MILE Working Group S. Banghart
Internet-Draft NIST
Intended status: Informational March 28, 2019
Expires: September 29, 2019
Definition of the ROLIE Vulnerability Extension
draft-ietf-mile-rolie-vuln-00
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 and the draft Vulnerability Description Ontology (VDO) [vdo]
are 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
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 September 29, 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
Banghart Expires September 29, 2019 [Page 1]
Internet-Draft ROLIE Vuln March 2019
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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. The "vulnerability" information type . . . . . . . . . . . . 3
4. Data Format Requirements . . . . . . . . . . . . . . . . . . 3
4.1. CVE Format . . . . . . . . . . . . . . . . . . . . . . . 4
4.1.1. Description . . . . . . . . . . . . . . . . . . . . . 4
4.1.2. Requirements . . . . . . . . . . . . . . . . . . . . 4
4.2. VDO Format . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.1. Description . . . . . . . . . . . . . . . . . . . . . 5
4.2.2. Usage . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Use of the atom:link element . . . . . . . . . . . . . . . . 5
5.1. Link relations for the 'vulnerability'
information-type . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6.1. information-type registrations . . . . . . . . . . . . . 6
6.1.1. vulnerability information-type . . . . . . . . . . . 6
6.2. rolie:property name registrations . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Vulnerability data is used in a wide variety of security use cases.
Researchers, CSIRTs, enterprises, software vendors, and consumers all
have a need to communicate about computer vulnerabilities. Today, a
number of formats are used to describe these vulnerabilities, some of
them are standardized, some of them are proprietary, and some of them
are as rudimentary as a vaguely descriptive email message.
This extension does not attempt to solve the vulnerability data
format issue, 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 [RFC2119].
Banghart Expires September 29, 2019 [Page 2]
Internet-Draft ROLIE Vuln March 2019
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.
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 in
is the abstract realm of an vulnerability should be classified under
this information-type.
4. 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.
Banghart Expires September 29, 2019 [Page 3]
Internet-Draft ROLIE Vuln March 2019
4.1. CVE Format
4.1.1. 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 is
standardized around the NIST NVD CVE Entry format [nvdcvexml]. There
is a second format using the CVE information fields, defined in JSON
Schema 1.0 [nvdcvejson]. These two representations of a CVE are
equivalent, so either are valid when used in a ROLIE CVE Entry.
4.1.2. Requirements
For an Entry to be considered as 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].
The XML and JSON formats follow different requirements. From here on
out we will refer to "CVE Entry" which is defined above, and is in
the XML or JSON formats, "XML CVE Entry", which is defined in the XML
format, and "JSON CVE Entry", which is defined in the JSON format.
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.
Banghart Expires September 29, 2019 [Page 4]
Internet-Draft ROLIE Vuln March 2019
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.
4.2. VDO Format
4.2.1. Description
The Vulnerability Description Ontology (VDO) provides a dictionary
and ontology for standardizing human language descriptions of
vulnerabilities. CVEs expose a decent amount of information, but one
of those fields is a plain text description. The VDO provides a
means of completing this description in a way that makes it machine
parsable and universally understandable across organizations.
The VDO is currently defined in a draft National Institute of
Standards and Technology (NIST) internal report. As this draft is
not yet fully stable, this document will provide only guidance on
using the VDO inside a ROLIE repository.
For more in depth information please find the draft at [vdo]
4.2.2. Usage
There is currently no standardized data format for the VDO, as such,
there can be no ROLIE "VDO Entry". Instead, the VDO can be utilized
in plain text fields in an Entry. ROLIE properties can contain long
strings of text, exposing human language information. In the
vulnerability context, these human language fields can be filled in
using the VDO.
It is not recommended that the content element be populated with some
plain text format using the VDO.
5. Use of the atom:link element
These sections define requirements for atom:link elements in Entries.
Note that the requirements are determined by the information type
that appears in either the Entry or in the parent Feed.
Banghart Expires September 29, 2019 [Page 5]
Internet-Draft ROLIE Vuln March 2019
5.1. Link relations for the 'vulnerability' information-type
If the category of an Entry is the vulnerability information type,
then the following requirements MUST be followed for support of
atom:link elements.
+----------+--------------------------------------------------------+
| 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
6.2. rolie:property name registrations
IANA has added the following entries to the "ROLIE URN Parameters"
registry located in <https://www.iana.org/assignments/rolie/>.
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
Banghart Expires September 29, 2019 [Page 6]
Internet-Draft ROLIE Vuln March 2019
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.
8. Normative References
[cve] "Common Vulnerability Enumeration", <cve.mitre.org>.
[nvdcvejson]
"NVD CVE Entry JSON Schema",
<https://csrc.nist.gov/schema/nvd/feed/1.0/
nvd_cve_feed_json_1.0.schema>.
[nvdcvexml]
"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>.
[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>.
[vdo] "Vulnerability Description Ontology", <https://csrc.nist.g
ov/CSRC/media/Publications/nistir/8138/draft/documents/
nistir_8138_draft.pdf>.
Banghart Expires September 29, 2019 [Page 7]
Internet-Draft ROLIE Vuln March 2019
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
Banghart Expires September 29, 2019 [Page 8]