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-05
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-
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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
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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 3
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/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. Queries . . . . . . . . . . . . . . . . . . . . . . . 16
5. Taxonomy . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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
5.1.8. Response Processing . . . . . . . . . . . . . . . . . 18
5.2. Component Registration . . . . . . . . . . . . . . . . . 18
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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 . . . . . . . . . . . . . . . . . . . . . . 18
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 . . . . . . . . . 19
5.3.2. Directed Collection . . . . . . . . . . . . . . . . . 20
5.4. [Taxonomy Name] . . . . . . . . . . . . . . . . . . . . . 20
5.4.1. Topic . . . . . . . . . . . . . . . . . . . . . . . . 21
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21
7. Security Considerations . . . . . . . . . . . . . . . . . . . 21
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
9.1. Normative References . . . . . . . . . . . . . . . . . . 21
9.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. Security Domain Workflows . . . . . . . . . . . . . 24
A.1. IT Asset Management . . . . . . . . . . . . . . . . . . . 24
A.1.1. Components, Capabilities and Workflow(s) . . . . . . 24
A.2. Vulnerability Management . . . . . . . . . . . . . . . . 25
A.2.1. Components, Capabilities and Workflow(s) . . . . . . 26
A.3. Configuration Management . . . . . . . . . . . . . . . . 26
A.3.1. Components, Capabilities and Workflow(s) . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
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].
2. Terms and Definitions
This draft defers to [I-D.ietf-sacm-terminology] for terms and
definitions.
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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.
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)
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] ### Coordinate Periodic Evaluation [TBD] #### Schedule [TBD]
#### Cancel [TBD] ### Coordinate Change-based Evaluation [TBD] i.e.
if a posture attribute in the repository is changed, trigger an
evaluation of particular policy items
4.3.6. 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
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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,
* 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.
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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"
"[component-type]" includes "pcs", "repository", "pes", and MORE TBD
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 - identifying-information -
component-type (pcs, pes, repository, etc) - name - description
5.2.5. Receiver
Orchestrator
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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.
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]"
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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 - list of topics to subscribe
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
### Directed Evaluation ### Heartbeat
5.4. [Taxonomy Name]
DESCRIPTION OF TAXONOMY
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5.4.1. Topic
"/name/of/topic" ### Interaction Type [Directed (Request/Response)
-or- Publish/Subscribe] ### Initiator [Component sending/publishing
the payload] ### Request Payload DESCRIPTION OF INFORMATION MODEL OF
REQUEST PAYLOAD; i.e. what elements need to be in whatever format in
the payload. ### Receiver [Component receiving/subscribed-to the
payload] ### Process Description [What the receiver does with the
payload] ### Response Payload DESCRIPTION OF INFORMATION MODEL OF
RESPONSE PAYLOAD; i.e. what elements need to be in whatever format in
the payload. ### 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,
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<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>.
[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/>.
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[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,
<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>.
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[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/>.
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
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* 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
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
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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
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
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* 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
* 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.
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* Configuration Assessment Results Repository: A component used for
storing evaluation results.
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.
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1. A policy feed provides a configuration assessment policy payload
to the Integration Service.
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
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Adam W. Montville
Center for Internet Security
31 Tech Valley Drive
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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