SACM Working Group A. Montville
Internet-Draft B. Munyan
Intended status: Standards Track CIS
Expires: 14 March 2021 10 September 2020
Security Automation and Continuous Monitoring (SACM) Architecture
draft-ietf-sacm-arch-07
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
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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
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This Internet-Draft will expire on 14 March 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 4
3. Architectural Overview . . . . . . . . . . . . . . . . . . . 4
3.1. SACM Role-based Architecture . . . . . . . . . . . . . . 4
3.2. Architectural Roles/Components . . . . . . . . . . . . . 5
3.2.1. Orchestrator(s) . . . . . . . . . . . . . . . . . . . 6
3.2.2. Repositories/Configuration Management Databases
(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 . . . . . . . . . . . . . 8
3.4.2. Evaluation Sub-Architecture . . . . . . . . . . . . . 10
4. Interactions . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. Interaction Categories . . . . . . . . . . . . . . . . . 12
4.1.1. Broadcast . . . . . . . . . . . . . . . . . . . . . . 13
4.1.2. Directed . . . . . . . . . . . . . . . . . . . . . . 13
4.2. Management Plane Functions . . . . . . . . . . . . . . . 14
4.2.1. Orchestrator Onboarding . . . . . . . . . . . . . . . 14
4.2.2. Component Onboarding . . . . . . . . . . . . . . . . 15
4.3. Component Interactions . . . . . . . . . . . . . . . . . 16
4.3.1. Initiate Ad-Hoc Collection . . . . . . . . . . . . . 16
4.3.2. Coordinate Periodic Collection . . . . . . . . . . . 16
4.3.3. Coordinate Observational/Event-based Collection . . . 17
4.3.4. Persist Collected Posture Attributes . . . . . . . . 18
4.3.5. Initiate Ad-Hoc Evaluation . . . . . . . . . . . . . 18
4.3.6. Coordinate Periodic Evaluation . . . . . . . . . . . 18
4.3.7. Coordinate Change-based Evaluation . . . . . . . . . 19
4.3.8. Queries . . . . . . . . . . . . . . . . . . . . . . . 19
5. Taxonomy . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1. Orchestrator Registration . . . . . . . . . . . . . . . . 19
5.1.1. Interaction . . . . . . . . . . . . . . . . . . . . . 20
5.1.2. Request Payload . . . . . . . . . . . . . . . . . . . 20
5.1.3. Request Processing . . . . . . . . . . . . . . . . . 20
5.1.4. Response Payload . . . . . . . . . . . . . . . . . . 21
5.1.5. Response Processing . . . . . . . . . . . . . . . . . 21
5.2. Component Registration . . . . . . . . . . . . . . . . . 21
5.2.1. Interaction . . . . . . . . . . . . . . . . . . . . . 21
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5.2.2. Request Payload . . . . . . . . . . . . . . . . . . . 21
5.2.3. Request Processing . . . . . . . . . . . . . . . . . 22
5.2.4. Response Payload . . . . . . . . . . . . . . . . . . 22
5.2.5. Response Processing . . . . . . . . . . . . . . . . . 23
5.3. Orchestrator-Component Administrative Interface . . . . . 23
5.3.1. Capability Advertisement Handshake . . . . . . . . . 23
5.3.2. Heartbeat . . . . . . . . . . . . . . . . . . . . . . 25
5.4. Collection . . . . . . . . . . . . . . . . . . . . . . . 27
5.4.1. Ad-Hoc . . . . . . . . . . . . . . . . . . . . . . . 27
5.4.2. Periodic . . . . . . . . . . . . . . . . . . . . . . 29
5.4.3. Observational/Event-based . . . . . . . . . . . . . . 31
5.5. Evaluation . . . . . . . . . . . . . . . . . . . . . . . 31
5.5.1. Ad-Hoc . . . . . . . . . . . . . . . . . . . . . . . 32
5.5.2. Periodic . . . . . . . . . . . . . . . . . . . . . . 32
5.5.3. Change/Event-based . . . . . . . . . . . . . . . . . 32
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 32
7. Security Considerations . . . . . . . . . . . . . . . . . . . 32
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
9.1. Normative References . . . . . . . . . . . . . . . . . . 32
9.2. Informative References . . . . . . . . . . . . . . . . . 33
Appendix A. Security Domain Workflows . . . . . . . . . . . . . 34
A.1. IT Asset Management . . . . . . . . . . . . . . . . . . . 35
A.1.1. Components, Capabilities and Workflow(s) . . . . . . 35
A.2. Vulnerability Management . . . . . . . . . . . . . . . . 36
A.2.1. Components, Capabilities and Workflow(s) . . . . . . 36
A.3. Configuration Management . . . . . . . . . . . . . . . . 37
A.3.1. Components, Capabilities and Workflow(s) . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
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.
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].
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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. A Consumer 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.
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.
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+-----------------+ +--------------------+
| 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)
Orchestrator 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.
Topic authorization policies established by the Integration Service
should dictate that only the component acting as the Orchestrator has
access to receive messages on the administrative topic(s) used for
component onboarding (i.e. the "/orchestrator/registration" topic).
3.2.2. Repositories/Configuration Management Databases (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, then the
Integration Service represents the "fabric" by which SACM components
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.
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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
Service should allow components 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.
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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
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
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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
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.
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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.
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. Broadcast interactions are
asynchronous by default, and directed interactions may be invoked
either synchronously or asynchronously. Each interaction category
SHOULD adhere to topic naming conventions described below.
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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
posture collection topic. Subscribing consumers receive the
notification, and proceed to collect endpoint configuration posture
based on the new content.
When interacting via broadcast, topic naming conventions should
provide an adequate amount of information to be deterministic
regarding the purpose of the interaction. For example, a broadcast
topic named "/collection/oval" would indicate that (a) the payloads
published to the topic are represented as OVAL definitions, and that
(b) subscribers to that topic have advertised capabilities to perform
collection using an OVAL-compliant engine.
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.
When interacting via directed messaging, topic naming conventions
should provide an adequate amount of information to be deterministic
regarding the operation(s) to be performed, and the component
performing them. For example, a topic named "/collector-1234/ad-hoc-
collection" would indicate a payload of collection instructions,
provided to a specific component identified as "collector-1234",
directing that component to perform Ad-Hoc Collection.
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.
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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 SACM ecosystem in such a manner as to
enable the onboarding and capability management of the other
component roles. The Orchestrator must support the set of
capabilities needed to manage the functions of the ecosystem.
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 component
registration taxonomy (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 component registration taxonomy
(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),
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* The Orchestrator MUST have the capability to manage its roster's
advertised capabilities, including those endpoints to which those
capabilities apply.
In addition to supporting component registration, Orchestrators are
responsible for many of the operational functions of the
architecture, including initiating collection or evaluation, queries
for repository data, or the assembly of information for downstream
use.
* 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.
* The Orchestrator MUST support the publication of broadcast
messages to topics configured by implementations of this
ecosystem.
* The Orchestrator MUST support the subscription to topics
configured by implementations of this ecosystem as needed.
4.2.2. Component Onboarding
Component onboarding describes how an individual component becomes
part of the SACM 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, and
* The component initiates registration with the Orchestrator, per
the component registration taxonomy (Section 5.2).
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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 "capability advertisement
handshake" (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]"
* 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 then subscribes to the topics provided by the
Orchestrator in order to enable receipt of broadcast instructions.
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. Each 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 similar to those of ad-hoc collection.
Additional information elements containing collection identification
and periodicity are included.
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4.3.2.1. Schedule Periodic Collection
To enable operations on periodic collection, the scheduling payload
MUST include both a unique identifier for the set of collection
instructions, as well as a periodicity expression to enable the
collection schedule. An optional "immediate collection" flag will
indicate to the collection component that, upon receipt of the
collection instructions, a collection will automatically be initiated
prior to engagement of the scheduled collection.
4.3.2.2. Cancel Periodic Collection
The Orchestrator disables the periodic collection of posture
attributes by supplying collector(s) the unique identifier of
previously scheduled collection instructions. An optional "final
collection" flag will indicate to the collection component that, upon
receipt of the cancellation instructions, a final ad-hoc collection
is to take place.
4.3.3. Coordinate Observational/Event-based Collection
In these scenarios, the Posture Collection Service acts as the
"observer". 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 those PCS components.
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4.3.4. Persist Collected Posture Attributes
Following successful collection, Posture Collection Services (PCS)
will supply the payload of collected posture attributes to the
interface(s) supporting the persistent storage of those attributes to
the Posture Attribute Repository. Information in this payload should
include identifying information of the computing resource(s) for
which attributes were collected.
4.3.5. Initiate Ad-Hoc Evaluation
The Orchestrator supplies a payload of evaluation instructions to a
topic or set of topics to which Posture Evaluation Services (PES) are
subscribed. The receiving PES components perform the required
evaluation based on their capabilities. The PES generates a payload
of posture evaluation results and publishes that payload to the
appropriate topic(s), to which the Evaluation Results Repository is
subscribed, for persistence.
4.3.6. Coordinate Periodic Evaluation
Similar to ad-hoc evaluation, the Orchestrator supplies a payload of
evaluation instructions similar to those of ad-hoc evaluation.
Additional information elements containing evaluation identification
and periodicity are included.
4.3.6.1. Schedule Periodic Evaluation
To enable operations on periodic evaluation, the scheduling payload
MUST include both a unique identifier for the set of evaluation
instructions, as well as a periodicity expression to enable the
evaluation schedule. An optional "immediate evaluation" flag will
indicate to the Posture Evaluation Service (PES) that, upon receipt
of the evaluation instructions, an evaluation will automatically be
initiated prior to engagement of the scheduled evaluation.
4.3.6.2. Cancel Periodic Evaluation
The Orchestrator disables the periodic evaluation of posture
attributes by supplying Posture Evaluation Service(s) the unique
identifier of previously scheduled evaluation instructions. An
optional "final evaluation" flag will indicate to the PES that, upon
receipt of the cancellation instructions, a final ad-hoc evaluation
is to take place.
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4.3.7. Coordinate Change-based Evaluation
A more fine-grained approach to periodic evaluation may be enabled
through the triggering of Posture Evaluation based on changes to
posture attribute values at the time of their collection and
persistence to the Posture Attribute Repository.
4.3.7.1. Identify Attributes
The Orchestrator enables change-based evaluation through a payload
published to Posture Attribute Repository component(s). This payload
includes appropriate information elements describing the posture
attributes on which changes in value will trigger posture evaluation.
4.3.7.2. Cancel Change-based Evaluation
An Orchestrator may disable change-based evaluation through a payload
published to Posture Attribute Repository component(s), including
those information elements necessary to identify those posture
attributes for which change-based evaluation no longer applies.
4.3.8. Queries
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
The following sections describe a number of operations required to
enable a cooperative ecosystem of posture attribute collection and
evaluation functions.
5.1. Orchestrator Registration
The Orchestrator Registration taxonomy describes how an Orchestrator
onboards to the SACM ecosystem, or how it returns from a non-
operational state.
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5.1.1. Interaction
+=====================+=============================+
| Property | Value |
+=====================+=============================+
| Type | Directed (Request/Response) |
+---------------------+-----------------------------+
| Topic | N/A |
+---------------------+-----------------------------+
| Source Component | Orchestrator |
+---------------------+-----------------------------+
| Target Component(s) | N/A |
+---------------------+-----------------------------+
Table 1
5.1.2. Request Payload
N/A;
5.1.3. Request Processing
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,
* 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.
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5.1.4. Response Payload
N/A
5.1.5. Response Processing
N/A
5.2. Component Registration
Component onboarding describes how an individual component becomes
part of the SACM ecosystem; registering with the orchestrator,
advertising capabilities, establishing its administrative interface,
and subscribing to relevant topics.
5.2.1. Interaction
+==============+==============================================+
| Property | Value |
+==============+==============================================+
| Type | Directed (Request/Response) |
+--------------+----------------------------------------------+
| Topic | /orchestrator/registration |
+--------------+----------------------------------------------+
| Source | Any component wishing to join the ecosystem, |
| Component | such as Posture Collection Services, |
| | Repositories (policy, collection content, |
| | posture attribute, evaluation results, |
| | etc.), Posture Evaluation Services and more. |
+--------------+----------------------------------------------+
| Target | Orchestrator |
| Component(s) | |
+--------------+----------------------------------------------+
Table 2
5.2.2. Request Payload
When a component registers with the Orchestrator and enters the
ecosystem, it must first identify itself to the Orchestrator.
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component-registration-request:
component-unique-identifier (if re-establishing communication)
#-OR-#
{:component-identification:}
component-identification:
component-type {:component-type:}
component-name
component-description (optional)
component-type:
enumeration:
- posture-collection-service
- posture-evaluation-service
- repository
- orchestrator
- others?
When registering for the first time, the component will send
identifying information including the component type and a name. If
the component is reestablishing communications, for example after a
restart of the component or deployment of a new version, the
component only needs to supply its previously generated unique
identifier.
5.2.3. Request Processing
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.
5.2.4. Response Payload
The Orchestrator will respond to the component with a payload
including the component's unique identifier. At this point, the
Orchestrator is aware of the component's existence in the ecosystem,
and the component is self-aware by virtue of receiving its unique
identifier.
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component-registration-response:
component-unique-identifier: [component-unique-identifier]
5.2.5. 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-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 component entering
the ecosystem.
5.3.1. Capability Advertisement Handshake
Capability advertisement, otherwise known as service discovery, is
necessary to establish and maintain a cooperative ecosystem of tools
by allowing components to register and maintain supported
capabilities with the orchestrator. 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. Once initially established,
orchestrators and components can maintain this capability matrix
using the administrative interface.
5.3.1.1. Interaction
+==================+=============================================+
| Property | Value |
+==================+=============================================+
| Type | Directed (Request/Response) |
+------------------+---------------------------------------------+
| Topic | /orchestrator/[component-unique-identifier] |
+------------------+---------------------------------------------+
| Source Component | Any ecosystem component (minus the |
| | Orchestrator) |
+------------------+---------------------------------------------+
| Target | Orchestrator |
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| Component(s) | |
+------------------+---------------------------------------------+
Table 3
5.3.1.2. Request Payload
capability-advertisement-request:
component-unique-identifier: [component-unique-identifier]
component-type: {:component-type:}
capabilities:
capability-urn: [urn]
capability-urn: [urn]
capability-urn: [urn]
...
[TBD] Start adding capability URNs to IANA considerations section?
5.3.1.3. Request Processing
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
[TBD] What if the component supplies a "capability-urn" that the
Orchestrator doesn't know about?
5.3.1.4. Response Payload
When responding, the Orchestrator will indicate to the component,
which capabilities were successfully registered, and the topics to
which those capabilities apply. Any failures to register
capabilities will also be noted per capability URN, including any
relevant error messages.
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capability-advertisement-response:
capabilities:
capability:
capability-urn: [urn]
registration-status: (success | failure)
capability-topic: /capability/topic/name
messages: [messages]
capability:
capability-urn: [urn]
registration-status: (success | failure)
capability-topic: /capability/topic/name
messages: [messages]
...
5.3.1.5. Response Processing
Once the component has received the response to its capability
advertisement, it should subscribe to the Orchestrator-provided
topics. Once the applicable topics have been subscribed, the
component is considered fully onboarded to the ecosystem.
5.3.2. Heartbeat
As time passes and ecosystem components which have previously
registered with the ecosystem are brought offline (perhaps for
maintenance or redeployment) and back online, it is important that
the Orchestrator maintains knowledge of all registered component's
current operational status. The heartbeat taxonomy describes the
efforts taken by an Orchestrator to maintain the most up-to-date
inventory of operational components, and to potentially alert users
or other outside systems of unavailable components.
5.3.2.1. Interaction
+=====================+=============================================+
| Property | Value |
+=====================+=============================================+
| Type | Directed (Request/Response) |
+---------------------+---------------------------------------------+
| Topic | /orchestrator/[component-unique-identifier] |
+---------------------+---------------------------------------------+
| Source Component | Orchestrator |
+---------------------+---------------------------------------------+
| Target | Any non-Orchestrator component maintained |
| Component(s) | in the current operational inventory |
+---------------------+---------------------------------------------+
Table 4
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5.3.2.2. Request Payload
The request payload defines the hearbeat action to be taken:
heartbeat-request:
action: (ping | ping-with-capabilities)
5.3.2.3. Request Processing
When the target component receives the hearbeat request, it will
determine based on action, the processing required. A simple "ping"
request indicates the target component need only respond that it is
operational and connected to the integration service. This is a
simple "Are you listening? Yes, I am" interaction. The heartbeat
request from the Orchestrator should be made with an appropriately
small timeout indicator; only an operational component will be able
to respond to the request, so if that component is offline and cannot
respond, the Orchestrator should not be kept waiting for an extended
amount of time.
When the requested action is "ping-with-capabilities", the receiving
component is instructed to respond that it is operational and to
immediately follow the response with a re-initiation of the
Section 5.3.1 process. This interaction enables an Orchestrator the
ability to perform capability discovery from components.
5.3.2.4. Response Payload
When responding to the heartbeat request, the initial response
payload will simply indicate success: ~~~~~~ heartbeat-response:
response: success ~~~~~~
If the "ping-with-capabilities" action was requested, the responding
component will immediately initiate the Section 5.3.1 process.
5.3.2.5. Response Processing
Upon receipt of the "heartbeat-response" payload, the Orchestrator
will update its inventory of currently operational components with
the timestamp of the receipt. If the Orchestrator originally
requested the component's capabilities as well, further interactions
will initiate and complete the Section 5.3.1 process.
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5.4. Collection
The following sections detail the interactions supporting the
collection of posture attributes from one or many endpoints within
the ecosystem. Collector capabilities will determine both the set of
endpoints each collector from which posture attributes may be
collected, as well as the various methods of collection used by those
collectors.
5.4.1. Ad-Hoc
Collection components support ad-hoc collection activities when
receiving collection instructions from an Orchestrator and by acting
upon those instructions immediately, collecting posture attributes as
they exist on targeted endpoints at the moment of collection. Ad-Hoc
collection may potentially be invoked by a number of components,
including Orchestrators or even Posture Evaluation Services, and may
be requested of Collectors either directly or through the Collector's
subscription to topics as established by the Section 5.3.1 process.
5.4.1.1. Interaction
+==============+===================================================+
| Property | Value |
+==============+===================================================+
| Type | Directed or Broadcast |
+--------------+---------------------------------------------------+
| Topic | <ul><li>The Orchestrator-Component Administrative |
| | Interface: "/orchestrator/[component-unique- |
| | identifier]",</li><li>Component-specific |
| | Collection topic: "/[component-unique- |
| | identifier]/collect", or</li><li>Through |
| | subscriptions such as "/collection/[collection- |
| | type]"</li></ul> |
+--------------+---------------------------------------------------+
| Source | Orchestrator, Posture Evaluation Service |
| Component | |
+--------------+---------------------------------------------------+
| Target | Collector |
| Component(s) | |
+--------------+---------------------------------------------------+
Table 5
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5.4.1.2. Request Payload
Ad-Hoc collection requests take the form of collection instructions
corresponding to the SACM information model. Collection instruction
payloads MAY be serialized as a specific collection language
supported by the Collector (taking into account any implementation-
specific payload size limitations), as a generic serialization to be
interpreted by the Collector, or as ID references to content
persisted in a Repository.
Instructions MAY include a "response topic" to which collection
results are published/directed. This can allow the requesting
component to direct a Collector (or Collectors) to publish results
directly to a Posture Attribute Repository component, or to simply
respond to the requesting component.
collection-request:
[TBD]
response-topic: [response-topic]
5.4.1.3. Request Processing
Upon receipt of collection instructions, the Collector will need to
determine whether or not any normalization or retrieval of specific
instructions is required. This normalization may be required if
collection instructions are not formatted specifically to the
capabilities of the Collector. For example, if a payload is
delivered containing a set of OVAL "object" IDs, the Collector would
need to retrieve the instructions from the Repository and format them
into a well-formed, valid OVAL definitions serialization for
processing.
Once the collection instructions have been received and any pre-
processing/normalization has occurred, the Collector will perform the
actual retrieval of posture attributes. Once collected, posture
attributes will need to be published back to the topic named in the
request payload. This response topic could represent a callback to
the component invoking collection, or a destination for the posture
attributes to be persisted, i.e. a Repository.
5.4.1.4. Response Payload
The response payload generated by the Collector may take one of 2
forms:
* Collection results using the data model supported by the
collection system indicated in the collection instructions. For
example, if the collection instructions were formatted as OVAL
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definitions (or more specifically OVAL objects), then collection
results would be formatted as OVAL system characteristics. Each
collector is responsible for maintaining the capabilities
necessary to produce results formats based on its collection
capabilities.
* Collection results using a "normalized" [TBD] format as defined by
the SACM information model/data models.
5.4.1.5. Response Processing
Handling a payload of collected posture attributes will vary based on
the component receiving that payload:
* Posture Attribute Repository: If collection results are not
"normalized" the Repository component MUST be able to perform
normalization processing prior to persisting the results.
* Non-Repository Components: The receiving component must also be
capable of "normalizing" collected posture attributes
5.4.2. Periodic
Periodic collection builds upon Ad-Hoc collection by allowing
Orchestration of collection activities given a periodicity.
Architecturally, periodic collection is orchestrated through either
the scheduling of collection or canceling an already-existing
schedule. Modifications to a scheduled collection MUST be made by
first canceling the existing schedule and establishing the updated
schedule.
5.4.2.1. Schedule Periodic Collection
Scheduling periodic collection is established by an Orchestrator
delivering collection instructions and the collection periodicity to
a Collector. These instructions may be received by the Collector
through a number of topics, described below.
5.4.2.1.1. Interaction
+==============+===================================================+
| Property | Value |
+==============+===================================================+
| Type | Directed or Broadcast |
+--------------+---------------------------------------------------+
| Topic | <ul><li>The Orchestrator-Component Administrative |
| | Interface: "/orchestrator/[component-unique- |
| | identifier]",</li><li>Component-specific |
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| | Collection topic: "/[component-unique- |
| | identifier]/collect", or</li><li>Through |
| | subscriptions such as "/collection/[collection- |
| | type]"</li></ul> |
+--------------+---------------------------------------------------+
| Source | Orchestrator |
| Component | |
+--------------+---------------------------------------------------+
| Target | Collector |
| Component(s) | |
+--------------+---------------------------------------------------+
Table 6
5.4.2.1.2. Request Payload
The request to schedule periodic collection is represented as a
wrapper of the collection instructions used to initiate ad-hoc
collection. Additional elements indicate the establishment of the
schedule, the collection schedule itself, and whether or not to
perform an immediate collection upon receipt of the payload.
periodic-collection:
collection-identifier: 12345
operation: schedule
collection-schedule:
TBD (cron formatted? other scheduling formats?)
collect-upon-acknowledgement: true/false
collection-instructions:
# Formatted per Ad-Hoc Collection taxonomy
5.4.2.1.3. Request Processing
Upon receipt of the request to establish periodic collection, the
Collector must first determine if the "collection-identifier" is
unique. If an existing periodic collection, using the same
identifier, is already present, an error payload MUST be returned to
the Orchestrator. Once the collection identifier has been validated,
the schedule is established within the scope of the Collector
receiving the instructions. If the "collect-upon-acknowledgement"
flag is set to "true", the Collector MUST perform an immediate ad-hoc
collection based on the instructions passed in the payload and the
collected posture attributes are provided to the "response-topic" per
the "collection-instructions".
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5.4.2.1.4. Response Payload
Essentially, two payloads could be provided in ##### Response
Processing
5.4.2.2. Cancel Periodic Collection
TBD
5.4.2.2.1. Interaction
+==============+===================================================+
| Property | Value |
+==============+===================================================+
| Type | Directed or Broadcast |
+--------------+---------------------------------------------------+
| Topic | <ul><li>The Orchestrator-Component Administrative |
| | Interface: "/orchestrator/[component-unique- |
| | identifier]",</li><li>Component-specific |
| | Collection topic: "/[component-unique- |
| | identifier]/collect", or</li><li>Through |
| | subscriptions such as "/collection/[collection- |
| | type]"</li></ul> |
+--------------+---------------------------------------------------+
| Source | Orchestrator |
| Component | |
+--------------+---------------------------------------------------+
| Target | Collector |
| Component(s) | |
+--------------+---------------------------------------------------+
Table 7
5.4.2.2.2. Request Payload
periodic-collection:
collection-identifier: 12345
operation: cancel
collect-upon-acknowledgement: true/false
5.4.2.2.3. Request Processing
##### Response Payload ##### Response Processing
5.4.3. Observational/Event-based
5.5. Evaluation
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5.5.1. Ad-Hoc
5.5.2. Periodic
5.5.3. Change/Event-based
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", Work in Progress,
Internet-Draft, draft-ietf-sacm-ecp-05, 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 v7.1", n.d.,
<https://www.cisecurity.org/controls>.
[draft-birkholz-sacm-yang-content]
Birkholz, H. and N. Cam-Winget, "YANG subscribed
notifications via SACM Statements", n.d.,
<https://tools.ietf.org/html/draft-birkholz-sacm-yang-
content-01>.
[HACK100] "IETF 100 Hackathon - Vulnerability Scenario EPCP+XMPP",
n.d., <https://www.github.com/sacmwg/vulnerability-
scenario/ietf-hackathon>.
[HACK101] "IETF 101 Hackathon - Configuration Assessment XMPP",
n.d., <https://www.github.com/CISecurity/Integration>.
[HACK102] "IETF 102 Hackathon - YANG Collection on Traditional
Endpoints", n.d.,
<https://www.github.com/CISecurity/YANG>.
[HACK103] "IETF 103 Hackathon - N/A", n.d.,
<https://www.ietf.org/how/meetings/103/>.
[HACK104] "IETF 104 Hackathon - A simple XMPP client", n.d.,
<https://github.com/CISecurity/SACM-Architecture>.
[HACK105] "IETF 105 Hackathon - A more robust XMPP client including
collection extensions", n.d.,
<https://github.com/CISecurity/SACM-Architecture>.
[HACK99] "IETF 99 Hackathon - Vulnerability Scenario EPCP", n.d.,
<https://www.github.com/sacmwg/vulnerability-scenario/
ietf-hackathon>.
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[I-D.ietf-sacm-terminology]
Birkholz, H., Lu, J., Strassner, J., Cam-Winget, N., and
A. Montville, "Security Automation and Continuous
Monitoring (SACM) Terminology", Work in Progress,
Internet-Draft, draft-ietf-sacm-terminology-16, 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", n.d.,
<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", n.d., <https://xmpp.org/extensions/>.
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.
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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
A.1.1.3. Workflow(s)
TBD
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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).
A.2.1. Components, Capabilities and Workflow(s)
TBD
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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
* Configuration assessment tool queries asset inventory repository
to retrieve a list of affected endpoints
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* 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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