Internet DRAFT - draft-ietf-sacm-rolie-softwaredescriptor
draft-ietf-sacm-rolie-softwaredescriptor
SACM Working Group S. Banghart
Internet-Draft D. Waltermire
Intended status: Informational NIST
Expires: January 22, 2020 July 21, 2019
Definition of the ROLIE Software Descriptor Extension
draft-ietf-sacm-rolie-softwaredescriptor-08
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 Software Identification Tag (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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 22, 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
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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 . . . . . . . . . . . . . . . . . . . . . 7
6.2.2. Requirements . . . . . . . . . . . . . . . . . . . . 8
7. atom:link Extensions . . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8.1. software-descriptor information-type . . . . . . . . . . 10
8.2. swd:swname property . . . . . . . . . . . . . . . . . . . 10
8.3. swd:swversion property . . . . . . . . . . . . . . . . . 11
8.4. swd:swcreator property . . . . . . . . . . . . . . . . . 11
9. Security Considerations . . . . . . . . . . . . . . . . . . . 11
10. Normative References . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Schema . . . . . . . . . . . . . . . . . . . . . . . 12
Appendix B. Examples of Use . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
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 identification,
version, 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 tightly limited scope that still covers the majority
of current use cases for software inventory and record keeping.
Some possible use cases for software descriptor information ROLIE
Feeds (Section 6.1 of [RFC8322]) 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 to provide downsteam services (e.g., software
configuration checklist repositories).
o End user organizations can consume software descriptor information
along with 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 through integrity measurement mechanisms.
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].
As an extension of [RFC8322], this document refers to many terms
defined in that document. In particular, the use of "Entry" and
"Feed" are aligned with the definitions presented in RFC8322.
Several places in this document refer to the "information-type" of a
Resource (Entry or Feed). This refers to the "term" 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. Software load,
the combination of software, patches and installers on a device,
represents a significant portion of the endpoint's attack surface.
Unfortunately, without a reliable and secure package manager, or a
secured and managed operating system with strict software
whitelisting, 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 Software Identification Tag (SWID) 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 "term"
attribute defines the information type of the associated resource. A
new valid value for this "term": "software-descriptor", is described
in this section and registered in Section 8.1. When this value is
used, the resource in question is considered to have an information-
type of "software-descriptor" as per [RFC8322] Section 7.1.2.
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: information that provides
quantative and qualitative data describing software. This
information identifies and charaterizes a given instance of
software.
provides software installer metadata: 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 relates to software updates
and patches.
o Vendor and source information: Includes where the software was
developed or distributed, 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 operating systems, intended purpose or
audience, etc.
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
is set as consistently as possible by generating it directly from an
attached software descriptor resource.
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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.
For a more complete overview as well as normative requirements, refer
to ISO/IEC 19770-2:2015 [SWID].
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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 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 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 helps ROLIE consumers search and
filter 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, its value MUST be equal to the value of the
"version" element in the attached SWID Tag.
6.2. The Concise SWID format
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. CBOR provides the format with a reduced size that
is more suitable for constrained devices. COSWID provides the same
features and attributes as are specified in ISO 19770-2:2015, plus:
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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 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/swid+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 decoded "tag-id" element in the
attached COSWID Tag (mapped to integer 0). This allows 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 decoded value of the "swid-name" element in
the attached COSWID Tag (mapped to the integer 1). As above, this
helps ROLIE consumers search and filter 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 decoded value of
the tag-version element in the attached COSWID Tag (mapped to the
integer 12).
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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.
+----------------------+--------------------------------------------+
| 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. |
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+----------------------+--------------------------------------------+
| patchesVulnerability | Links to a vulnerability that this |
| | software update fixes. Used for software |
| | descriptors that describe 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
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
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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
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 be 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.
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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 used.
10. Normative References
[I-D.ietf-sacm-coswid]
Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D.
Waltermire, "Concise Software Identification Tags", draft-
ietf-sacm-coswid-11 (work in progress), June 2019.
[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, <https://www.iso.org/standard/65666.html>.
Appendix A. Schema
This document does not require any schema extensions.
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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:
<?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/xml"
src="http://www.example.org/rolie/SWD/123456/data"/>
</entry>
Authors' Addresses
Stephen Banghart
NIST
100 Bureau Drive
Gaithersburg, Maryland 20877
USA
Email: stephen.banghart@nist.gov
David Waltermire
NIST
100 Bureau Drive
Gaithersburg, Maryland 20877
USA
Email: david.waltermire@nist.gov
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