SACM Working Group S. Banghart
Internet-Draft D. Waltermire
Intended status: InformationalNational Institute of Standards and Techno
Expires: September 27, 2019 March 26, 2019
Definition of the ROLIE Software Descriptor Extension
draft-ietf-sacm-rolie-softwaredescriptor-05
Abstract
This document uses the "information-type" extension point as defined
in the Resource-Oriented Lightweight Information Exchange (ROLIE)
[RFC8322] Section 7.1.2 to better support Software Record and
Software Inventory use cases. This specification registers a new
ROLIE information-type, "software-descriptor", that allows for the
categorization of information relevant to software description
activities and formats. In particular, the usage of the ISO
19770-2:2015 (SWID Tag) and the Concise SWID (COSWID) formats in
ROLIE are standardized. Additionally, this document discusses
requirements and usage of other ROLIE elements in order to best
syndicate software description information.
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 September 27, 2019.
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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. The "software-descriptor" information type . . . . . . . . . 4
5. rolie:property Extensions . . . . . . . . . . . . . . . . . . 5
5.1. urn:ietf:params:rolie:property:swd:swname . . . . . . . . 5
5.2. urn:ietf:params:rolie:property:swd:swversion . . . . . . 6
5.3. urn:ietf:params:rolie:property:swd:swcreator . . . . . . 6
6. Data format requirements . . . . . . . . . . . . . . . . . . 6
6.1. The ISO SWID 2015 format . . . . . . . . . . . . . . . . 6
6.1.1. Description . . . . . . . . . . . . . . . . . . . . . 6
6.1.2. Requirements . . . . . . . . . . . . . . . . . . . . 7
6.2. The Concise SWID format . . . . . . . . . . . . . . . . . 7
6.2.1. Description . . . . . . . . . . . . . . . . . . . . . 8
6.2.2. Requirements . . . . . . . . . . . . . . . . . . . . 8
7. atom:link Extensions . . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8.1. software-descriptor information-type . . . . . . . . . . 11
8.2. swd:swname property . . . . . . . . . . . . . . . . . . . 11
8.3. swd:swversion property . . . . . . . . . . . . . . . . . 11
8.4. swd:swcreator property . . . . . . . . . . . . . . . . . 12
9. Security Considerations . . . . . . . . . . . . . . . . . . . 12
10. Normative References . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Schema . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix B. Examples of Use . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
This document defines an extension to the Resource-Oriented
Lightweight Information Exchange (ROLIE) [RFC8322] to support the
publication of software descriptor information. Software descriptor
information is information that characterizes static software
components, packages, and installers; including identifying,
versioning, software creation and publication, and file artifact
information.
Software descriptor information provides data about what might be
installed, but doesn't describe a specific software installation's
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configuration or execution. This static approach to software
description is a smaller state space that covers the majority of
current use cases for software inventory and record keeping.
Some possible use cases for software descriptor information ROLIE
Feeds include:
o Software providers can publish software descriptor information so
that software researchers, enterprises, and users of software can
understand the collection of software produced by that software
provider.
o Organizations can aggregate and syndicate collections of software
descriptor information provided by multiple software providers to
support software-related analysis processes (e.g., vulnerability
analysis) and value added information (e.g., software
configuration checklist repositories) using identification and
characterization information derived from software descriptor
information.
o End user organizations can consume sources of software descriptor
information, and other related software vulnerability and
configuration information to provide the data needed to automate
software asset, patch, and configuration management practices.
o Organizations can use software descriptors to support verification
of other entities, thru mechanisms such as RIM or other integrity
measurements.
This document supports these use cases by describing the content
requirements for Feeds and Entries of software descriptor information
that are to be published to or retrieved from a ROLIE repository.
2. Terminology
The key words "MUST," "MUST NOT," "REQUIRED," "SHALL," "SHALL NOT,"
"SHOULD," "SHOULD NOT," "RECOMMENDED," "MAY," and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
Several places in this document refer to the "information-type" of a
Resource (Entry or Feed). This refers to the "value" attribute of an
"atom:category" element whose scheme is
"urn:ietf:params:rolie:category:information-type". For an Entry,
this value can be inherited from it's containing Feed as per
[RFC8322].
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3. Background
In order to effectively protect and secure an endpoint, it is vital
to know what the software load of that endpoint is. This software
load, the combination of software, patches and installers on a
device, represents the majority of the endpoint's attack surface.
Unfortunately, without a reliable and secure package manager, or
otherwise a secured and managed operating system, tracking what
software is installed on an endpoint is currently not feasible
without undue effort. Even attempting to whitelist software is
difficult without a way of identifying software and its editions,
versions and hotfixes.
Software descriptor information, such as that standardized in the ISO
19770-2:2015 SWID Tag format, or expressed in proprietary enterprise
databases, attempts to provide as much data about this software as
possible.
Once this information is expressed, it needs to be stored and shared
to internal and external parties. ROLIE provides a mechanism to
handle this sharing in an automation-friendly way.
4. The "software-descriptor" information type
When an "atom:category" element has a "scheme" attribute equal to
"urn:ietf:params:rolie:category:information-type", the "value"
attribute defines the information type of the associated resource. A
new information type value: "software-descriptor", is described in
this section, and registered in Section 8.1.
The "software-descriptor" information type represents any static
information that describes a piece of software. This document uses
the definition of software provided by [RFC4949]. Note that as per
this definition, this information type pertains to static software,
that is, code on the disc. The "software-descriptor" information
type is intended to provide a category for information that does one
or more of the following:
identifies and characterizes software: This software identification
and characterization information can be provided by a large
variety of data, but always describes software in a pre-installed
state.
provides software installer metadata: This represents information
about software used to install other software. This metadata
identifies, and characterizes a software installation package or
media.
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describes stateless installation metadata: Information that
describes the software post-deployment, such as files that may be
deployed during an installation. It is expected that this
metadata is produced generally for a given installation, and may
not exactly match the actual installed files on a given endpoint.
Provided below is a non-exhaustive list of information that may be
considered to be of a software-descriptor information type.
o Naming information: IDs and names that aid in the identification
of a piece of software
o Version and patching information: Version numbers, patch
identifiers, or other information that
o Vendor and source information: Includes where the software was
developed or distributed from, as well as where the software
installation media may be located.
o Payload and file information: information that describes or
enumerates the files and folders that make up the piece of
software, and information about those files.
o Descriptive information and data: Any information that otherwise
characterizes a piece of software, such as libraries, runtime
environments, target OSes, intended purpose or audience, etc.
Note again that this list is not exhaustive, any information that in
is the abstract realm of an incident should be classified under this
information-type.
It is important to note that software descriptor information is
static for a given piece of software. That is, the information
expressed is the data that doesn't change from the publication of the
software to its final install. Information about the current status
(e.g. install location, memory usage, CPU usage, launch parameters,
job progress, etc.), is out of scope of this information type.
5. rolie:property Extensions
This document registers new valid rolie:property names as follows:
5.1. urn:ietf:params:rolie:property:swd:swname
This property provides an exposure point for the plain text name of
the software being described. Naming of software is not a well
standardized process, and software names can change between product
versions or editions. As such, care should be taken that this value
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is set as consistently as possible by generating it directly from an
attached software descriptor resource.
5.2. urn:ietf:params:rolie:property:swd:swversion
This property provides an exposure point for the version of the
software being described. This value should be generated or taken
from the software descriptor linked to by the entry. This helps
avoid, but does not prevent, inconsistent versioning schemes being
shared.
5.3. urn:ietf:params:rolie:property:swd:swcreator
This property provides an exposure point for a plain text name of the
creator of the software being described. This is in many cases an
organization or company, but certainly could be a single person.
Most software descriptor formats include this information, and where
possible, this property should be set equal to that value.
6. Data format requirements
This section defines usage guidance and additional requirements
related to data formats above and beyond those specified in
[RFC8322]. The following formats are expected to be commonly used to
express software descriptor information. For this reason, this
document specifies additional requirements to ensure
interoperability.
6.1. The ISO SWID 2015 format
6.1.1. Description
ISO/IEC 19770-2:2015 defines a software record data format referred
to as a "SWID Tag". It provides several tag types:
o primary: provides descriptive and naming information about
software,
o patch: describes non-standalone software meant to patch existing
software,
o corpus:describes the software installation media that installs a
given piece of software,
o supplemental: provides additional metadata to be deployed
alongside a tag.
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For a more complete overview as well as normative requirements, refer
to ISO/IEC 19770-2:2015 [SWID].
For additional requirements and guidance around creation of SWID
Tags, consult NIST Internal Report 8060 [NISTIR8060].
6.1.2. Requirements
For an Entry to be considered as a "SWID Tag Entry", it MUST fulfill
the following conditions:
o The information-type of the Entry is "software-descriptor". For a
typical Entry, this is derived from the information type of the
Feed it is contained in. For a standalone Entry, this is provided
by an "atom:category" element.
o The document linked to by the "href" attribute of the
"atom:content" element is a 2015 SWID Tag as per ISO/IEC
19770-2:2015.
A "SWID Tag Entry" MUST conform to the following requirements:
o The value of the "type" attribute of the "atom:content" element
MUST be "application/xml".
o There MUST be one "rolie:property" with the "name" attribute equal
to "urn:ietf:params:rolie:property:content-id" and the "value"
attribute exactly equal to the "<tagid>" element in the attached
SWID Tag. This allows for ROLIE consumers to more easily search
for SWID tags without needing to download the tag itself.
o There MUST be one "rolie:property" with the "name" attribute equal
to "urn:ietf:params:rolie:property:swd:swname", and the "value"
attribute equal to the value of the "<name>" element in the
attached SWID Tag. As above, this field aids ROLIE consumers in
search and filtering Entries.
o There MAY be a property element with the "name" attribute equal to
"urn:ietf:params:rolie:property:swd:swversion". When this
property appears, it's value MUST be equal to the value of the
"TODO-version" element in the attached SWID Tag.
6.2. The Concise SWID format
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6.2.1. Description
The Concise SWID (COSWID) format is an alternative representation of
the SWID Tag format using a Concise Binary Object Representation
(CBOR) encoding. This provides the format with a reduced size that
is more suitable for constrained devices. It provides the same
features and attributes as are specified in ISO 19770-2:2015, plus:
o a straight forward method to sign and encrypt using COSE, and
o additional attributes that provide an improved structure to
include file hashes intended to be used as Reference Integrity
Measurements (RIM).
For more information and the complete specification, refer to the
COSWID internet draft [I-D.ietf-sacm-coswid].
6.2.2. Requirements
For an Entry to be considered as a "COSWID Tag Entry", it MUST
fulfill the following conditions:
o The information-type of the Entry is "software-descriptor". For a
typical Entry, this is derived from the information-type of the
Feed it is contained in. For a standalone Entry, this is provided
by an "atom:category" element.
o The document linked to by the "href" attribute of the
"atom:content" element is a COSWID Tag as per
[I-D.ietf-sacm-coswid]
A "COSWID Tag Entry" MUST conform to the following requirements:
o The value of the "type" attribute of the atom:content element MUST
be "application/coswid+cbor".
o There MUST be one "rolie:property" with the "name" attribute equal
to "urn:ietf:params:rolie:property:content-id" and the "value"
attribute exactly equal to the "tag-id" element in the attached
COSWID Tag. This allows for ROLIE consumers to more easily search
for COSWID tags without needing to download the tag itself.
o There MUST be one "rolie:property" with the "name" attribute equal
to "urn:ietf:params:rolie:property:swd:swname", and the "value"
attribute equal to the value of the "swid-name" element in the
attached COSWID Tag. As above, this field aids ROLIE consumers in
searching and filtering Entries.
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o There MAY be a property element with the "name" attribute equal to
"urn:ietf:params:rolie:property:swd:swversion". When this
property appears, it's value MUST be equal to the value of the
"TODO-version" element in the attached COSWID Tag.
7. atom:link Extensions
This section defines additional link relationships that
implementations MUST support. These relationships are not registered
in the Link Relation IANA table as their use case is too narrow.
Each relationship is named and described.
These relations come in related pairs. The first of each pair is
expected to be more common, as they can be determined at the time
that the Entry is created. The second of each pair will often need
to be added retroactively to an Entry.
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+----------------------+--------------------------------------------+
| Name | Description |
+----------------------+--------------------------------------------+
| ancestor | Links to a software descriptor resource |
| | that defines an ancestor of the software |
| | being described by this Entry. This is |
| | usually a previous version of the |
| | software. |
| descendent | Links to a software descriptor resource |
| | that defines an descendent of the software |
| | being described by this Entry. This is |
| | usually a more recent version or edition |
| | of the software. |
| patches | Links to a software descriptor resource |
| | that defines the software being patched by |
| | this software |
| patchedby | Links to a software descriptor resource |
| | that defines the patch or update itself |
| | that can be or has been applied to this |
| | software. |
| requires | Links to a software descriptor resource |
| | that defines a piece of software required |
| | for this software to function properly, |
| | i.e., a dependency. |
| requiredBy | Links to a software descriptor resource |
| | that defines a piece of software that |
| | requires this software to function |
| | properly. |
| installs | Links to a software descriptor resource |
| | that defines the software that is |
| | installed by this software. |
| installedBy | Links to a software descriptor resource |
| | that defines the software package that |
| | installs this software. |
| patchesVulnerability | Links to a vulnerability that this |
| | software update fixes. Used for software |
| | descriptors that are describing software |
| | patches or updates. |
| hasVulnerability | Links to a vulnerability description |
| | object that details a vulnerability that |
| | this software has. |
+----------------------+--------------------------------------------+
Table 1: Link Relations for Resource-Oriented Lightweight Indicator
Exchange
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8. IANA Considerations
8.1. software-descriptor information-type
IANA has added an entry to the "ROLIE Security Resource Information
Type Sub-Registry" registry located at
<https://www.iana.org/assignments/rolie/category/information-type> .
The entry is as follows:
name: software-descriptor
index: TBD
reference: This document, Section 4
8.2. swd:swname property
IANA has added an entry to the "ROLIE URN Parameters" registry
located in <https://www.iana.org/assignments/rolie/>.
The entry is as follows:
name: property:swd:swname
Extension IRI: urn:ietf:params:rolie:property:swd:swname
Reference: This document, Section 5.1
Subregistry: None
8.3. swd:swversion property
IANA has added an entry to the "ROLIE URN Parameters" registry
located in <https://www.iana.org/assignments/rolie/>.
The entry is as follows:
name: property:swd:swversion
Extension IRI: urn:ietf:params:rolie:property:swd:swversion
Reference: This document, Section 5.1
Subregistry: None
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8.4. swd:swcreator property
IANA has added an entry to the "ROLIE URN Parameters" registry
located in <https://www.iana.org/assignments/rolie/>.
The entry is as follows:
name: property:swd:swcreator
Extension IRI: urn:ietf:params:rolie:property:swd:swcreator
Reference: This document, Section 5.1
Subregistry: None
9. Security Considerations
Use of this extension implies dealing with the security implications
of both ROLIE and of software descriptors in general. As with any
data, care should be taken to verify the trustworthiness and veracity
of the descriptor information to the fullest extent possible.
Ideally, software descriptors should have been signed by the software
manufacturer, or signed by whichever agent processed the source code.
Software descriptor documents from these sources are more likely to
be accurate than those generated by scraping installed software.
These "authoritative" sources of software descriptor content should
consider additional security for their ROLIE repository beyond the
typical recommendations, as the central importance of the repository
is likely to make it a target.
Version information is often represented differently across
manufacturers and even across product releases. If using software
version information for low fault tolerance comparisons and searches,
care should be taken that the correct version scheme is being
utilized.
10. Normative References
[I-D.ietf-sacm-coswid]
Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D.
Waltermire, "Concise Software Identifiers", draft-ietf-
sacm-coswid-08 (work in progress), November 2018.
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[NISTIR8060]
Waltermire, D., Cheikes, B., Feldman, L., and G. Witte,
"Guidelines for the Creation of Interoperable Software
Identification (SWID) Tags", NISTIR 8060, April 2016,
<https://doi.org/10.6028/NIST.IR.8060>.
[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>.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>.
[RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident
Object Description Exchange Format", RFC 5070,
DOI 10.17487/RFC5070, December 2007,
<https://www.rfc-editor.org/info/rfc5070>.
[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>.
[SWID] "Information technology - Software asset management - Part
2: Software identification tag", ISO/IEC 19770-2:2015,
October 2015.
Appendix A. Schema
This document does not require any schema extensions.
Appendix B. Examples of Use
Use of this extension in a ROLIE repository will not typically change
that repository's operation. As such, the general examples provided
by the ROLIE core document would serve as examples. Provided below
is a sample software descriptor ROLIE entry:
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<?xml version="1.0" encoding="UTF-8"?>
<entry xmlns="http://www.w3.org/2005/Atom"
xmlns:rolie="urn:ietf:params:xml:ns:rolie-1.0">
<id>dd786dba-88e6-440b-9158-b8fae67ef67c</id>
<title>Sample Software Descriptor</title>
<published>2015-08-04T18:13:51.0Z</published>
<updated>2015-08-05T18:13:51.0Z</updated>
<summary>A descriptor for a piece of software published by this
organization. </summary>
<link rel="self" href="http://www.example.org/rolie/SWD/123456"/>
<link rel="feed" href="http://www.example.org/rolie/SWD/"/>
<link rel="requires" href="http://www.example.org/rolie/SWD/78430"/>
<rolie:property name=urn:ietf:params:rolie:property:swd:swname
value="Example Software Name"/>
<category
scheme="urn:ietf:params:rolie:category:information-type"
term="software-descriptor"/>
<rolie:format
ns="http://standards.iso.org/iso/19770/-2/2015/schema.xsd"/>
<content type="application/swid+xml"
src="http://www.example.org/rolie/SWD/123456/data"/>
</entry>
Authors' Addresses
Stephen Banghart
National Institute of Standards and Technology
100 Bureau Drive
Gaithersburg, Maryland 20877
USA
Email: stephen.banghart@nist.gov
David Waltermire
National Institute of Standards and Technology
100 Bureau Drive
Gaithersburg, Maryland 20877
USA
Email: david.waltermire@nist.gov
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