Internet DRAFT - draft-ietf-mile-rolie-vuln
draft-ietf-mile-rolie-vuln
MILE Working Group S. Banghart
Internet-Draft NIST
Intended status: Standards Track October 28, 2019
Expires: April 30, 2020
Definition of the ROLIE Vulnerability Extension
draft-ietf-mile-rolie-vuln-03
Abstract
This document extends the Resource-Oriented Lightweight Information
Exchange (ROLIE) core to add the information type categories and
related requirements needed to support Vulnerability use cases.
Additional categories, properties, and requirements based on content
type enables a higher level of interoperability between ROLIE
implementations, and richer metadata for ROLIE consumers. In
particular, usage of the Common Vulnerability Enumeration (CVE) [cve]
format is discussed.
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
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This Internet-Draft will expire on April 30, 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
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include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The "vulnerability" information type . . . . . . . . . . . . 3
4. Common Vulnerability Enumeration (CVE) Format . . . . . . . . 4
4.1. Description . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 5
5. Link relations for the 'vulnerability'
information-type . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6.1. information-type registrations . . . . . . . . . . . . . 6
6.1.1. vulnerability information-type . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
As our software becomes more complex and interconnected, the number
of software vulnerabilities exploitable by actors with mal-intent has
skyrocketed. Huge amounts of resources have been poured into the
preemptive discovery, description, and remediation of these
vulnerabilities, but it is often a challenge to share and communicate
the results of these efforts. While bad-actors have vast
collaboration networks that enable widespread knowledge of any
vulnerability, the defensive community at large has no sharing
consortium as prevalent. If we are to keep up with the rising
difficulty of defending our systems, we must increase our ability to
quickly, efficiently, and automatically share information about
vulnerabilities.
The Resource-Oriented Lightweight Information Exchange (ROLIE)
[RFC8322] provides a means to share computer security information
with an eye towards automation and efficiency. By utilizing ROLIE to
share vulnerability data, we get one step closer to establishing
automated communication between each party involved in fighting
vulnerabilities. A security researcher can send a newly discovered
vulnerability to a vulnerability repository, where it is
automatically retrieved and consumed by enterprise systems. At this
final stage, the enterprise can cross-reference against their
enterprise wide software load to begin mitigating the issue.
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This extension to ROLIE introduces new requirements and IANA
registrations to allow ROLIE repositories to share vulnerability data
in a standardized and compatible way.
This extension does not attempt to solve the vulnerability data
format issue, as this work is being done across standards groups and
industry consortiums. Instead, this extension serves to address the
problem of sharing these data formats to downstream consumers in a
automated and efficient fashion.
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 [RFC8174].
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 there.
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].
This document uses the definition of "vulnerability" given by
[RFC4949].
3. The "vulnerability" 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 attribute: "vulnerability", is described in
this section, and registered in Section 6.1.1. When this value is
used, the resource in question is considered to have an information-
type of "vulnerability" as per [RFC8322] Section 7.1.2.
The "vulnerability" information-type represents any information
describing or pertaining to a computer security vulnerability. This
document uses the definition of vulnerability provided by [RFC4949].
Provided below is a non-exhaustive list of information that may be
considered to be of a vulnerability information type.
o Fundamental identifying information, such as a global ID or
number, that identifies a given vulnerability.
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o Descriptive information, including but not limited to:
* Severity scoring - using some standardized scoring algorithm or
otherwise,
* Execution details - how the vulnerability is exploited
* Impact - what the consequences are of this vulnerability
* History and provenance data - when was the vulnerability
discovered, when was it reported and to whom,
* Plain text description of any of the above
o Metadata attached to a vulnerability, such as information about
the entity that discovered or described the vulnerability.
Note again that this list is not exhaustive: any information that is
in the abstract realm of a vulnerability should be classified under
this information-type. The final decision as to the information type
of an Entry is up to the provider and author of the Entry.
4. Common Vulnerability Enumeration (CVE) Format
4.1. Description
The Common Vulnerability Enumeration (CVE) provides a globally unique
identifier for vulnerabilities. Each CVE provides a CVE-ID, by which
a vulnerability can be referred to in any context, as well as
descriptive information about that vulnerability.
For more information and in-depth specifications, please see [cve].
CVE provides a valuable set of information fields, but itself does
not provide a standardized data format. This extension provides
standardization around two common serializations of the CVE standard,
both used by the National Institute of Standards and Technology
(NIST) National Vulnerability Database (NVD). The NVD provides a
repository of "CVE Entries" available in either serialization format.
The first format is XML-based: the NIST NVD CVE Entry format
[nvdcvexml], and the second is JSON-based: NIST NVD JSON CVE Entry
Format [nvdcvejson]. These two representations of a CVE are
equivalent, and can be losslessly converted.
This section defines usage guidance and additional requirements above
and beyond those specified in [RFC8322] that apply when CVE data
formats are in use.
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4.2. Requirements
For an Entry to be considered a "CVE Entry", it MUST fulfill the
following conditions:
o The information-type of the Entry is "vulnerability". 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 "ref" attribute of the
"atom:content" element is a CVE Entry as defined by either
[nvdcvexml] or [nvdcvejson]. Other well-defined CVE
serializations would be valid but would not be subject to the
following requirements, reducing their interoperability.
The XML and JSON NVD formats follow different requirements.
A "XML CVE 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 "<name>" element in the attached
CVE Entry. This allows for ROLIE consumers to more easily search
for CVE Entries without needing to download the entry itself.
A "JSON CVE Entry" MUST conform to the following requirements:
o The value of the "type" attribute of the "atom:content" element
MUST be "application/json".
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 "cve:{cve_data_meta":{ID}}" element
in the attached CVE Entry. This allows for ROLIE consumers to
more easily search for CVE Entries without needing to download the
entry itself.
5. Link relations for the 'vulnerability' information-type
The atom:link element contains a "rel" attribute that describes the
semantic meaning of the given link.
If the category of an Entry is the vulnerability information type,
then the following link relations MUST be respected, that is, not
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removed, by the server. Implementations can provide extra
functionality by understanding the semantic meaning of these
relations.
+----------+--------------------------------------------------------+
| Name | Description |
+----------+--------------------------------------------------------+
| severity | Links to a document describing or scoring the severity |
| | of this vulnerability. |
+----------+--------------------------------------------------------+
Table 1: Link Relations for Resource-Oriented Lightweight Indicator
Exchange
6. IANA Considerations
6.1. information-type registrations
IANA has added the following entries to the "ROLIE Security Resource
Information Type Sub-Registry" registry located at
<https://www.iana.org/assignments/rolie/category/information-type> .
6.1.1. vulnerability information-type
The entry is as follows:
name: vulnerability
index: TBD
reference: This document, Section 3
7. Security Considerations
All security considerations of the core ROLIE document apply to use
of this extension.
The use of this particular extension implies the use of ROLIE in
sharing vulnerability information. In automated use cases,
downstream consumers may be dynamically acquiring and acting on
vulnerabilities posted to a ROLIE repository. In this case, a
compromised server could serve up false vulnerability information to
trigger dangerous activity in automated consumers. Automatic
remediation solutions that consume shared vulnerability information
in high risk use cases should take care to verify data before taking
action. If some global ID, such as a CVE-ID, is included, this
verification should be trivial.
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8. Normative References
[cve] "Common Vulnerability Enumeration",
<https://cve.mitre.org/about/index.html>.
[cvexml] The MITRE Corporation, ,
<https://cve.mitre.org/schema/cve/cve_1.0.xsd>.
[nvdcvejson]
National Institute of Standards and Technology, "NVD CVE
Entry JSON Schema",
<https://csrc.nist.gov/schema/nvd/feed/1.0/
nvd_cve_feed_json_1.0.schema>.
[nvdcvexml]
National Institute of Standards and Technology, "NVD CVE
Entry XML Schema",
<https://csrc.nist.gov/schema/nvd/nvdcve.xsdf>.
[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>.
[RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom
Syndication Format", RFC 4287, DOI 10.17487/RFC4287,
December 2005, <https://www.rfc-editor.org/info/rfc4287>.
[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>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
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Author's Address
Stephen A. Banghart
National Institute of Standards and Technology
100 Bureau Drive
Gaithersburg, Maryland
USA
Phone: (301)975-4288
Email: stephen.banghart@nist.gov
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