Secure Automation and Continuous Monitoring (SACM) Requirements
draft-ietf-sacm-requirements-03
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| Document | Type | Active Internet-Draft (sacm WG) | |
|---|---|---|---|
| Authors | Nancy Cam-Winget , Lisa Lorenzin | ||
| Last updated | 2015-01-03 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-sacm-requirements-03
SACM N. Cam-Winget
Internet-Draft Cisco Systems
Intended status: Informational L. Lorenzin
Expires: July 6, 2015 Pulse Secure
January 2, 2015
Secure Automation and Continuous Monitoring (SACM) Requirements
draft-ietf-sacm-requirements-03
Abstract
This document defines the scope and set of requirements for the
Secure Automation and Continuous Monitoring working group. The
requirements and scope are based on the agreed upon use cases.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 6, 2015.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Requirements for SACM . . . . . . . . . . . . . . . . . . 3
2.2. Requirements for the Architecture . . . . . . . . . . . . 5
2.3. Requirements for the Data Model . . . . . . . . . . . . . 6
2.4. Requirements for Transport Protocols . . . . . . . . . . 9
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5.1. Trust between Provider and Requestor . . . . . . . . . . 10
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
Today's environment of rapidly-evolving security threats highlights
the need to automate the sharing of such information while protecting
user information as well as the systems that store, process, and
transmit this information. Security threats can be detected in a
number of ways. SACM's charter focuses on how to collect and share
this information based on use cases that involve posture assessment
of endpoints.
Scalable and sustainable collection, expression, and evaluation of
endpoint information is foundational to SACM's objectives. To secure
and defend a network one must reliably determine what devices are on
the network, how those devices are configured from a hardware
perspective, what software products are installed on those devices,
and how those products are configured. We need to be able to
determine, share, and use this information in a secure, timely,
consistent, and automated manner to perform endpoint posture
assessments.
This document focuses on describing the requirements for facilitating
the exchange of posture assessment information, in particular, for
the use cases as exemplified in [I-D.ietf-sacm-use-cases].Also, this
document uses terminology defined in [I-D.ietf-sacm-terminology].
2. Requirements
This document defines requirements based on the SACM use cases
defined in [I-D.ietf-sacm-use-cases]. This section describes the
requirements used by SACM to assess and compare candidate data
models, their interfaces and protocols to suit the SACM architecture.
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These requirements express characteristics or features that a
candidate protocol or data model must be capable of offering to
ensure security and interoperability.
In order to address the needs for determining, sharing and using
posture information, the following tasks should be considered:
1. Define the assets. This is what we want to know about an asset.
For instance, organizations will want to know what software is
installed and its many critical security attributes such as patch
level.
2. Resolve what assets actually compose an endpoint. This requires
populating the data elements and attributes needed to exchange
information pertaining to the assets composing an endpoint.
3. Determine the expected values for the data elements and
attributes that need to be evaluated against the actual collected
instances of asset data. This is how an organization can express
its policy for an acceptable data element or attribute value. A
system administrator can also identify specific data elements and
attributes that represent problems, such as vulnerabilities, that
need to be detected on an endpoint.
4. Evaluate the collected instances of the asset data against those
expressed in the policy.
5. Report the results of the evaluation.
2.1. Requirements for SACM
Many deployment scenarios can be instantiated to address the above
tasks and use cases defined in [I-D.ietf-sacm-use-cases]. To ensure
interoperability, scalability and flexibility in any of these
deployments, the following requirements are defined for proposed SACM
standards:
G-001 Solution Extensibility: The data models, protocols and
transports defined by SACM MUST be extensible to allow support for
non-standard and future extensions.
1. The transport protocol MUST support the ability to add new
operations while maintaining backwards compatibility.
2. The query language must allow general inquiries as well as
expression of specific paths to follow; retrieval of specific
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information based on an event, as well as on a continuous basis;
and the ability to retrieve specific pieces of information,
specific types or classes of information, and/or the entirety of
available information.
3. The information model must accommodate the addition of new data
types and/or schemas in a backwards compatible fashion.
G-002 Interoperability: The data models, protocols and transports
must be specified with enough details to ensure interoperability.
G-003 Scalability: The data models, protocols and transports must be
scalable. SACM must support a broad set of deployment scenarios.
As such, it is possible that the size of posture assessment
information can vary from a single assessment that is small in
(record or datagram) size to a very large datagram or a very large
set of assessments. This must be defined by the SACM
specifications.
G-004 Agility: The agility requirement is to ensure that the data
model, protocols, and transports are suitably specified to enable
implementions to fit into the different deployment models and
scenarios. Considerations for lightweight implementations of data
models and transports is required.
G-005 Information Extensibility: A method for expressing both
standard and non-standard (implemention-specific) data attributes
while avoiding collisions SHOULD be defined. For interoperability
and scope boundary, an explicit set of data attributes MUST be
defined mandatory to implement.
G-006 Data Integrity: A method for ensuring data integrity MUST be
provided. This method is required to be available (i.e. all data-
handling components must support it), but is not required to be used
in all cases.
G-007 Data Isolation: A method for partitioning data MUST be
supported, to accommodate considerations such as geographic,
regulatory, overlay boundaries and federation, where an organization
may want to differentiate between information that can be shared
outside its own domain and information that cannot. As with the
requirement for data integrity, this method is required to be
available (i.e. all data-handling components must support it), but
is not required to be used in all cases.
G-008 Versioning and Backward Compatibility: Announcement and
negotiation of versions, inclusive of exisiting capabilities (such
as transport protocols, data models, specific attributes within data
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models, standard attribute expression sets, etc.) MUST be
supported. Negotiation for both versioning and capability is needed
to accommodate future growth and ecosystems with mixed capabilities.
G-009 Discovery: There must be a mechanism for components to
discover what information is available across the ecosystem (i.e. a
method for cataloging data available in the ecosystem and
advertising it to consumers), and where to go to get a specific
piece of that information. For example, providing a method by which
a node can locate the advertised information so that consumers are
not required to have a priori knowledge to find available
information.
G-010 Endpoint Discovery: SACM MUST define the means by which
endpoints may be discovered. Use Case 2.1.2 describes the need to
discover endpoints and their composition.
G-011 Unsolicited publication, updates or change modifications with
filtering: Use Cases 2.1.3, 2.1.4 and 2.1.5 describe the need for
the data model to support the means for the information to be
published unsolicited. Similarly, the data model must support the
means for a requestor to obtain updates or change modifications
without constant querying (or polling). Like the query operation,
these update notifications can be set up with a filter to allow for
only a subset of posture assessment information to be obtained.
2.2. Requirements for the Architecture
At the simplest abstraction, the SACM architecture represents the
core components and interfaces needed to perform the production and
consumption of posture assessment information. Requirements relating
the SACM's architecture include:
ARCH-001 Scalability: The architectural components must account for
a range of deployments, from very small set of endpoints are used to
very large deployments.
ARCH-002 Agility: The architectural components must account for
different deployment scenarios where the architectural components
may be implemented, deployed or used within a single application,
service, network or may comprise a federated system.
ARCH-003 Separation of Data and Management functions: SACM must
define both the configuration and management of the SACM data models
and protocols used to transport and share posture assessment
information.
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ARCH-004 Topology Flexibility: Both centralized and decentralized
(peer-to-peer) information exchange must be supported. Centralized
data exchange enables use of a common data format to bridge together
data exchange between diverse systems, and can leverage a virtual
data store that centralizes and offloads all data access, storage,
and maintenance to a dedicated resource. Decentralized data
exchange enables simplicity of sharing data between relatively
uniform systems, and between small numbers of systems, especially
within a single enterprise domain.
ARCH-005 Modularity: Announcement and negotiation of functional
capabilities (such as authentication protocols, authorization
schemes, data models, transport protocols, etc.) must be supported,
enabling a SACM component to make inquiries about the capabilities
of other components in the SACM ecosystem.
ARCH-006 Role based Authorization: The SACM architecture MUST be
capable of affecting role based authorization. Distinction of
endpoints capable and authorized to provide or consume information
is required to address appropriate access controls.
ARCH-007 Context based Authorization: The SACM architecture MUST be
capable of affecting a context based authorization. Different
policies (e.g. business, regulatory, etc) may specify what data may
be exposed or shared by particular consumers as well as how
consumers may be required to share the information. The context
defines the composite set of guidelines provided by policy for
affecting what posture data is allowed to be communicated from
providers to consumers.
2.3. Requirements for the Data Model
The SACM information model represents an abstraction for "what"
information can be communicated and "how" it is to be represented and
shared.
It is expected that as applications may produce Posture assessment
information, they may share it using a specific data model.
Similarly, applications consuming or requesting Posture Assessment
information, may require it be based on a specific data model. Thus,
while there may exist different data models and schemas, they should
adhere to a SACM information model that meets the requirements
defined in this section.
The specific requirements for candidate data models include:
IM-001 The data model MUST define the data attributes as objects
that MUST be uniquely referenced (e.g. endpoint, IP address, asset).
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IM-002 The data model may be structured into modules and submodules
to allow for data references within a module. For example, an
endpoint may be defined as a module that references one or more
submodules that further describe the one or more assets.
Constraints and interfaces may further be defined to resolve or
tolerate ambiguity in the references (e.g. same IP address used in
two separate networks).
IM-003 The interfaces and actions in the data model MUST include
support for rootless searches and wildcard searches
IM-004 The search interfaces and actions MUST include the ability to
start a search anywhere within a data model structure.
IM-005 The data model SHOULD include management of the data,
including data lifetime management (longevity or expiration of
data).
IM-006 Ephemerality: The information model SHOULD include the
ability to allow providers of data to provide the data as a whole or
when updates occur. The data may be provided by a requestor either
solicited or unsolicited.
IM-007 The data model SHOULD allow for a loose coupling between the
provider and the requestor.
IM-008 The interfaces and actions in the data model MUST include the
ability to identify data from a specific provider.
IM-009 Data cardinality: The data model MUST describe their
constraints (e.g. cardinality). As Posture information and the
tasks for collection, aggregation or evaluation could comprise one
or more attributes, interfaces and actions must allow and account
for such cardinality as well as whether the attributes are
conditional, optional or mandatory.
IM-010 Data model negotiation: The interfaces and actions in the
information model MUST include capability negotiation to enable
discovery of supported and available data types and schemas.
IM-011 The data model SHOULD include the ability for providers to
identify the data origin.
IM-012 Synchronization: Request and response operations SHOULD be
timestamped, and published information SHOULD capture time of
publication. Actions or decisions based on time-sensitive data
(such as user logon/logoff, endpoint connection/disconnection,
endpoint behavior events, etc.) are all predicated on a synchronized
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understanding of time. A method for detecting and reporting time
discrepancies SHOULD be provided.
IM-013 Collection separation: The request for a data item must
include enough information to properly identify the item to collect,
but the request shall not be a command to directly execute nor
directly be applied as arguments to a command. The purpose of this
requirement is primarily to reduce the potential attack vectors, but
has the additional benefit of abstracting the request for collection
from the collection method thereby allowing more flexibility in how
collection is implemented.
IM-014 Collection composition: A collection request can be composed
of multiple collection requests (which yield collected values).
This must be able to be expressed as part of the collection request
so that the aggregation can be resolved at the point of collection
without having to interact with the requester.
IM-015 Attribute based query: Use Case 2.1.2 describes the need for
the data model to support a query operation based on a set of
attributes to facilitate collection of information such as posture
assessment, inventory (of endpoints or endpoint components) and
configuration checklist.
IM-016 Information based query with filtering: Use Case 2.1.3
describes the need for the data model to support the means for the
information to be collected through a query mechanism. Furthermore,
the query operation requires filtering capabilities to allow for
only a subset of information to be retrieved. The query operation
MAY be a synchronous request or asynchronous request.
IM-017 Data model scalability: Use Cases 2.1.4 and 2.1.5 describes
the need for the data model to support scalability. For example,
the query operation may result in a very large set of attributes as
well as a large set of targets.
IM-018 Attribute Dictionary: Use Cases in the whole of Section 2
describe the need for an Attribute Dictionary. With SACM's scope
focused on Posture Assessment, the data model attribute collection
and aggregation MUST have a well understood set of attributes
inclusive of their meaning or usage intent.
IM-019 Transport Agnostic: the data model SHOULD be transport
agnostic, to allow for the data operations to leverage the most
appropriate transport Internet layer (e.g. Link Layer, TCP, UDP,
etc.).
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IM-020 The data model SHOULD allow the provider to include the
information's origination time.
IM-021 The data model SHOULD allow the provider to include attributs
defining how the data was generated (e.g. self-reported, reported by
aggregator, scan result, etc.).
IM-022 The data model SHOULD allow the provider to include
attributes defining the location of the data source.
IM-023 The data model SHOULD allow the provider to include
attributes defining whether the information provided is a delta,
partial or full set of information.
2.4. Requirements for Transport Protocols
The requirements for transport protocols include:
T-001 Transport variability: Different transports must be supported
to address different deployment and time constraints. Supporting
transports MAY be at the data link layer, network transport layer or
the application layers.
T-002 Data Integrity: Transport protocols MUST be able to support
data integrity.
T-003 Data Confidentiality: Transport protocols MUST be able to
support data confidentiality. Transport protocols SHOULD ensure
data protection for data in transit by encryption to provide
confidentiality, integrity and robustness against protocol-based
attacks. Note that while the transport MUST be able to support data
confidentiality, implementations MAY choose to make confidentiality
optional. Protection for data at rest is not in scope for SACM.
Data protection MAY be used for both privacy and non-privacy
scenarios.
T-004 Transport protection: Transport protocols MUST be capable of
supporting mutual authentication and replay protection.
T-005 Transport reliability: Transport protocols MUST provide
reliable delivery of data. This includes the ability to perform
fragmentation and reassembly, and detect replays.
3. Acknowledgements
The authors would like to thank Barbara Fraser, Jim Bieda and Adam
Montville for reviewing and contributing to this draft.
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4. IANA Considerations
This memo includes no request to IANA.
5. Security Considerations
This document defines the requirements for SACM. As such, it is
expected that several data models, protocols and transports may be
defined or reused from already existing standards. This section will
highlight security considerations that may apply to SACM based on the
architecture and standards applied in SACM. In particular,
highlights to security considerations that may apply to the SACM
reference architecture and standard data models and transports will
be discussed
To address security and privacy considerations, the data model,
protocols and transport must consider authorization based on consumer
function and privileges, to only allow authorized consumers and
providers to access specific information being requested or
published.
To enable federation across multiple entities (such as across
organizational or geographic boundaries) authorization must also
extend to infrastructure elements themselves, such as central
controllers / brokers / data repositories.
In addition, authorization needs to extend to specific information or
resources available in the environment. In other words,
authorization should be based on both subject (the information
requestor) and object (the information requested). The method by
which this authorization is applied is unspecified.
With SACM's charter focus on the sharing of posture information for
improving efficacy of security applications such as compliance,
configuration, assurance and other threat and vulnerability reporting
and remediation systems. While the goal is to facilitate the flow of
information securely, it is important to note that participating
endpoints may not be cooperative or trustworthy.
5.1. Trust between Provider and Requestor
The information given from the provider to a requestor may come with
different levels of trustworthiness given the different potential
deployment scenarios and compromise either at the provider, the
requestor or devices that are involved in the transport between the
provider and requestor. This section will describe the different
considerations that may reduce the level of trustworthiness of the
information provided.
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In the information transport flow, it is possible that some of the
devices may serve as proxies or brokers and as such, may be able to
observe the communications flowing between an information provider
and requester. Without appropriate protections
It is common to, in general, distrust the network service provider,
unless the full hop by hop communications process flow is well
understood. As such, the posture information provider should protect
the posture information data it provides as well as the transport it
uses. Similarly, while there may be providers whose goal is to
openly share its information, there may also be providers whose
policy is to grant access to certain posture information based on its
business or regulatory policy. In those situations, a provider may
require full authentication and authorization of the requestor (or
set of requestors) and share only the authorized information to the
authenticated and authorized requestors.
A requestor beyond distrusting the network service provider, must
also account that the information recieved from the provider may have
been communicated through an undetermined network communications
system. That is, the posture information may have traversed through
many devices before reaching the requestor. As such, providing non-
repudiation in SACM is out of scope. However, SACM specifications
should provide the means for allowing non-repudiation possible and at
minimum, provide endpoint authentication and transport integrity.
A requestor may require data freshness indications, both knowledge of
data origination as well as time of publication so that it can make
more informed decisions about the relevance of the data based on its
currency and/or age.
It is also important to note that endpoint assessment reports,
especially as they may be provided by the target endpoint may pose
untrustworthy information. The considerations for this is described
in Section 8 of [RFC5209].
The trustworthiness of the posture information given by the provider
to one or many requestors is dependent on several considerations.
Some of these include the requestor requiring:
o Full disclosure of the network topology path to the provider(s).
o Direct (peer to peer) communication with the provider.
o Authentication and authorization of the provider.
o Either or both confidentiality and integrity at the transport
layer.
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o Either or both confidentiality and integrity at the data layer.
6. References
6.1. Normative References
[I-D.ietf-sacm-terminology]
Waltermire, D., Montville, A., Harrington, D., and N. Cam-
Winget, "Terminology for Security Assessment", draft-ietf-
sacm-terminology-05 (work in progress), August 2014.
[I-D.ietf-sacm-use-cases]
Waltermire, D. and D. Harrington, "Endpoint Security
Posture Assessment - Enterprise Use Cases", draft-ietf-
sacm-use-cases-07 (work in progress), April 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J.
Tardo, "Network Endpoint Assessment (NEA): Overview and
Requirements", RFC 5209, June 2008.
6.2. Informative References
[RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between
Information Models and Data Models", RFC 3444, January
2003.
Authors' Addresses
Nancy Cam-Winget
Cisco Systems
3550 Cisco Way
San Jose, CA 95134
US
Email: ncamwing@cisco.com
Lisa Lorenzin
Pulse Secure
2700 Zanker Rd., Suite 200
San Jose, CA 95134
US
Email: llorenzin@pulsesecure.net
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