  Architectural Roles/Components  . . . . . . . . . . . . .   5
       3.2.1.  Orchestrator(s) . . . . . . . . . . . . . . . . . . .   6
       3.2.2.  Repositories/CMDBs  . . . . . . . . . . . . . . . . .   6
       3.2.3.  Integration Service . . . . . . . . . . . . . . . . .   6
     3.3.  Downstream Uses . . . . . . . . . . . . . . . . . . . . .   7
       3.3.1.  Reporting . . . . . . . . . . . . . . . . . . . . . .   7
       3.3.2.  Analytics . . . . . . . . . . . . . . . . . . . . . .   7
     3.4.  Sub-Architectures . . . . . . . . . . . . . . . . . . . .   7
       3.4.1.  Collection Sub-Architecture . . . . . . . . . . . . .   7
       3.4.2.  Evaluation Sub-Architecture . . . . . . . . . . . . .  10
   4.  Interactions  . . . . . . . . . . . . . . . . . . . . . . . .  12
     4.1.  Interaction Categories  . . . . . . . . . . . . . . . . .  12
       4.1.1.  Broadcast . . . . . . . . . . . . . . . . . . . . . .  12
       4.1.2.  Directed  . . . . . . . . . . . . . . . . . . . . . .  13
     4.2.  Management Plane Functions  . . . . . . . . . . . . . . .  13
       4.2.1.  Orchestrator Onboarding . . . . . . . . . . . . . . .  13
       4.2.2.  Component Onboarding  . . . . . . . . . . . . . . . .  14
     4.3.  Component Interactions  . . . . . . . . . . . . . . . . .  15
       4.3.1.  Initiate Ad-Hoc Collection  . . . . . . . . . . . . .  15
       4.3.2.  Coordinate Periodic Collection  . . . . . . . . . . .  15
       4.3.3.  Coordinate Observational/Event-based
               Collection  . . . . . . . . . . . . . . . . . . . . .  16
       4.3.4.  Persist Collected Posture Attributes  . . . . . . . .  16
       4.3.5.  Initiate Ad-Hoc Evaluation  . . . . . . . . . . . . .  16
       4.3.6.  Coordinate Periodic Evaluation  . . . . . . . . . . .  16
       4.3.7.  Coordinate Change-based Evaluation  . . . . . . . . .  16
       4.3.8.  Queries . . . . . . . . . . . . . . . . . . . . . . .  17
   5.  Taxonomy  . . . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.1.  Orchestrator Registration . . . . . . . . . . . . . . . .  17
       5.1.1.  Topic . . . . . . . . . . . . . . . . . . . . . . . .  17
       5.1.2.  Interaction Type  . . . . . . . . . . . . . . . . . .  17
       5.1.3.  Initiator . . . . . . . . . . . . . . . . . . . . . .  17
       5.1.4.  Request Payload . . . . . . . . . . . . . . . . . . .  17
       5.1.5.  Receiver  . . . . . . . . . . . . . . . . . . . . . .  17
       5.1.6.  Process Description . . . . . . . . . . . . . . . . .  17
       5.1.7.  Response Payload  . . . . . . . . . . . . . . . . . .  18



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       5.1.8.  Response Processing . . . . . . . . . . . . . . . . .  18
     5.2.  Component Registration  . . . . . . . . . . . . . . . . .  18
       5.2.1.  Topic . . . . . . . . . . . . . . . . . . . . . . . .  18
       5.2.2.  Interaction Type  . . . . . . . . . . . . . . . . . .  18
       5.2.3.  Initiator . . . . . . . . . . . . . . . . . . . . . .  18
       5.2.4.  Request Payload . . . . . . . . . . . . . . . . . . .  18
       5.2.5.  Receiver  . . . . . . . . . . . . . . . . . . . . . .  19
       5.2.6.  Process Description . . . . . . . . . . . . . . . . .  19
       5.2.7.  Response Payload  . . . . . . . . . . . . . . . . . .  19
       5.2.8.  Response Processing . . . . . . . . . . . . . . . . .  19
     5.3.  Orchestrator-to-Component Administrative Interface  . . .  19
       5.3.1.  Capability Advertisement Handshake  . . . . . . . . .  20
       5.3.2.  Directed Collection . . . . . . . . . . . . . . . . .  21
       5.3.3.  Directed Evaluation . . . . . . . . . . . . . . . . .  21
       5.3.4.  Heartbeat . . . . . . . . . . . . . . . . . . . . . .  21
     5.4.  [Taxonomy Name] . . . . . . . . . . . . . . . . . . . . .  21
       5.4.1.  Topic . . . . . . . . . . . . . . . . . . . . . . . .  21
       5.4.2.  Interaction Type  . . . . . . . . . . . . . . . . . .  21
       5.4.3.  Initiator . . . . . . . . . . . . . . . . . . . . . .  21
       5.4.4.  Request Payload . . . . . . . . . . . . . . . . . . .  21
       5.4.5.  Receiver  . . . . . . . . . . . . . . . . . . . . . .  21
       5.4.6.  Process Description . . . . . . . . . . . . . . . . .  21
       5.4.7.  Response Payload  . . . . . . . . . . . . . . . . . .  21
       5.4.8.  Response Processing . . . . . . . . . . . . . . . . .  22
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  22
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  22
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  22
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  22
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  23
   Appendix A.  Security Domain Workflows  . . . . . . . . . . . . .  25
     A.1.  IT Asset Management . . . . . . . . . . . . . . . . . . .  25
       A.1.1.  Components, Capabilities and Workflow(s)  . . . . . .  25
     A.2.  Vulnerability Management  . . . . . . . . . . . . . . . .  26
       A.2.1.  Components, Capabilities and Workflow(s)  . . . . . .  27
     A.3.  Configuration Management  . . . . . . . . . . . . . . . .  27
       A.3.1.  Components, Capabilities and Workflow(s)  . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  30

1.  Introduction

   The purpose of this draft is to define an architectural approach for
   a SACM Domain, based on the spirit of use cases found in [RFC7632]
   and requirements found in [RFC8248].  This approach gains the most
   advantage by supporting a variety of collection systems, and intends
   to enable a cooperative ecosystem of tools from disparate sources
   with minimal operator configuration.




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1.1.  Requirements notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in RFC
   2119, BCP 14 [RFC2119].

2.  Terms and Definitions

   This draft defers to [I-D.ietf-sacm-terminology] for terms and
   definitions.

3.  Architectural Overview

   The generic approach proposed herein recognizes the need to obtain
   information from existing and future state collection systems, and
   makes every attempt to respect [RFC7632] and [RFC8248].  At the
   foundation of any architecture are entities, or components, that need
   to communicate.  They communicate by sharing information, where, in a
   given flow, one or more components are consumers of information and
   one or more components are providers of information.

          +----------------+
          | SACM Component |
          |   (Provider)   |
          +-------+--------+
                  |
                  |
   +--------------v----------------+
   |      Integration Service      |
   +--------------+----------------+
                  |
                  |
          +-------v--------+
          | SACM Component |
          |   (Consumer)   |
          +----------------+

                  Figure 1: Basic Architectural Structure

   A provider can be described as an abstraction that refers to an
   entity capable of sending SACM-relevant information to one or many
   consumers.  Consumers can be described as an abstraction that refers
   to an entity capable of receiving SACM-relevant information from one
   or many providers.  Different roles within a cooperative ecosystem
   may act as both providers and consumers of SACM-relevant information.





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3.1.  SACM Role-based Architecture

   Within the cooperative SACM ecosystem, a number of roles act in
   coordination to provide relevant policy/guidance, perform data
   collection, storage, evaluation, and support downstream analytics and
   reporting.

      +-----------------+     +--------------------+
      | Orchestrator(s) |     | Repositories/CMDBs |
      +---------^-------+     +----------^---------+
                |                        |             +--------------------+
                |                        |             |  Downstream Uses   |
                |                        |             | +----------------+ |
    +-----------v------------------------v------+      | |   Analytics    | |
    |             Integration Service           <------> +----------------+ |
    +-----------^--------------------------^----+      | +----------------+ |
                |                          |           | |   Reporting    | |
                |                          |           | +----------------+ |
    +-----------v-------------------+      |           +--------------------+
    |  Collection Sub-Architecture  |      |
    +-------------------------------+      |
                           +---------------v---------------+
                           |  Evaluation Sub-Architecture  |
                           +-------------------------------+

                 Figure 2: Notional Role-based Architecture

   As shown in Figure 2, the SACM role-based architecture consists of
   some basic SACM Components communicating using an integration
   service.  The integration service is expected to maximally align with
   the requirements described in [RFC8248], which means that the
   integration service will support brokered (i.e. point-to-point) and
   proxied data exchange.

3.2.  Architectural Roles/Components

   This document suggests a variety of players in a cooperative
   ecosystem; known as SACM Components.  SACM Components may be composed
   of other SACM Components, and each SACM Component plays one, or more,
   of several roles relevant to the ecosystem.  Roles may act as
   providers of information, consumers of information, or both provider
   and consumer.  Figure 2 depicts a number of SACM components which are
   architecturally significant and therefore warrant discussion and
   clarification.







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3.2.1.  Orchestrator(s)

   Orchestration components exists to aid in the automation of
   configuration, coordination, and management for the ecosystem of SACM
   components.  The Orchestrator performs control-plane operations,
   administration of an implementing organization's components
   (including endpoints, posture collection services, and downstream
   activities), scheduling of automated tasks, and any ad-hoc activities
   such as the initiation of collection or evaluation activities.  The
   Orchestrator is the key administrative interface into the SACM
   architecture.

3.2.2.  Repositories/CMDBs

   Figure 2 only includes a single reference to "Repositories/CMDBs",
   but in practice, a number of separate data repositories may exist,
   including posture attribute repositories, policy repositories, local
   vulnerability definition data repositories, and state assessment
   results repositories.  These data repositories may exist separately
   or together in a single representation, and the design of these
   repositories may be as distinct as their intended purpose, such as
   the use of relational database management systems or graph/map
   implementations focused on the relationships between data elements.
   Each implementation of a SACM repository should focus on the
   relationships between data elements and implement the SACM
   information and data model(s).

3.2.3.  Integration Service

   If each SACM component represents a set of capabilities, the
   Integration Service represents the "fabric" by which all those
   services are woven together.  The Integration Service acts as a
   message broker, combining a set of common message categories and
   infrastructure to allow SACM components to communicate using a shared
   set of interfaces.  The Integration Service's brokering capabilities
   enable the exchange of various information payloads, orchestration of
   component capabilities, message routing and reliable delivery.  The
   Integration Service minimizes the dependencies from one system to
   another through the loose coupling of applications through messaging.
   SACM components will "attach" to the Integration Service either
   through native support for the integration implementation, or through
   the use of "adapters" which provide a proxied attachment.

   The Integration Service should provide mechanisms for both
   synchronous and asynchronous "request/response"-style messaging, and
   a publish/subscribe mechanism to implement event-based messaging.  It
   is the responsibility of the Integration Service to coordinate and
   manage the sending and receiving of messages.  The Integration



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   Service should allow components the ability to directly connect and
   produce or consume messages, or connect via message translators which
   can act as a proxy, transforming messages from a component format to
   one implementing a SACM data model.

   The Integration Service MUST provide routing capabilities for
   payloads between producers and consumers.  The Integration Service
   MAY provide further capabilities within the payload delivery
   pipeline.  Examples of these capabilities include, but are not
   limited to, intermediate processing, message transformation, type
   conversion, validation, or other enterprise integration patterns.

3.3.  Downstream Uses

   As depicted by Figure 2, a number of downstream uses exist in the
   cooperative ecosystem.  Each notional SACM component represents
   distinct sub-architectures which will exchange information via the
   integration services, using interactions described in this draft.

3.3.1.  Reporting

   The Reporting component represents capabilities outside of the SACM
   architecture scope dealing with the query and retrieval of collected
   posture attribute information, evaluation results, etc. in various
   display formats that are useful to a wide range of stakeholders.

3.3.2.  Analytics

   The Analytics component represents capabilities outside of the SACM
   architecture scope dealing with the discovery, interpretation, and
   communication of any meaningful patterns of data in order to inform
   effective decision making within the organization.

3.4.  Sub-Architectures

   Figure 2 shows two components representing sub-architectural roles
   involved in a cooperative ecosystem of SACM components: Collection
   and Evaluation.

3.4.1.  Collection Sub-Architecture

   The Collection sub-architecture is, in a SACM context, the mechanism
   by which posture attributes are collected from applicable endpoints
   and persisted to a repository, such as a configuration management
   database (CMDB).  Orchestration components will choreograph endpoint
   data collection via defined interactions, using the Integration
   Service as a message broker.  Instructions to perform endpoint data
   collection are directed to a Posture Collection Service capable of



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   performing collection activities utilizing any number of methods,
   such as SNMP, NETCONF/RESTCONF, SSH, WinRM, packet capture, or host-
   based.

     +----------------------------------------------------------+
     |                    Orchestrator(s)                       |
     +-----------+----------------------------------------------+
                 |               +------------------------------+
                 |               | Posture Attribute Repository |
                 |               +--------------^---------------+
              Perform                           |
             Collection                         |
                 |                       Collected Data
                 |                              ^
                 |                              |
     +-----------v------------------------------+---------------+
     |                    Integration Service                   |
     +----+------------------^-----------+------------------^---+
          |                  |           |                  |
          v                  |           v                  |
       Perform           Collected    Perform           Collected
      Collection           Data      Collection           Data
          |                  ^           |                  ^
          |                  |           |                  |
     +----v-----------------------+ +----|------------------|------+
     | Posture Collection Service | |    |     Endpoint     |      |
     +---^------------------------+ | +--v------------------+----+ |
         |                   |      | |Posture Collection Service| |
         |                   v      | +--------------------------+ |
       Events             Queries   +------------------------------+
         ^                   |          (PCS resides on Endpoint)
         |                   |
     +---+-------------------v----+
     |          Endpoint          |
     +----------------------------+
   (PCS does not reside on Endpoint)

              Figure 3: Decomposed Collection Sub-Architecture

3.4.1.1.  Posture Collection Service

   The Posture Collection Service (PCS) is the SACM component
   responsible for the collection of posture attributes from an endpoint
   or set of endpoints.  A single PCS may be responsible for management
   of posture attribute collection from many endpoints.  The PCS will
   interact with the Integration Service to receive collection
   instructions and to provide collected posture data for persistence to
   the Posture Attribute Repository.  Collection instructions may be



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   supplied in a variety of forms, including subscription to a publish/
   subscribe topic to which the Integration Service has published
   instructions, or via request/response-style messaging (either
   synchronous or asynchronous).

   Four classifications of posture collections MAY be supported.

3.4.1.1.1.  Ad-Hoc

   Ad-Hoc collection is defined as a single colletion of posture
   attributes, collected at a particular time.  An example of ad-hoc
   collection is the single collection of a specific registry key.

3.4.1.1.2.  Continuous/Scheduled

   Continuous/Scheduled collection is defined as the ongoing, periodic
   collection of posture attributes.  An example of scheduled collection
   is the collection of a specific registry key value every day at a
   given time.

3.4.1.1.3.  Observational

   This classification of collection is triggered by the observation,
   external to an endpoint, of information asserting posture attribute
   values for that endpoint.  An example of observational collection is
   examination of netflow data for particular packet captures and/or
   specific information within those captures.

3.4.1.1.4.  Event-based

   Event-based collection may be triggered either internally or
   externally to the endpoint.  Internal event-based collection is
   triggered when a posture attribute of interest is added, removed, or
   modified on an endpoint.  This modification indicates a change in the
   current state of the endpoint, potentially affecting its adherence to
   some defined policy.  Modification of the endpoint's minimum password
   length is an example of an attribute change which could trigger
   collection.

   External event-based collection can be described as a collector being
   subscribed to an external source of information, receiving events
   from that external source on a periodic or continuous basis.  An
   example of event-based collection is subscription to YANG Push
   notifications.







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3.4.1.2.  Endpoint

   Building upon [I-D.ietf-sacm-terminology], the SACM Collection Sub-
   Architecture augments the definition of an Endpoint as a component
   within an organization's management domain from which a Posture
   Collection Service will collect relevant posture attributes.

3.4.1.3.  Posture Attribute Repository

   The Posture Attribute Repository is a SACM component responsible for
   the persistent storage of posture attributes collected via
   interactions between the Posture Collection Service and Endpoints.

3.4.1.4.  Posture Collection Workflow

   Posture collection may be triggered from a number of components, but
   commonly begin either via event-based triggering on an endpoint or
   through manual orchestration, both illustrated in Figure 3 above.
   Once orchestration has provided the directive to perform collection,
   posture collection services consume the directives.  Posture
   collection is invoked for those endpoints overseen by the respective
   posture collection services.  Collected data is then provided to the
   Integration Service, with a directive to store that information in an
   appropriate repository.

3.4.2.  Evaluation Sub-Architecture

   The Evaluation Sub-Architecture, in the SACM context, is the
   mechanism by which policy, expressed in the form of expected state,
   is compared with collected posture attributes to yield an evaluation
   result, that result being contextually dependent on the policy being
   evaluated.



















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                        +------------------+
                        |    Collection    |    +-------------------------------+
                        | Sub-Architecture |    | Evaluation Results Repository |
   +--------------+     +--------^---------+    +-----------------^-------------+
   | Orchestrator |              |                                |
   +------+-------+        (Potentially)                          |
          |                   Perform                 Store Evaluation Results
       Perform               Collection                           |
      Evaluation                 |                                |
          |                      |                                |
   +------v----------------------v--------------------------------+-------------+
   |                             Integration Service                            |
   +--------^----------------------^-----------------------^--------------------+
            |                      |                       |
            |                      |                       |
            |               Retrieve Posture            Perform
     Retrieve Policy           Attributes              Evaluation
            |                      |                       |
            |                      |                       |
     +------v-----+          +-----v------+       +--------v-------------------+
     |   Policy   |          |  Posture   |       | Posture Evaluation Service |
     | Repository |          | Attribute  |       +----------------------------+
     +------------+          | Repository |
                             +------------+

              Figure 4: Decomposed Evaluation Sub-Architecture

3.4.2.1.  Posture Evaluation Service

   The Posture Evaluation Service (PES) represents the SACM component
   responsible for coordinating the policy to be evaluated and the
   collected posture attributes relevant to that policy, as well as the
   comparison engine responsible for correctly determining compliance
   with the expected state.

3.4.2.2.  Policy Repository

   The Policy Repository represents a persistent storage mechanism for
   the policy to be assessed against collected posture attributes to
   determine if an endpoint meets the desired expected state.  Examples
   of information contained in a Policy Repository would be
   Vulnerability Definition Data or configuration recommendations as
   part of a CIS Benchmark or DISA STIG.








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3.4.2.3.  Evaluation Results Repository

   The Evaluation Results Repository persists the information
   representing the results of a particular posture assessment,
   indicating those posture attributes collected from various endpoints
   which either meet or do not meet the expected state defined by the
   assessed policy.  Consideration should be made for the context of
   individual results.  For example, meeting the expected state for a
   configuration attribute indicates a correct configuration of the
   endpoint, whereas meeting an expected state for a vulnerable software
   version indicates an incorrect configuration.

3.4.2.4.  Posture Evaluation Workflow

   Posture evaluation is orchestrated through the Integration Service to
   the appropriate Posture Evaluation Service (PES).  The PES will,
   using interactions defined by the applicable taxonomy, query both the
   Posture Attribute Repository and the Policy Repository to obtain
   relevant state data for comparison.  If necessary, the PES may be
   required to invoke further posture collection.  Once all relevant
   posture information has been collected, it is compared to expected
   state based on applicable policy.  Comparison results are then
   persisted to an evaluation results repository for further downstream
   use and analysis.

4.  Interactions

   SACM Components are intended to interact with other SACM Components.
   These interactions can be thought of, at the architectural level, as
   the combination of interfaces with their supported operations.  Each
   interaction will convey a payload of information.  The payload
   information is expected to contain sub-domain-specific
   characteristics and/or instructions.

4.1.  Interaction Categories

   Two categories of interactions SHOULD be supported by the Integration
   Service; broadcast and directed.

4.1.1.  Broadcast

   A broadcast interaction, commonly known as "publish/subscribe",
   allows for a wider distribution of a message payload.  When a payload
   is published to a topic on the Integration Service, all subscribers
   to that topic are alerted and may consume the message payload.  This
   category of interaction can also be described as a "unicast"
   interaction when a topic only has a single subscriber.  An example of
   a broadcast interaction could be to publish Linux OVAL objects to a



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   posture collection topic.  Subscribing consumers receive the
   notification, and proceed to collect endpoint configuration posture
   based on the new content.

4.1.2.  Directed

   The intent of a directed interaction is to enable point-to-point
   communications between a producer and consumer, through the standard
   interfaces provided by the Integration Service.  The provider
   component indicates which consumer is intended to receive the
   payload, and the Integration Service routes the payload directly to
   that consumer.  Two "styles" of directed interaction exist, differing
   only by the response from the payload consumer.

4.1.2.1.  Synchronous

   Synchronous, request/response style interaction requires that the
   requesting component block and wait for the receiving component to
   respond, or to time out when that response is delayed past a given
   time threshold.  A synchronous interaction example may be querying a
   CMDB for posture attribute information in order to perform an
   evaluation.

4.1.2.2.  Asynchronous

   An asynchronous interaction involves the payload producer directing
   the message to a consumer, but not blocking or waiting for an
   immediate response.  This style of interaction allows the producer to
   continue on to other activities without the need to wait for
   responses.  This style is particularly useful when the interaction
   payload invokes a potentially long-running task, such as data
   collection, report generation, or policy evaluation.  The receiving
   component may reply later via callbacks or further interactions, but
   it is not mandatory.

4.2.  Management Plane Functions

   Mangement plane functions describe a component's interactions with
   the ecosystem itself, not necessarily relating to collection,
   evaluation, or downstream analytical processes.

4.2.1.  Orchestrator Onboarding

   The Orchestrator component, being a specialized role in the
   architecture, onboards to the ecosystem in such a manner as to enable
   the onboarding and capabilities of the other component roles.  The
   Orchestrator must be enabled with the set of capabilities needed to
   manage the functions of the ecosystem.



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   With this in mind, the Orchestrator must first authenticate to the
   Integration Service.  Once authentication has succeeded, the
   Orchestrator must establish "service handlers" per the Section 5.2.
   Once "service handlers" have been established, the Orchestrator is
   then equipped to handle component registration, onboarding,
   capability discovery, and topic subscription policy.

   The following requirements exist for the Orchestrator to establish
   "service handlers" supporting the Section 5.2: - The Orchestrator
   MUST enable the capability to receive onboarding requests via the
   "/orchestrator/registration" topic, - The Orchestrator MUST have the
   capability to generate, manage, and persist unique identifiers for
   all registered components, - The Orchestrator MUST have the
   capability to inventory and manage its "roster" (the list of
   registered components), - The Orchestrator MUST support making
   directed requests to registered components over the component's
   administrative interface, as configured by the
   "/orchestrator/[component-unique-identifier]" topic.  Administrative
   interface functions are described by their taxonomy, below.

4.2.2.  Component Onboarding

   Component onboarding describes how an individual component becomes
   part of the ecosystem; registering with the orchestrator, advertising
   capabilities, establishing its administrative interface, and
   subscribing to relevant topics.

   The component onboarding workflow involves multiple steps: - The
   component first authenticates to the Integration Service - The
   component then initiates registration with the Orchestrator, per the
   Section 5.2

   Once the component has onboarded and registered with the
   Orchestrator, its administrative interface will have been established
   via the "/orchestrator/[component-unique-identifier]" topic.  This
   administrative interface allows the component to advertise its
   capabilities to the Orchestrator and in return, allow the
   Orchestrator to direct capability-specific topic registration to the
   component.  This is performed using the Section 5.3.1 taxonomy.
   Further described below, the "capability advertisement handshake"
   first assumes the onboarding component has the ability to describe
   its capabilities so they may be understood by the Orchestrator (TBD
   on capability advertisement methodology).

   *  The component sends a message with its operational capabilities
      over the administrative interface: "/orchestrator/[component-
      unique-identifier]"




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   *  The Orchestrator receives the component's capabilities, persists
      them, and responds with the list of topics to which the component
      should subscribe, in order to receive notifications, instructions,
      or other directives intended to invoke the component's supported
      capabilities.

   *  The component subscribes to the topics provided by the
      Orchestrator

4.3.  Component Interactions

   Component interactions describe functionality between components
   relating to collection, evaluation, or other downstream processes.

4.3.1.  Initiate Ad-Hoc Collection

   The Orchestrator supplies a payload of collection instructions to a
   topic or set of topics to which Posture Collection Services are
   subscribed.  The receiving PCS components perform the required
   collection based on their capabilities.  The PCS then forms a payload
   of collected posture attributes (including endpoint identifying
   information) and publishes that payload to the topic(s) to which the
   Posture Attribute Repository is subscribed, for persistence.

4.3.2.  Coordinate Periodic Collection

   Similar to ad-hoc collection, the Orchestrator supplies a payload of
   collection instructions containing additional information regarding
   collection periodicity, to the topic or topics to which Posture
   Collection Services are subscribed.

4.3.2.1.  Schedule Periodic Collection

   Collection instructions include information regarding the schedule
   for collection, for example, every day at Noon, or every hour at 32
   minutes past the hour.

4.3.2.2.  Cancel Periodic Collection

   The Orchestrator supplies a payload of instructions to a topic or set
   of topics to which Posture Collection Services are subscribed.  The
   receiving PCS components cancel the identified periodic collection
   executing on that PCS.








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4.3.3.  Coordinate Observational/Event-based Collection

   In these scenarios, the "observer" acts as the Posture Collection
   Service.  Interactions with the observer could specify a time period
   of observation and potentially information intended to filter
   observed posture attributes to aid the PCS in determining those
   attributes that are applicable for collection and persistence to the
   Posture Attribute Repository.

4.3.3.1.  Initiate Observational/Event-based Collection

   The Orchestrator supplies a payload of instructions to a topic or set
   of topics to which Posture Collection Services (observers) are
   subscribed.  This payload could include specific instructions based
   on the observer's capabilities to determine specific posture
   attributes to observe and collect.

4.3.3.2.  Cancel Observational/Event-based Collection

   The Orchestrator supplies a payload of instructions to a topic or set
   of topics to which Posture Collection Services are subscribed.  The
   receiving PCS components cancel the identified observational/event-
   based collection executing on that PCS.

4.3.4.  Persist Collected Posture Attributes

   [TBD] Normalization?

4.3.5.  Initiate Ad-Hoc Evaluation

   [TBD]

4.3.6.  Coordinate Periodic Evaluation

   [TBD]

4.3.6.1.  Schedule

   [TBD]

4.3.6.2.  Cancel

   [TBD]

4.3.7.  Coordinate Change-based Evaluation

   [TBD] i.e. if a posture attribute in the repository is changed,
   trigger an evaluation of particular policy items



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4.3.8.  Queries

   [TBD] Queries should allow for a "freshness" time period, allowing
   the requesting entity to determine if/when posture attributes must be
   re-collected prior to performing evaluation.  This freshness time
   period can be "zeroed out" for the purpose of automatically
   triggering re-collection regardless of the most recent collection.

5.  Taxonomy

5.1.  Orchestrator Registration

   The Orchestrator Registration taxonomy describes how an Orchestrator
   onboards to the ecosystem, or how it returns from a non-operational
   state.

5.1.1.  Topic

   N/A

5.1.2.  Interaction Type

   Directed (Request/Response)

5.1.3.  Initiator

   Orchestrator

5.1.4.  Request Payload

   N/A

5.1.5.  Receiver

   N/A

5.1.6.  Process Description

   Once the Orchestrator has authenticated to the Integration Service,
   it must establish (or re-establish) any service handlers interacting
   with administrative interfaces and/or general operational interfaces.

   For initial registration, the Orchestrator MUST enable capabilities
   to:

   *  Receive onboarding requests via the "/orchestrator/registration"
      topic,




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   *  Generate, manage, and persist unique identifiers for all
      registered components,

   *  Inventory and manage its "roster" (the list of registered
      components), and

   *  Support making directed requests to registered components over the
      component's administrative interface, as configured by the
      "/orchestrator/[component-unique-identifier]" topic.

   Administrative interfaces are to be re-established through the
   inventory of previously registered components, such as Posture
   Collection Services, Repositories, or Posture Evaluation Services.

5.1.7.  Response Payload

   N/A

5.1.8.  Response Processing

   N/A

5.2.  Component Registration

   Component onboarding describes how an individual component becomes
   part of the ecosystem; registering with the orchestrator, advertising
   capabilities, establishing its administrative interface, and
   subscribing to relevant topics.

5.2.1.  Topic

   "/orchestrator/registration"

5.2.2.  Interaction Type

   Directed (Request/Response)

5.2.3.  Initiator

   Any component wishing to join the ecosystem, such as Posture
   Collection Services, Repositories (policy, collection content,
   posture attribute, etc), Posture Evaluation Services and more.

5.2.4.  Request Payload

   [TBD] Information Elements, such as





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   *  identifying-information - component-type (i.e Posture Collection
      Service, Posture Evaluation Service, Repository, etc.) - name -
      description

5.2.5.  Receiver

   Orchestrator

5.2.6.  Process Description

   When the Orchestrator receives the component's request for
   onboarding, it will:

   *  Generate a unique identifier, "[component-unique-identifier]", for
      the onboarding component,

   *  Persist required information (TBD probably need more specifics),
      including the "[component-unique-identifier]" to its component
      inventory, enabling an up-to-date roster of components being
      orchestrated,

   *  Establish the administrative interface via the
      "/orchestrator/[component-unique-identifier]" topic.

5.2.7.  Response Payload

   [TBD] Information Elements

   *  component-unique-identifier

5.2.8.  Response Processing

   Successful receipt of the Orchestrator's response, including the
   "[component-unique-identifier]" indicates the component is onboarded
   to the ecosystem.  Using the response payload, the component can then
   establish its end of the administrative interface with the
   Orchestrator, using the "/orchestrator/[component-unique-identifier]"
   topic.  Given this administrative interface, the component can then
   initiate the Section 5.3.1

5.3.  Orchestrator-to-Component Administrative Interface

   A number of functions may take place which, instead of being
   published to a multi-subscriber topic, may require direct interaction
   between an Orchestrator and a registered component.  During component
   onboarding, this direct channel is established first by the
   Orchestrator and subsequently complemented by the onboarding
   component.



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5.3.1.  Capability Advertisement Handshake

   Capability advertisement, otherwise known as service discovery, is
   necessary to establish and maintain a cooperative ecosystem of tools.
   Using this capability advertisement "handshake", the Orchestrator
   becomes knowledgeable of a component's operational capabilities, the
   endpoints/services with which the component interacts, and
   establishes a direct mode of contact for invoking those capabilities.

5.3.1.1.  Topic

   "/orchestrator/[component-unique-identifier]"

5.3.1.2.  Interaction Type

   Directed (Request/Response)

5.3.1.3.  Initiator

   Any ecosystem component (minus the Orchestrator)

5.3.1.4.  Request Payload

   [TBD] Information Elements

   *  component-type

   *  component-unique-identifier

   *  interaction-type (capability-advertisement): - list of
      capabilities - list of endpoints/services

5.3.1.5.  Receiver

   Orchestrator

5.3.1.6.  Process Description

   Upon receipt of the component's capability advertisement, it SHOULD:
   - Persist the component's capabilities to the Orchestrator's
   inventory - Coordinate, based on the supplied capabilities, a list of
   topics to which the component should subscribe

5.3.1.7.  Response Payload

   [TBD] Information Elements

   *  a list of topics to which the receiver should subscribe



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5.3.1.8.  Response Processing

   Once the component has received the response to its capability
   advertisement, it should subscribe to the Orchestrator-provided
   topics.

5.3.2.  Directed Collection

5.3.3.  Directed Evaluation

5.3.4.  Heartbeat

5.4.  [Taxonomy Name]

   DESCRIPTION OF TAXONOMY

5.4.1.  Topic

   "/name/of/topic"

5.4.2.  Interaction Type

   [Directed (Request/Response) -or- Publish/Subscribe]

5.4.3.  Initiator

   [Component sending/publishing the payload]

5.4.4.  Request Payload

   DESCRIPTION OF INFORMATION MODEL OF REQUEST PAYLOAD; i.e. what
   elements need to be in whatever format in the payload.

5.4.5.  Receiver

   [Component receiving/subscribed-to the payload]

5.4.6.  Process Description

   [What the receiver does with the payload]

5.4.7.  Response Payload

   DESCRIPTION OF INFORMATION MODEL OF RESPONSE PAYLOAD; i.e. what
   elements need to be in whatever format in the payload.






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5.4.8.  Response Processing

   [What the initiator does with any response, if there is one]

6.  Privacy Considerations

   [TBD]

7.  Security Considerations

   [TBD]

8.  IANA Considerations

   [TBD] Revamp this section after the configuration assessment workflow
   is fleshed out.

   IANA tables can probably be used to make life a little easier.  We
   would like a place to enumerate:

   *  Capability/operation semantics

   *  SACM Component implementation identifiers

   *  SACM Component versions

   *  Associations of SACM Components (and versions) to specific
      Capabilities

   *  Collection sub-architecture Identification

9.  References

9.1.  Normative References

   [I-D.ietf-sacm-ecp]
              Haynes, D., Fitzgerald-McKay, J., and L. Lorenzin,
              "Endpoint Posture Collection Profile", draft-ietf-sacm-
              ecp-05 (work in progress), 21 June 2019,
              <http://www.ietf.org/internet-drafts/draft-ietf-sacm-ecp-
              05.txt>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.





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   [RFC8412]  Schmidt, C., Haynes, D., Coffin, C., Waltermire, D., and
              J. Fitzgerald-McKay, "Software Inventory Message and
              Attributes (SWIMA) for PA-TNC", RFC 8412,
              DOI 10.17487/RFC8412, July 2018,
              <https://www.rfc-editor.org/info/rfc8412>.

   [RFC8600]  Cam-Winget, N., Ed., Appala, S., Pope, S., and P. Saint-
              Andre, "Using Extensible Messaging and Presence Protocol
              (XMPP) for Security Information Exchange", RFC 8600,
              DOI 10.17487/RFC8600, June 2019,
              <https://www.rfc-editor.org/info/rfc8600>.

9.2.  Informative References

   [CISCONTROLS]
              "CIS Controls v7.0", May 2020,
              <https://www.cisecurity.org/controls>.

   [draft-birkholz-sacm-yang-content]
              Birkholz, H. and N. Cam-Winget, "YANG subscribed
              notifications via SACM Statements", May 2020,
              <https://tools.ietf.org/html/draft-birkholz-sacm-yang-
              content-01>.

   [HACK100]  "IETF 100 Hackathon - Vulnerability Scenario EPCP+XMPP",
              May 2020,
              <https://www.github.com/sacmwg/vulnerability-scenario/
              ietf-hackathon>.

   [HACK101]  "IETF 101 Hackathon - Configuration Assessment XMPP", May
              2020, <https://www.github.com/CISecurity/Integration>.

   [HACK102]  "IETF 102 Hackathon - YANG Collection on Traditional
              Endpoints", May 2020,
              <https://www.github.com/CISecurity/YANG>.

   [HACK103]  "IETF 103 Hackathon - N/A", May 2020,
              <https://www.ietf.org/how/meetings/103/>.

   [HACK104]  "IETF 104 Hackathon - A simple XMPP client", May 2020,
              <https://github.com/CISecurity/SACM-Architecture>.

   [HACK105]  "IETF 105 Hackathon - A more robust XMPP client including
              collection extensions", May 2020,
              <https://github.com/CISecurity/SACM-Architecture>.

   [HACK99]   "IETF 99 Hackathon - Vulnerability Scenario EPCP", May
              2020,



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              <https://www.github.com/sacmwg/vulnerability-scenario/
              ietf-hackathon>.

   [I-D.ietf-sacm-terminology]
              Birkholz, H., Lu, J., Strassner, J., Cam-Winget, N., and
              A. Montville, "Security Automation and Continuous
              Monitoring (SACM) Terminology", draft-ietf-sacm-
              terminology-16 (work in progress), 14 December 2018,
              <http://www.ietf.org/internet-drafts/draft-ietf-sacm-
              terminology-16.txt>.

   [NIST800126]
              Waltermire, D., Quinn, S., Booth, H., Scarfone, K., and D.
              Prisaca, "SP 800-126 Rev. 3 - The Technical Specification
              for the Security Content Automation Protocol (SCAP) - SCAP
              Version 1.3", February 2018,
              <https://csrc.nist.gov/publications/detail/sp/800-126/rev-
              3/final>.

   [NISTIR7694]
              Halbardier, A., Waltermire, D., and M. Johnson, "NISTIR
              7694 Specification for Asset Reporting Format 1.1", May
              2020,
              <https://csrc.nist.gov/publications/detail/nistir/7694/
              final>.

   [RFC5023]  Gregorio, J., Ed. and B. de hOra, Ed., "The Atom
              Publishing Protocol", RFC 5023, DOI 10.17487/RFC5023,
              October 2007, <https://www.rfc-editor.org/info/rfc5023>.

   [RFC7632]  Waltermire, D. and D. Harrington, "Endpoint Security
              Posture Assessment: Enterprise Use Cases", RFC 7632,
              DOI 10.17487/RFC7632, September 2015,
              <https://www.rfc-editor.org/info/rfc7632>.

   [RFC8248]  Cam-Winget, N. and L. Lorenzin, "Security Automation and
              Continuous Monitoring (SACM) Requirements", RFC 8248,
              DOI 10.17487/RFC8248, September 2017,
              <https://www.rfc-editor.org/info/rfc8248>.

   [RFC8322]  Field, J., Banghart, S., and D. Waltermire, "Resource-
              Oriented Lightweight Information Exchange (ROLIE)",
              RFC 8322, DOI 10.17487/RFC8322, February 2018,
              <https://www.rfc-editor.org/info/rfc8322>.

   [XMPPEXT]  "XMPP Extensions", May 2020,
              <https://xmpp.org/extensions/>.




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Appendix A.  Security Domain Workflows

   This section describes three primary information security domains
   from which workflows may be derived: IT Asset Management,
   Vulnerability Management, and Configuration Management.

A.1.  IT Asset Management

   Information Technology asset management is easier said than done.
   The [CISCONTROLS] have two controls dealing with IT asset management.
   Control 1, Inventory and Control of Hardware Assets, states,
   "Actively manage (inventory, track, and correct) all hardware devices
   on the network so that only authorized devices are given access, and
   unauthorized and unmanaged devices are found and prevented from
   gaining access."  Control 2, Inventory and Control of Software
   Assets, states, "Actively manage (inventory, track, and correct) all
   software on the network so that only authorized software is installed
   and can execute, and that unauthorized and unmanaged software is
   found and prevented from installation or execution."

   In spirit, this covers all of the processing entities on your network
   (as opposed to things like network cables, dongles, adapters, etc.),
   whether physical or virtual, on-premises or in the cloud.

A.1.1.  Components, Capabilities and Workflow(s)

   TBD

A.1.1.1.  Components

   TBD

A.1.1.2.  Capabilities

   An IT asset management capability needs to be able to:

   *  Identify and catalog new assets by executing Target Endpoint
      Discovery Tasks

   *  Provide information about its managed assets, including uniquely
      identifying information (for that enterprise)

   *  Handle software and/or hardware (including virtual assets)

   *  Represent cloud hybrid environments






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A.1.1.3.  Workflow(s)

   TBD

A.2.  Vulnerability Management

   Vulnerability management is a relatively established process.  To
   paraphrase the [CISCONTROLS], continuous vulnerability management is
   the act of continuously acquiring, assessing, and taking subsequent
   action on new information in order to identify and remediate
   vulnerabilities, therefore minimizing the window of opportunity for
   attackers.

   A vulnerability assessment (i.e. vulnerability detection) is
   performed in two steps:

   *  Endpoint information collected by the endpoint management
      capabilities is examined by the vulnerability management
      capabilities through Evaluation Tasks.

   *  If the data possessed by the endpoint management capabilities is
      insufficient, a Collection Task is triggered and the necessary
      data is collected from the target endpoint.

   Vulnerability detection relies on the examination of different
   endpoint information depending on the nature of a specific
   vulnerability.  Common endpoint information used to detect a
   vulnerability includes:

   *  A specific software version is installed on the endpoint

   *  File system attributes

   *  Specific state attributes

   In some cases, the endpoint information needed to determine an
   endpoint's vulnerability status will have been previously collected
   by the endpoint management capabilities and available in a
   Repository.  However, in other cases, the necessary endpoint
   information will not be readily available in a Repository and a
   Collection Task will be triggered to perform collection from the
   target endpoint.  Of course, some implementations of endpoint
   management capabilities may prefer to enable operators to perform
   this collection even when sufficient information can be provided by
   the endpoint management capabilities (e.g. there may be freshness
   requirements for information).





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A.2.1.  Components, Capabilities and Workflow(s)

   TBD

A.2.1.1.  Components

   TBD

A.2.1.2.  Capabilities

   TBD

A.2.1.3.  Workflow(s)

   TBD

A.3.  Configuration Management

   Configuration management involves configuration assessment, which
   requires state assessment.  The [CISCONTROLS] specify two high-level
   controls concerning configuration management (Control 5 for non-
   network devices and Control 11 for network devices).  As an aside,
   these controls are listed separately because many enterprises have
   different organizations for managing network infrastructure and
   workload endpoints.  Merging the two controls results in the
   following paraphrasing: Establish, implement, and actively manage
   (track, report on, correct) the security configuration of systems
   using a rigorous configuration management and change control process
   in order to prevent attackers from exploiting vulnerable services and
   settings.

   Typically, an enterprise will use configuration guidance from a
   reputable source, and from time to time they may tailor the guidance
   from that source prior to adopting it as part of their enterprise
   standard.  The enterprise standard is then provided to the
   appropriate configuration assessment tools and they assess endpoints
   and/or appropriate endpoint information.

   A preferred flow follows:

   *  Reputable source publishes new or updated configuration guidance

   *  Enterprise configuration assessment capability retrieves
      configuration guidance from reputable source

   *  Optional: Configuration guidance is tailored for enterprise-
      specific needs




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   *  Configuration assessment tool queries asset inventory repository
      to retrieve a list of affected endpoints

   *  Configuration assessment tool queries configuration state
      repository to evaluate compliance

   *  If information is stale or unavailable, configuration assessment
      tool triggers an ad hoc assessment

   The SACM architecture needs to support varying deployment models to
   accommodate the current state of the industry, but should strongly
   encourage event-driven approaches to monitoring configuration.

A.3.1.  Components, Capabilities and Workflow(s)

   This section provides more detail about the components and
   capabilities required when considering the aforementioned
   configuration management workflow.

A.3.1.1.  Components

   The following is a minimal list of SACM Components required to
   implement the aforementioned configuration assessment workflow.

   *  Configuration Policy Feed: An external source of authoritative
      configuration recommendations.

   *  Configuration Policy Repository: An internal repository of
      enterprise standard configurations.

   *  Configuration Assessment Orchestrator: A component responsible for
      orchestrating assessments.

   *  Posture Attribute Collection Subsystem: A component responsible
      for collection of posture attributes from systems.

   *  Posture Attribute Repository: A component used for storing system
      posture attribute values.

   *  Configuration Assessment Evaluator: A component responsible for
      evaluating system posture attribute values against expected
      posture attribute values.

   *  Configuration Assessment Results Repository: A component used for
      storing evaluation results.






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A.3.1.2.  Capabilities

   Per [RFC8248], solutions MUST support capability negotiation.
   Components implementing specific interfaces and operations (i.e.
   interactions) will need a method of describing their capabilities to
   other components participating in the ecosystem; for example, "As a
   component in the ecosystem, I can assess the configuration of
   Windows, MacOS, and AWS using OVAL".

A.3.1.3.  Configuration Assessment Workflow

   This section describes the components and interactions in a basic
   configuration assessment workflow.  For simplicity, error conditions
   are recognized as being necessary and are not depicted.  When one
   component messages another component, the message is expected to be
   handled appropriately unless there is an error condition, or other
   notification, messaged in return.

   +-------------+  +----------------+  +------------------+  +------------+
   | Policy Feed |  |  Orchestrator  |  |    Evaluation    |  | Evaluation |
   +------+------+  +-------+--------+  | Sub-Architecture |  |   Results  |
          |                 |           +---^----------+---+  | Repository |
          |                 |               |          |      +------^-----+
          |                 |               |          |             |
        1.|               3.|             8.|        9.|          10.|
          |                 |               |          |             |
          |                 |               |          |             |
   +------v-----------------v---------------+----------v-------------+-----+
   |                           Integration Service                         |
   +-----+----------------------------------+----------^---------+------^--+
         |                                  |          |         |      |
         |                                  |          |         |      |
       2.|                                4.|        5.|       6.|    7.|
         |                                  |          |         |      |
         |                                  |          |         |      |
   +-----v------+                       +---v----------+---+  +--v------+--+
   |   Policy   |                       |    Collection    |  |  Posture   |
   | Repository |                       | Sub-Architecture |  | Attribute  |
   +------------+                       +------------------+  | Repository |
                                                              +------------+

         Figure 5: Configuration Assessment Component Interactions

   Figure 5 depicts configuration assessment components and their
   interactions, which are further described below.

   1.   A policy feed provides a configuration assessment policy payload
        to the Integration Service.



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   2.   The Policy Repository, a consumer of Policy Feed information,
        receives and persists the Policy Feed's payload.

   3.   Orchestration component(s), either manually invoked, scheduled,
        or event-based, publish a payload to begin the configuration
        assessment process.

   4.   If necessary, Collection Sub-Architecture components may be
        invoked to collect neeeded posture attribute information.

   5.   If necessary, the Collection Sub-Architecture will provide
        collected posture attributes to the Integration Service for
        persistence to the Posture Attribute Repository.

   6.   The Posture Attribute Repository will consume a payload querying
        for relevant posture attribute information.

   7.   The Posture Attribute Repository will provide the requested
        information to the Integration Service, allowing further
        orchestration payloads requesting the Evaluation Sub-
        Architecture perform evaluation tasks.

   8.   The Evaluation Sub-Architecture consumes the evaluation payload
        and performs component-specific state comparison operations to
        produce evaluation results.

   9.   A payload containing evaluation results are provided by the
        Evaluation Sub-Architecture to the Integration Service

   10.  Evaluation results are consumed by/persisted to the Evaluation
        Results Repository

   In the above flow, the payload information is expected to convey the
   context required by the receiving component for the action being
   taken under different circumstances.  For example, a directed message
   sent from an Orchestrator to a Collection sub-architecture might be
   telling that Collector to watch a specific posture attribute and
   report only specific detected changes to the Posture Attribute
   Repository, or it might be telling the Collector to gather that
   posture attribute immediately.  Such details are expected to be
   handled as part of that payload, not as part of the architecture
   described herein.

Authors' Addresses

   Adam W. Montville
   Center for Internet Security
   31 Tech Valley Drive



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   East Greenbush, NY 12061
   United States of America

   Email: adam.montville.sdo@gmail.com


   Bill Munyan
   Center for Internet Security
   31 Tech Valley Drive
   East Greenbush, NY 12061
   United States of America

   Email: bill.munyan.ietf@gmail.com






































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