Security Automation and Continuous Monitoring (SACM) Architecture
draft-ietf-sacm-arch-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Expired".
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|---|---|---|---|
| Authors | Adam W. Montville , Bill Munyan | ||
| Last updated | 2019-07-26 (Latest revision 2019-02-22) | ||
| Replaces | draft-mandm-sacm-architecture | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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| Additional resources | Mailing list discussion | ||
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draft-ietf-sacm-arch-02
SACM Working Group A. Montville
Internet-Draft B. Munyan
Intended status: Standards Track CIS
Expires: January 27, 2020 July 26, 2019
Security Automation and Continuous Monitoring (SACM) Architecture
draft-ietf-sacm-arch-02
Abstract
This memo defines a Security Automation and Continuous Monitoring
(SACM) architecture. This work is built upon [RFC8600], and is
predicated upon information gleaned from SACM Use Cases and
Requirements ([RFC7632] and [RFC8248] respectively), and terminology
as found in [I-D.ietf-sacm-terminology].
WORKING GROUP: The source for this draft is maintained in GitHub.
Suggested changes should be submitted as pull requests at
https://github.com/sacmwg/ietf-mandm-sacm-arch/. Instructions are on
that page as well.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 27, 2020.
Copyright Notice
Copyright (c) 2019 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
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carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 3
3. Architectural Overview . . . . . . . . . . . . . . . . . . . 3
4. Relevant Workflows . . . . . . . . . . . . . . . . . . . . . 5
4.1. IT Asset Management . . . . . . . . . . . . . . . . . . . 5
4.2. Vulnerability Management . . . . . . . . . . . . . . . . 5
4.3. Configuration Management . . . . . . . . . . . . . . . . 6
5. Configuration Management Components, Interactions, and
Capabilities . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Components . . . . . . . . . . . . . . . . . . . . . . . 7
5.2. Interactions . . . . . . . . . . . . . . . . . . . . . . 8
5.3. Capabilities . . . . . . . . . . . . . . . . . . . . . . 8
6. Configuration Assessment Workflow . . . . . . . . . . . . . . 9
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
10.1. Normative References . . . . . . . . . . . . . . . . . . 11
10.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Mapping to RFC8248 . . . . . . . . . . . . . . . . . 13
Appendix B. Example Components . . . . . . . . . . . . . . . . . 16
B.1. Policy Services . . . . . . . . . . . . . . . . . . . . . 16
B.2. Software Inventory . . . . . . . . . . . . . . . . . . . 17
B.3. Datastream Collection . . . . . . . . . . . . . . . . . . 18
B.4. Network Configuration Collection . . . . . . . . . . . . 18
Appendix C. Exploring An XMPP-based Solution . . . . . . . . . . 19
C.1. Example Architecture using XMPP-Grid and Endpoint Posture
Collection Protocol . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction
The purpose of this draft is to define an architectural approach for
a SACM Domain, based on the spirit of use cases found in [RFC7632]
and requirements found in [RFC8248]. This approach gains the most
advantage by supporting a variety of collection systems, and intends
to enable a cooperative ecosystem of tools from disparate sources
with minimal operator configuration.
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1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119, BCP 14 [RFC2119].
2. Terms and Definitions
This draft defers to [I-D.ietf-sacm-terminology] for terms and
definitions.
3. Architectural Overview
The generic approach proposed herein recognizes the need to obtain
information from existing and future state collection systems, and
makes every attempt to respect [RFC7632] and [RFC8248]. At the
foundation of any architecture are entities, or components, that need
to communicate. They communicate by sharing information, where, in a
given flow, one or more components are consumers of information and
one or more components are providers of information.
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+--------------------+
| Feeds/Repositories |
| of External Data |
+--------------------+
|
|
*****************************v**************** Enterprise Boundary ************
* | *
* +---------------+ | +--------------+ *
* | Orchestrators | | | Repositories | *
* +------^--------+ | +----^---------+ *
* | | | +----------------+ *
* | | | | Downstream Uses| *
* | | | | +-----------+ | *
* +------v------------------v----------v------+ | |Evaluations| | *
* | Message Transfer System <-------> +-----------+ | *
* +----------------------^--------------------+ | +-----------+ | *
* | | | Analytics | | *
* | | +-----------+ | *
* +-------------v------+ | +-----------+ | *
* | Collection Systems | | | Reporting | | *
* +--------------------+ | +-----------+ | *
* +----------------+ *
*******************************************************************************
Figure 1: Notional Architecture
As shown in Figure 1, the notional SACM architecture consists of some
basic SACM Components using a message transfer system to communicate.
The message transfer system is expected to maximally align with the
requirements described in [RFC8248], which means that the message
transfer system will support brokered (i.e. point-to-point) and
proxied data exchange.
The enterprise boundary is not intended to imply a physical boundary.
Rather, the enterprise boundary is intended to be inclusive of
various cloud environments and vendor-provided services in addition
to any physical systems the enterprise operates.
This document suggests a variety of players in a cooperative
ecosystem - we call these players 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.
Generally each role is either a consumer of information or a provider
of information.
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4. Relevant Workflows
This section describes three primary information security domains
from which workflows may be derived: IT Asset Management,
Vulnerability Management, and Configuration Management.
4.1. 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.
An IT asset management capability needs to be able to:
o Identify and catalog new assets by executing Target Endpoint
Discovery Tasks
o Provide information about its managed assets, including uniquely
identifying information (for that enterprise)
o Handle software and/or hardware (including virtual assets)
o Represent cloud hybrid environments
4.2. 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:
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o Endpoint information collected by the endpoint management
capabilities is examined by the vulnerability management
capabilities through Evaluation Tasks.
o 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:
o A specific software version is installed on the endpoint
o File system attributes
o 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).
4.3. 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
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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:
o Reputable source publishes new or updated configuration guidance
o Enterprise configuration assessment capability retrieves
configuration guidance from reputable source
o Optional: Configuration guidance is tailored for enterprise-
specific needs
o Configuration assessment tool queries asset inventory repository
to retrieve a list of affected endpoints
o Configuration assessment tool queries configuration state
repository to evaluate compliance
o 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.
5. Configuration Management Components, Interactions, and Capabilities
This section provides more detail about the components, interactions,
and capabilities required when considering the aforementioned
configuration management workflow.
5.1. Components
The following is a minimal list of SACM Components required to
implement the aforementioned configuration assessment workflow.
o Configuration Policy Feed: An external source of authoritative
configuration recommendations.
o Configuration Policy Repository: An internal repository of
enterprise standard configurations.
o Configuration Assessment Orchestrator: A component responsible for
orchestrating assessments.
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o Posture Attribute Collection Subsystem: A component responsible
for collection of posture attributes from systems.
o Posture Attribute Repository: A component used for storing system
posture attribute values.
o Configuration Assessment Evaluator: A component responsible for
evaluating system posture attribute values against expected
posture attribute values.
o Configuration Assessment Results Repository: A component used for
storing evaluation results.
5.2. Interactions
SACM Components are intended to interact with other SACM Components.
These interactions can be thought of, at the level of this
architectural approach, as the combination of interfaces with their
supported operations.
o Store: One component stores information in another.
o Ask: A component requests information from another.
o Notify/Ask: A component notifies another component, which then
asks the notifying component (or another component) for
information.
o Publish/Subscribe: A component publishes information to a
messaging system and a set of other components, subscribed to that
information type, receive the published information.
o Tell: A component instructs another.
TODO: Consider breaking out Notify, Publish, and Subscribe into
separate line items, and adding Error (a type of Notify). Then
consider explaining the necessary combinations relevant to the
configuration assessment workflow below.
Each interaction will convey a payload of information. The payload
information is expected to contain sub-domain-specific
characteristics and instructions.
5.3. 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
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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".
6. 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 |
+-----+-------+
| 5.1
1 | +----------------------------------------+
| | |
+-----v------+ 2 +----------------+ 5 +-----v-----+ 6 +------------+
| Policy +------> Orchestrator +-----> Evaluator +------> Evaluation |
| Repository | +-------+--------+ +-----^-----+ | Results |
+------------+ | | | Repository |
| 3 | +------------+
| | 5.2
+----------|--------+ |
| +--------v------+ | |
| | Collector | | |
| +-------+-------+ | 4 +------------+
| | +-------> Posture |
| +-------+-------+ | | Attribute |
| | Target System | | | Repository |
| +---------------+ | +------------+
+-------------------+
Collection Sub-Architecture
Figure 2: Configuration Assessment Component Interactions
Figure 2 depicts configuration assessment components and their
interactions, which are further described below.
1. Policy is stored in the Policy Repository: TODO - add specific
interaction options here.
2. The Orchestrator obtains collection information from the Policy
Repository: TODO - add specific interaction options here.
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3. The Orchestrator initiates collection to be performed by the
Collection Sub-Architecture: TODO - add specific interaction
options here.
4. Collected posture attributes are stored n the Posture Attribute
Repository: TODO - add specific interaction options here.
5. The Orchestrator initiates the Evaluator (optionally with
evaluation information gathered from the Policy Repository): TODO
- add specific interaction options here
1. The Evaluator obtains evaluation information from the Policy
Repository (optionally): TODO - add specific interaction
options here
2. The Evaluator obtains relevant posture attributes from the
Posture Attribute Repository: TODO - add specific interaction
options here
6. Evaluation results are stored in the Evaluation Results
Repository: TODO - add specific interaction options here
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, the Tell 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.
7. Privacy Considerations
TODO
8. Security Considerations
TODO
9. IANA Considerations
TODO: 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:
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o Capability/operation semantics
o SACM Component implementation identifiers
o SACM Component versions
o Associations of SACM Components (and versions) to specific
Capabilities
o Collection sub-architecture Identification
10. References
10.1. 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), June 2019.
[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>.
10.2. Informative References
[CISCONTROLS]
"CIS Controls v7.0", 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>.
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[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/IETF104-Client>.
[HACK105] "IETF 105 Hackathon - A more robust XMPP client including
collection extensions", n.d.,
<https://github.com/CISecurity/IETF104-Client>.
[HACK99] "IETF 99 Hackathon - Vulnerability Scenario EPCP", n.d.,
<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), December 2018.
[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>.
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[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. Mapping to RFC8248
TODO: Consider removing or placing in a separate solution draft.
This section provides a mapping of XMPP and XMPP Extensions to the
relevant requirements from [RFC8248]. In the table below, the ID and
Name columns provide the ID and Name of the requirement directly out
of [RFC8248]. The Supported By column may contain one of several
values:
o N/A: The requirement is not applicable to this architectural
exploration
o Architecture: This architecture (possibly assuming some
components) should meet the requirement
o XMPP: The set of XMPP Core specifications and the collection of
applicable extensions, deployment, and operational considerations.
o XMPP-Core: The requirement is satisfied by a core XMPP feature
o XEP-nnnn: The requirement is satisfied by a numbered XMPP
extension (see [XMPPEXT])
o Operational: The requirement is an operational concern or can be
addressed by an operational deployment
o Implementation: The requirement is an implementation concern
If there is no entry in the Supported By column, then there is a gap
that must be filled.
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+----------+----------------------------------------+---------------+
| ID | Name | Supported By |
+----------+----------------------------------------+---------------+
| G-001 | Solution Extensibility | XMPP-Core |
| | | |
| G-002 | Interoperability | XMPP |
| | | |
| G-003 | Scalability | XMPP |
| | | |
| G-004 | Versatility | XMPP-Core |
| | | |
| G-005 | Information Extensibility | XMPP-Core |
| | | |
| G-006 | Data Protection | Operational |
| | | |
| G-007 | Data Partitioning | Operational |
| | | |
| G-008 | Versioning and Backward Compatibility | XEP-0115/0030 |
| | | |
| G-009 | Information Discovery | XEP-0030 |
| | | |
| G-010 | Target Endpoint Discovery | XMPP-Core |
| | | |
| G-011 | Push and Pull Access | XEP-0060/0312 |
| | | |
| G-012 | SACM Component Interface | N/A |
| | | |
| G-013 | Endpoint Location and Network Topology | |
| | | |
| G-014 | Target Endpoint Identity | XMPP-Core |
| | | |
| G-015 | Data Access Control | |
| | | |
| ARCH-001 | Component Functions | XMPP |
| | | |
| ARCH-002 | Scalability | XMPP-Core |
| | | |
| ARCH-003 | Flexibility | XMPP-Core |
| | | |
| ARCH-004 | Separation of Data and Management | |
| | Functions | |
| | | |
| ARCH-005 | Topology Flexibility | XMPP-Core |
| | | |
| ARCH-006 | Capability Negotiation | XEP-0115/0030 |
| | | |
| ARCH-007 | Role-Based Authorization | XMPP-Core |
| | | |
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| ARCH-008 | Context-Based Authorization | |
| | | |
| ARCH-009 | Time Synchronization | Operational |
| | | |
| IM-001 | Extensible Attribute Vocabulary | N/A |
| | | |
| IM-002 | Posture Data Publication | N/A |
| | | |
| IM-003 | Data Model Negotiation | N/A |
| | | |
| IM-004 | Data Model Identification | N/A |
| | | |
| IM-005 | Data Lifetime Management | N/A |
| | | |
| IM-006 | Singularity and Modularity | N/A |
| | | |
| DM-001 | Element Association | N/A |
| | | |
| DM-002 | Data Model Structure | N/A |
| | | |
| DM-003 | Search Flexibility | N/A |
| | | |
| DM-004 | Full vs. Partial Updates | N/A |
| | | |
| DM-005 | Loose Coupling | N/A |
| | | |
| DM-006 | Data Cardinality | N/A |
| | | |
| DM-007 | Data Model Negotiation | N/A |
| | | |
| DM-008 | Data Origin | N/A |
| | | |
| DM-009 | Origination Time | N/A |
| | | |
| DM-010 | Data Generation | N/A |
| | | |
| DM-011 | Data Source | N/A |
| | | |
| DM-012 | Data Updates | N/A |
| | | |
| DM-013 | Multiple Collectors | N/A |
| | | |
| DM-014 | Attribute Extensibility | N/A |
| | | |
| DM-015 | Solicited vs. Unsolicited Updates | N/A |
| | | |
| DM-016 | Transfer Agnostic | N/A |
| | | |
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| OP-001 | Time Synchronization | |
| | | |
| OP-002 | Collection Abstraction | |
| | | |
| OP-003 | Collection Composition | |
| | | |
| OP-004 | Attribute-Based Query | |
| | | |
| OP-005 | Information-Based Query with Filtering | |
| | | |
| OP-006 | Operation Scalability | |
| | | |
| OP-007 | Data Abstraction | |
| | | |
| OP-008 | Provider Restriction | |
| | | |
| T-001 | Multiple Transfer Protocol Support | Architecture |
| | | |
| T-002 | Data Integrity | Operational |
| | | |
| T-003 | Data Confidentiality | Operational |
| | | |
| T-004 | Transfer Protection | |
| | | |
| T-005 | Transfer Reliability | |
| | | |
| T-006 | Transfer-Layer Requirements | |
| | | |
| T-007 | Transfer Protocol Adoption | Architecture |
+----------+----------------------------------------+---------------+
Appendix B. Example Components
TODO: Consider removing.
B.1. Policy Services
Consider a policy server conforming to [RFC8322]. [RFC8322]
describes a RESTful way based on the ATOM Publishing Protocol
([RFC5023]) to find specific data collections. While this represents
a specific binding (i.e. RESTful API based on [RFC5023]), there is a
more abstract way to look at ROLIE.
ROLIE provides notional workspaces and collections, and provides the
concept of information categories and links. Strictly speaking,
these are logical concepts independent of the RESTful binding ROLIE
specifies. In other words, ROLIE binds a logical interface (i.e.
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GET workspace, GET collection, SET entry, and so on) to a specific
mechanism (namely an ATOM Publication Protocol extension).
It is not inconceivable to believe there could be a different
interface mechanism, or a connector, providing these same operations
using XMPP-Grid as the transfer mechanism.
Even if a [RFC8322] server were external to an organization, there
would be a need for a policy source inside the organization as well,
and it may be preferred for such a policy source to be connected
directly to the ecosystem's communication infrastructure.
B.2. Software Inventory
The SACM working group has accepted work on the Endpoint Posture
Collection Profile [I-D.ietf-sacm-ecp], which describes a collection
architecture and may be viewed as a collector coupled with a
collection-specific repository.
Posture Manager Endpoint
Orchestrator +---------------+ +---------------+
+--------+ | | | |
| | | +-----------+ | | +-----------+ |
| |<---->| | Posture | | | | Posture | |
| | pub/ | | Validator | | | | Collector | |
| | sub | +-----------+ | | +-----------+ |
+--------+ | | | | | |
| | | | | |
Evaluator Repository | | | | | |
+------+ +--------+ | +-----------+ |<-------| +-----------+ |
| | | | | | Posture | | report | | Posture | |
| | | | | | Collection| | | | Collection| |
| |<-----> | |<-----| | Manager | | query | | Engine | |
| |request/| | store| +-----------+ |------->| +-----------+ |
| |respond | | | | | |
| | | | | | | |
+------+ +--------+ +---------------+ +---------------+
Figure 3: EPCP Collection Architecture
In Figure 3, any of the communications between the Posture Manager
and EPCP components to its left could be performed directly or
indirectly using a given message transfer mechanism. For example,
the pub/sub interface between the Orchestrator and the Posture
Manager could be using a proprietary method or using [RFC8600] or
some other pub/sub mechanism. Similarly, the store connection from
the Posture Manager to the Repository could be performed internally
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to a given implementation, via a RESTful API invocation over HTTPS,
or even over a pub/sub mechanism.
Our assertion is that the Evaluator, Repository, Orchestrator, and
Posture Manager all have the potential to represent SACM Components
with specific capability interfaces that can be logically specified,
then bound to one or more specific transfer mechanisms (i.e. RESTful
API, [RFC8322], [RFC8600], and so on).
B.3. Datastream Collection
[NIST800126], also known as SCAP 1.3, provides the technical
specifications for a "datastream collection". The specification
describes the "datastream collection" as being "composed of SCAP data
streams and SCAP source components". A "datastream" provides an
encapsulation of the SCAP source components required to, for example,
perform configuration assessment on a given endpoint. These source
components include XCCDF checklists, OVAL Definitions, and CPE
Dictionary information. A single "datastream collection" may
encapsulate multiple "datastreams", and reference any number of SCAP
components. Datastream collections were intended to provide an
envelope enabling transfer of SCAP data more easily.
The [NIST800126] specification also defines the "SCAP result data
stream" as being conformant to the Asset Reporting Format
specification, defined in [NISTIR7694]. The Asset Reporting Format
provides an encapsulation of the SCAP source components, Asset
Information, and SCAP result components, such as system
characteristics and state evaluation results.
What [NIST800126]did not do is specify the interface for finding or
acquiring source datastream information, nor an interface for
publishing result information. Discovering the actual resources for
this information could be done via ROLIE, as described in the Policy
Services section above, but other repositories of SCAP data exist as
well.
B.4. Network Configuration Collection
[draft-birkholz-sacm-yang-content] illustrates a SACM Component
incorporating a YANG Push client function and an XMPP-grid publisher
function. [draft-birkholz-sacm-yang-content] further states "the
output of the YANG Push client function is encapsulated in a SACM
Content Element envelope, which is again encapsulated in a SACM
statement envelope" which are published, essentially, via an XMPP-
Grid Connector for SACM Components also part of the XMPP-Grid.
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This is a specific example of an existing collection mechanism being
adapted to the XMPP-Grid message transfer system.
Appendix C. Exploring An XMPP-based Solution
TODO: Consider removing or placing in a separate draft.
Ongoing work has been taking place around and during IETF hackathons.
The list of hackathon efforts follows:
o [HACK99]: A partial implementation of a vulnerability assessment
scenario involving an [I-D.ietf-sacm-ecp] implementation, a
[RFC8322] implementation, and a proprietary evaluator to pull the
pieces together.
o [HACK100]: Work to combine the vulnerability assessment scenario
from [HACK99] with an XMPP-based YANG push model.
o [HACK101]: A fully automated configuration assessment
implementation using XMPP (specifically Publish/Subscribe
capabilities) as a communication mechanism.
o [HACK102]: An exploration of how we might model assessment,
collection, and evaluation abstractly, and then rely on YANG
expressions for the attributes of traditional endpoints.
o [HACK103]: No SACM participation at the Bangkok hackathon.
o [HACK104]: Basic XMPP-to-Concise MAP - Created an XMPP adapter
that can accept basic posture attributes and translate them to
Concise MAP. This hackathon only proved the concept that system
characteristics information can be transported via XMPP and
translated to a (very basic) concise MAP implementation.
o [HACK105]: Advanced XMPP-to-Concise MAP: Full orchestration of
collection capabilities using XMPP. Collector implementations
extend the core XMPP structure to allow OVAL collection
instructions (OVAL objects) to inform posture attribute
collection. Collected system characteristics can be provided to
the Concise MAP XMPP adapter using all 3 available XMPP
capabilities: Publish/Subscribe, Information Query (iq - request/
response) stanzas, or direct Message stanzas. CDDL was created to
map collected posture attributes to Concise MAP structure. The
XMPP adapter translates the incoming system characteristics and
stores the information in the MAP.
Figure 4 depicts a slightly more detailed view of the architecture
(within the enterprise boundary) - one that fosters the development
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of a pluggable ecosystem of cooperative tools. Existing collection
mechanisms can be brought into this architecture by specifying the
interface of the collector and creating the XMPP-Grid Connector
binding for that interface.
Additionally, while not directly depicted in Figure 4, this
architecture does allow point-to-point interfaces. In fact,
[RFC8600] provides brokering capabilities to facilitate such point-
to-point data transfers). Additionally, each of the SACM Components
depicted in Figure 4 may be a provider, a consumer, or both,
depending on the workflow in context.
+--------------+ +--------------+
| Orchestrator | | Repositories |
+------^-------+ +------^-------+
| |
| |
+-------v--------------------------v--------+ +-----------------+
| XMPP-Grid+ <-----> Downstream Uses |
+------------------------^------------------+ +-----------------+
|
|
+-------v------+
| XMPP-Grid |
| Connector(s) |
+------^-------+
|
+------v-------+
| Collector(s) |
+--------------+
Figure 4: XMPP-based Architecture
[RFC8600] details a number of XMPP extensions (XEPs) that MUST be
utilized to meet the needs of [RFC7632] and [RFC8248]:
o Service Discovery (XEP-0030): Service Discovery allows XMPP
entities to discover information about other XMPP entities. Two
kinds of information can be discovered: the identity and
capabilities of an entity, such as supported features, and items
associated with an entity.
o Publish-Subscribe (XEP-0060): The PubSub extension enables
entities to create nodes (topics) at a PubSub service and publish
information at those nodes. Once published, an event notification
is broadcast to all entities that have subscribed to that node.
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At this point, [RFC8600] specifies fewer features than SACM requires,
and there are other XMPP extensions (XEPs) we need to consider to
meet the needs of [RFC7632] and [RFC8248]. In Figure 4 we therefore
use "XMPP-Grid+" to indicate something more than [RFC8600] alone,
even though we are not yet fully confident in the exact set of XMPP-
related extensions we will require. The authors propose work to
extend (or modify) [RFC8600] to include additional XEPs - possibly
the following:
o Entity Capabilities (XEP-0115): This extension defines the methods
for broadcasting and dynamically discovering an entities'
capabilities. This information is transported via standard XMPP
presence. Example capabilities that could be discovered could
include support for posture attribute collection, support for
specific types of posture attribute collection such as EPCP,
SWIMA, OVAL, or YANG. Other capabilities are still to be
determined.
o Ad Hoc Commands (XEP-0050): This extension allows an XMPP entity
to advertise and execute application-specific commands. Typically
the commands contain data forms (XEP-0004) in order to structure
the information exchange. This extension may be usable for simple
orchestration (i.e. "do assessment").
o HTTP File Upload (XEP-0363): The HTTP File Upload extension allows
for large data sets to be published to a specific path on an HTTP
server, and receive a URL from which that file can later be
downloaded again. XMPP messages and IQs are meant to be compact,
and large data sets, such as collected posture attributes, may
exceed a message size threshold. Usage of this XEP allows those
larger data sets to be persisted, thus necessitating only the
download URL to be passed via XMPP messages.
o Personal Eventing Protocol (XEP-0163): The Personal Eventing
Protocol can be thought of as a virtual PubSub service, allowing
an XMPP account to publish events only to their roster instead of
a generic PubSub topic. This XEP may be useful in the cases when
collection requests or queries are only intended for a subset of
endpoints and not an entire subscriber set.
o File Repository and Sharing (XEP-0214): This extension defines a
method for XMPP entities to designate a set of file available for
retrieval by other users of their choosing, and is based on PubSub
Collections.
o Easy User Onboarding (XEP-401): The goal of this extension is
simplified client registration, and may be useful when adding new
endpoints or SACM components to the ecosystem.
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o Bidirectional-streams Over Synchronous HTTP (BOSH) (XEP-0124):
BOSH emulates the semantics of a long-lived, bidirectional TCP
connection between two entities (aka "long polling"). Consider a
SACM component that is updated dynamically, i.e. an internal
vulnerability definition repository ingesting data from a Feed/
Repository of External Data, and a second SACM component such as
an Orchestrator. Using BOSH, the Orchestrator can effectively
continuously poll the vulnerability definition repository for
changes/updates.
o PubSub Collection Nodes (XEP-0248): Effectively an extension to
XEP-0060 (Publish-Subscribe), PubSub Collections aim to simplify
an entities' subscription to multiple related topics, and
establishes a "node graph" relating parent nodes to its
descendents. An example "node graph" could be rooted in a
"vulnerability definitions" topic, and contain descendent topics
for OS family-level vulnerability definitions (i.e. Windows), and
further for OS family version-level definitions (i.e. Windows 10
or Windows Server 2016).
o PubSub Since (XEP-0312): This extension enables a subscriber to
automatically receive PubSub and Personal Eventing Protocol (PEP)
notifications since its last logout time. This extension may be
useful in intermittent connection scenarios, or when entities
disconnect and reconnect to the ecosystem.
o PubSub Chaining (XEP-0253): This extension describes the
federation of publishing nodes, enabling a publish node of one
server to be a subscriber to a publishing node of another server.
C.1. Example Architecture using XMPP-Grid and Endpoint Posture
Collection Protocol
Figure 5 depicts a further detailed view of the architecture
including the Endpoint Posture Collection Protocol as the collection
subsystem, illustrating the idea of a pluggable ecosystem of
cooperative tools.
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+--------------------+
| Feeds/Repositories |
| of External Data |
+--------------------+
|
********************v************************* Enterprise Boundary ************
* | *
* +--------------+ | +-------------------+ +-------------+ *
* | Orchestrator | | | Posture Attr Repo | | Policy Repo | *
* +------^-------+ | +---------^---------+ +---^---------+ *
* | | | | +----------------+ *
* | | | | | Downstream Uses| *
* | | | | | +-----------+ | *
* +------v---------v-----------v---------------v--+ | |Evaluations| | *
* | XMPP-Grid <-------> +-----------+ | *
* +----------------^-------------------^----------+ | +-----------+ | *
* | | | | Analytics | | *
* | | | +-----------+ | *
* | +-----v--------+ | +-----------+ | *
* | | Results Repo | | | Reporting | | *
* | +--------------+ | +-----------+ | *
* | +----------------+ *
* +---------v-----------+ *
* | XMPP-Grid Connector | *
* +---------^-----------+ *
* | *
* +-----------------v-------------------------------------------------------+ *
* | | *
* | +--Posture Collection Manager------------------------------------------+| *
* | |+-----------------------+ +----------------+ +----------------------+ || *
* | || Communications Server | | Posture Server | | Posture Validator(s) | || *
* | |+----------^------------+ +----------------+ +----------------------+ || *
* | +-----------|----------------------------------------------------------+| *
* | | | *
* | +-----------|-------------------------Endpoint or Endpoint Proxy-------+| *
* | |+----------v------------+ +----------------+ +----------------------+ || *
* | || Communications Client | | Posture Client | | Posture Collector(s) | || *
* | |+-----------------------+ +----------------+ +----------------------+ || *
* | +----------------------------------------------------------------------+| *
* +-----------------Endpoint Posture Collection Profile---------------------+ *
* *
*******************************************************************************
Figure 5: XMPP-based Architecture including EPCP
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Authors' Addresses
Adam W. Montville
Center for Internet Security
31 Tech Valley Drive
East Greenbush, NY 12061
USA
Email: adam.montville.sdo@gmail.com
Bill Munyan
Center for Internet Security
31 Tech Valley Drive
East Greenbush, NY 12061
USA
Email: bill.munyan.ietf@gmail.com
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