Individual Submission T. Takahashi
Internet-Draft NICT
Intended status: Standards Track K. Landfield
Expires: April 7, 2012 McAfee
T. Millar
USCERT
Y. Kadobayashi
NICT
Oct 5, 2011
IODEF-extension to support structured cybersecurity information
draft-takahashi-mile-sci-01.txt
Abstract
This document extends the Incident Object Description Exchange Format
(IODEF) defined in RFC 5070 [RFC5070] to facilitate enriched
cybersecurity information exchange among cybersecurity entities by
embedding structured information formatted by specifications,
including CAPEC[TM], CEE[TM], CPE[TM], CVE(R), CVRF, CVSS, CWE[TM],
CWSS[TM], ISO/IEC 19770-2, OCIL, OVAL(R), XCCDF, and XDAS.
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 http://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 April 7, 2012.
Copyright Notice
Copyright (c) 2011 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
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Extension Definition . . . . . . . . . . . . . . . . . . . . . 4
4.1. Structured Cybersecurity Information Formats . . . . . . . 4
4.2. Extended Data Types . . . . . . . . . . . . . . . . . . . 5
4.2.1. EM_XML . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3. Extended Classes . . . . . . . . . . . . . . . . . . . . . 6
4.3.1. AttackPattern . . . . . . . . . . . . . . . . . . . . 7
4.3.2. PlatformID . . . . . . . . . . . . . . . . . . . . . . 8
4.3.3. Vulnerability . . . . . . . . . . . . . . . . . . . . 9
4.3.4. Scoring . . . . . . . . . . . . . . . . . . . . . . . 10
4.3.5. Weakness . . . . . . . . . . . . . . . . . . . . . . . 11
4.3.6. EventReport . . . . . . . . . . . . . . . . . . . . . 13
4.3.7. Remediation . . . . . . . . . . . . . . . . . . . . . 14
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Reporting an attack . . . . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6.1. Transport-Specific Concerns . . . . . . . . . . . . . . . 18
6.2. Using the iodef:restriction Attribute . . . . . . . . . . 18
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
8. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 19
9. Appendix: XML Schema Definition for Extension . . . . . . . . 19
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
10.1. Normative References . . . . . . . . . . . . . . . . . . . 22
10.2. Informative References . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
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1. Introduction
Cyber attacks are getting more sophisticated, and their numbers are
increasing day by day. To cope with such situation, incident
information needs to be reported, exchanged, and shared among
organizations. IODEF is one of the tools enabling such exchange, and
is already in use.
To efficiently run cybersecurity operations, these exchnaged
information needs to be machine-readable. IODEF provides a
structured means to describe the information, but it needs to embed
various non-structured such information in order to convery detailed
information. Further strucuture within IODEF increases IODEF
documents' machine-readability and thus facilitates streamlining
cybersecurity operations.
On the other hand, there exist various other activities facilitating
detailed and structured description of cybersecurity information,
major of which includes [CAPEC], [CEE], [CPE], [CVE], [CVRF], [CVSS],
[CWE], [CWSS], [ISO/IEC 19770-2], [OCIL], [OVAL], [XCCDF], and
[XDAS]. Since such structured description facilitates cybersecurity
operations, it would be beneficial to embed and convey these
information inside IODEF document.
To enable that, this document extends the IODEF to embed and convey
various structured cybersecurity information, with which
cybersecurity operations can be facilitated. Since IODEF defines a
flexible and extensible format and supports a granular level of
specificity, this document defines an extension to IODEF instead of
defining a new report format. For clarity, and to eliminate
duplication, only the additional structures necessary for describing
the exchange of such structured information are provided.
2. Terminology
The terminology used in this document follows the one defined in
[RFC5070].
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].
3. Applicability
To maintain cybersecurity, organization needs to exchange
cybersecurity information, which includes the following information:
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attack pattern, platform information, vulnerability and weakness,
countermeasure instruction, computer event log, and the severity.
IODEF provides a scheme to exchange such information among interested
parties. However, the detailed common format to describe such
information is not defined in the IODEF base document.
On the other hand, to describe those information and to facilitate
exchange, a structured format for that is already available. Major
of them are CAPEC, CEE, CPE, CVE, CVRF, CVSS, CWE, CWSS, OVAL, and
XCCDF. By embedding them into the IODEF document, the document can
convey more detailed contents to the receivers, and the document can
be easily reused.
These structured cybersecurity information facilitates cybersecurity
operation at the receiver side. Since the information is machine-
readable, the data can be processed by computers. That expedites the
automation of cybersecurity operations
For instance, an organization wishing to report a security incident
wants to describe what vulnerability was exploited. Then the sender
can simply use IODEF, where an CAPEC record is embedded instead of
describing everything in free format text. Receiver can also
identify the needed details of the attack pattern by looking up some
of the xml tags defined by CAPEC. Receiver can accumulate the attack
pattern information (CAPEC record) in its database and could
distribute it to the interested parties if needed, without needing
human interventions.
4. Extension Definition
This draft extends IODEF to embed structured cybersecurity
information by introducing new classes, with which these information
can be embedded inside IODEF document as element contents of
AdditionalData and RecordItem classes.
4.1. Structured Cybersecurity Information Formats
This extension intends to embed various structured cybersecurity
information. The below table describes the initial list of supported
specifications and their IDs, versions, and namespaces; future
assignments are to be made through Expert Review, as requested in
Section 7.
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ID Specification Name Version Namespace
--------- ---------------------- ------- ------------------------
CAPEC_1.6 Common Attack Pattern 1.6 http://capec.mitre.org
Enumeration and /observables
Classification (CAPEC)
CEE_0.6 Common Event Expression 0.6 http://cee.mitre.org
(CEE)
CPE_2.3 Common Platform 2.3 http://cpe.mitre.org
Enumeration (CPE) /language/2.0
CVE_1.0 Common Vulnerability 1.0 http://cve.mitre.org
and Exposures (CVE) /cve/downloads/1.0
CVRF_1.0 Common Vulnerability 1.0 http://www.icasi.org
Reporting Format /CVRF/schema/cvrf/1.0
(CVRF)
CVSS_2.0 Common Vulnerability 2 http://scap.nist.gov
Scoring System (CVSS) /schema/cvss-v2/1.0
CWE_5.0 Common Weakness 5.0 TBD
Enumeration (CWE)
CWSS_0.8 Common Weakness 0.8 TBD
Scoring System (CWSS)
OCIL_2.0 Open Checklist 2.0 http://www.mitre.org
Interactive Language /ocil/2.0
(OCIL)
OVAL_5.10 Open Vulnerability and 5.10 http://oval.mitre.org
Assessment Language /XMLSchema
(OVAL) /oval-definitions-5
XCCDF_1.2 Extensible 1.2 http://checklists.nist
Configuration .gov/xccdf/1.2
Checklist Description
Format (XCCDF)
XDAS_1998 Distributed Audit 1998 TBD
Service (XDAS)
19770-2 ISO/IEC 19770 Part 2 TBD
Figure 1: List of specifications
4.2. Extended Data Types
This extension inherits all of the data types defined in the IODEF
model. One data type is added: EM_XML.
4.2.1. EM_XML
An embedded complete XML document is represented by the EM_XML data
type. The elements of the document must match its root namespace
element.
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4.3. Extended Classes
The IODEF Incident element ([RFC5070], Section 3.2) is summarized
below. It is expressed in Unified Modeling Language (UML) syntax as
used in the IODEF specification. The UML representation is for
illustrative purposes only; elements are specified in XML as defined
in Appendix A.
+--------------------+
| Incident |
+--------------------+
| ENUM purpose |<>----------[ IncidentID ]
| STRING ext-purpose |<>--{0..1}--[ AlternativeID ]
| ENUM lang |<>--{0..1}--[ RelatedActivity ]
| ENUM restriction |<>--{0..1}--[ DetectTime ]
| |<>--{0..1}--[ StartTime ]
| |<>--{0..1}--[ EndTime ]
| |<>----------[ ReportTime ]
| |<>--{0..*}--[ Description ]
| |<>--{1..*}--[ Assessment ]
| |<>--{0..*}--[ Method ]
| | |<>--[ AdditionalData ]
| | |<>--[ AttackPattern ]
| | |<>--[ Vulnerability ]
| | |<>--[ Weakness ]
| |<>--{1..*}--[ Contact ]
| |<>--{0..*}--[ EventData ]
| | |<>--[ Flow ]
| | | |<>--[ System ]
| | | |<>--[ AdditionalData ]
| | | |<>--[ PlatformID ]
| | |<>--[ Expectation ]
| | |<>--[ Record ]
| | |<>--[ RecordData ]
| | |<>--[ RecordItem ]
| | |<>--[ EventReport ]
| |<>--{0..1}--[ History ]
| |<>--{0..*}--[ AdditionalData ]
| | |<>--[ Remediation ]
+--------------------+
Figure 2: Incident class
This extension defines the following seven elements.
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4.3.1. AttackPattern
An AttackPattern consists of an extension to the
Incident.Method.AdditionalData element with a dtype of "xml". The
extension describes attack patterns of incidents or events.
It is recommended that Method class SHOULD contain one or more of the
extension elements whenever available.
An AttackPattern class is structured as follows.
+------------------------+
| AttackPattern |
+------------------------+
| STRING Version |<>--(0..*)--[ Record ]
| ENUM SpecificationID |<>--(0..*)--[ Reference ]
| STRING AttackPatternID |<>--(0..*)--[ PlatformID ]
+------------------------+
Figure 3: AttackPattern class
This class has the following attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the Record element. The
value should be chosen from the IDs listed in Figure 1, such as
CAPEC_1.6. Note that the lists in Figure 1 will be developed
further by IANA.
AttackPatternID: OPTIONAL. STRING. An ID of attack pattern to be
reported. This attribute SHOULD be used whenever such ID is
available, but could be omitted if no such ID is available. In
case Record or Reference elements are provided, writers/senders
MUST ensure that this ID is consistent with the one provided by
the Record or Reference elements; if a reader/receiver detects an
inconsistency, it SHOULD prefer the AttackPatternID, and SHOULD
log the inconsistency so a human can correct the problem.
The AttackPattern class is composed of the following aggregate
classes.
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Record: Zero or more. EM_XML. A complete document that is
formatted according to the specification and its version
identified by the value of the SpecificationID with the Figure 1.
Reference: Zero or more of iodef:Reference [RFC5070]. This element
allows an IODEF document to include a link to a structured
information instead of directly embedding it into a Record
element.
PlatformID: Zero or more. An identifier of software platform
involved in the specific attack pattern, which is elaborated in
Section 4.3.2.
Writers/senders MUST ensure the specification name and version
identified by the SpecificationID are consistent with the contents of
the Record; if a reader/receiver detects an inconsistency, it SHOULD
prefer the specification name and version derived from the content,
and SHOULD log the inconsistency so a human can correct the problem.
4.3.2. PlatformID
A PlatformID identifies a software platform. It is recommended that
AttackPattern, Vulnerability, Weakness, and System classes contain
this elements whenever available.
A PlatformID element is structured as follows.
+----------------------+
| PlatformID |
+----------------------+
| STRING Version |<>--(1..*)--[ ID ]
| ENUM SpecificationID |
+----------------------+
Figure 4: PlatformID class
This class has the following attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the ID element. The value
should be chosen from the IDs listed in Figure 1, such as CPE_2.3
and 19770-2. Note that the lists in Figure 1 will be developed
further by IANA.
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This class is composed of the following aggregate classes.
ID: One or more. ML_STRING. An ID that is formatted according to
the rule defined by the specification and its version identified
by the value of the SpecificationID with the Figure 1.
Writers/senders MUST ensure the specification name and version
identified by the SpecificationID are consistent with the contents of
the ID; if a reader/receiver detects an inconsistency, it SHOULD
prefer the specification name and version derived from the content,
and SHOULD log the inconsistency so a human can correct the problem.
4.3.3. Vulnerability
A Vulnerability consists of an extension to the
Incident.Method.AdditionalData element with a dtype of "xml". The
extension describes the (candidate) vulnerabilities of incidents or
events.
It is recommended that Method class SHOULD contain one or more of the
extension elements whenever available.
A Vulnerability element is structured as follows.
+------------------------+
| Vulnerability |
+------------------------+
| STRING Version |<>--(0..*)--[ Record ]
| ENUM SpecificationID |<>--(0..*)--[ Reference ]
| STRING VulnerabilityID |<>--(0..*)--[ PlatformID ]
| |<>--(0..*)--[ Scoring ]
+------------------------+
Figure 5: Vulnerability class
This class has the following attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the Record element. The
value should be chosen from the IDs listed in Figure 1, such as
CVE_1.0 and CVRF_1.0. Note that the lists in Figure 1 will be
developed further by IANA.
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VulnerabilityID: OPTIONAL. STRING. An ID of a vulnerability to be
reported. This attribute SHOULD be used whenever such ID is
available, but could be omitted if no such ID is available. In
case Record or Reference elements are provided, writers/senders
MUST ensure that this ID is consistent with the one provided by
the Record or Reference elements; if a reader/receiver detects an
inconsistency, it SHOULD prefer the AttackPatternID, and SHOULD
log the inconsistency so a human can correct the problem.
This class is composed of the following aggregate classes.
Record: Zero or one. EM_XML. A complete document that is formatted
according to the specification and its version identified by the
value of the SpecificationID with the Figure 1.
Reference: Zero or one of iodef:Reference [RFC5070]. This element
allows an IODEF document to include a link to a structured
information instead of directly embedding it into a Record
element.
PlatformID: Zero or more. An identifier of software platform
affected by the vulnerability, which is elaborated in
Section 4.3.2. Some of the structured information may include
platform ids within it. In this case, the PlatformID element
SHOULD NOT be used since the Record element contains the platform
ids. If a reader/receiver detects platform ids in both Record and
PlatformID elements and their inconsistency, it SHOULD prefer the
platform ids derived from the Record element, and SHOULD log the
inconsistency so a human can correct the problem.
Scoring: Zero or more. An indicator of the severity of the
vulnerability, such as CVSS score, which is elaborated in
Section 4.3.4. Some of the structured information may include
scores within it. In this case, the Scoring element SHOULD NOT be
used since the Record element contains the scores. If a reader/
receiver detects scores in both Record and Scoring elements and
their inconsistency, it SHOULD prefer the scores derived from the
Record element, and SHOULD log the inconsistency so a human can
correct the problem.
4.3.4. Scoring
A Scoring class describes the scores of the severity in terms of
security. It is recommended that Vulnerability and Weakness classes
contain the elements whenever available.
A Scoring class is structured as follows.
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+----------------------+
| Scoring |
+----------------------+
| STRING Version |<>----------[ Score ]
| ENUM SpecificationID |
+----------------------+
Figure 6: Scoring class
This class has two attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. STRING. The ID of the specification and
its version specifying the format of the Score element. The value
should be chosen from the IDs listed in Figure 1, such as CVSS_2.0
and CWSS_0.8. Note that the lists in Figure 1 will be developed
further by IANA.
This class is composed of an aggregate class.
Score: One. EM_XML. Arbitrary information structured by the
specification identified by the specification and its version
identified by the value of the SpecificationID with the Figure 1.
Writers/senders MUST ensure the specification name and version
identified by the SpecificationID are consistent with the contents of
the Score; if a reader/receiver detects an inconsistency, it SHOULD
prefer the specification name and version derived from the content,
and SHOULD log the inconsistency so a human can correct the problem.
4.3.5. Weakness
A Weakness consists of an extension to the
Incident.Method.AdditionalData element with a dtype of "xml". The
extension describes the weakness types of incidents or events.
It is recommended that Method class SHOULD contain one or more of the
extension elements whenever available.
A Weakness element is structured as follows.
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+----------------------+
| Weakness |
+----------------------+
| STRING Version |<>--(0..*)--[ Record ]
| ENUM SpecificationID |<>--(0..*)--[ Reference ]
| STRING WeaknessID |<>--(0..*)--[ PlatformID ]
| |<>--(0..*)--[ Scoring ]
+----------------------+
Figure 7: Weakness class
This class has the following attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the Record element. The
value should be chosen from the IDs listed in Figure 1, such as
CWE_5.0. Note that the lists in Figure 1 will be developed
further by IANA.
WeaknessID: OPTIONAL. STRING. An ID of attack pattern to be
reported. This element SHOULD be used whenever such ID is
available, but could be omitted if no such ID is available. In
case Record or Reference elements are provided, writers/senders
MUST ensure that this ID is consistent with the one provided by
the Record or Reference elements; if a reader/receiver detects an
inconsistency, it SHOULD prefer the AttackPatternID, and SHOULD
log the inconsistency so a human can correct the problem.
This class is composed of the following aggregate classes.
Record: Zero or more. EM_XML. A complete document that is
formatted according to the specification and its version
identified by the value of the SpecificationID with the Figure 1.
Reference: Zero or one of iodef:Reference [RFC5070]. This element
allows an IODEF document to include a link to a structured
information instead of directly embedding it into a Record
element.
PlatformID: Zero or more. An identifier of software platform
affected by the weakness, which is elaborated in Section 4.3.2.
Some of the structured information may include platform ids within
it. In this case, the PlatformID element SHOULD NOT be used since
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the Record element contains the platform ids. If a reader/
receiver detects platform ids in both Record and PlatformID
elements and their inconsistency, it SHOULD prefer the platform
ids derived from the Record element, and SHOULD log the
inconsistency so a human can correct the problem.
Scoring: Zero or more. An indicator of the severity of the
weakness, such as CWSS score, which is elaborated in
Section 4.3.4. Some of the structured information may include
scores within it. In this case, the Scoring element SHOULD NOT be
used since the Record element contains the scores. If a reader/
receiver detects scores in both Record and Scoring elements and
their inconsistency, it SHOULD prefer the scores derived from the
Record element, and SHOULD log the inconsistency so a human can
correct the problem.
4.3.6. EventReport
An EventReport consists of an extension to the
Incident.EventData.Record.RecordData.RecordItem element with a dtype
of "xml". The extension embeds structured event reports.
It is recommended that RecordItem class SHOULD contain one or more of
the extension elements whenever available.
An EventReport element is structured as follows.
+----------------------+
| EventReport |
+----------------------+
| STRING Version |<>--(0..*)--[ Record ]
| ENUM SpecificationID |<>--(0..*)--[ Reference ]
+----------------------+
Figure 8: EventReport class
This class has the following attributes.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the Record element. The
value should be chosen from the IDs listed in Figure 1, such as
CEE_0.6 and XDAS_1998. Note that the lists in Figure 1 will be
developed further by IANA.
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This class is composed of three aggregate classes.
Record: Zero or one. EM_XML. A complete document that is formatted
according to the specification and its version identified by the
value of the SpecificationID with the Figure 1.
Reference: Zero or one of iodef:Reference [RFC5070]. This element
allows an IODEF document to include a link to a structured
information instead of directly embedding it into a Record
element.
This class MUST contain at least one of Record or Reference elements.
Writers/senders MUST ensure the specification name and version
identified by the SpecificationID are consistent with the contents of
the Record; if a reader/receiver detects an inconsistency, it SHOULD
prefer the specification name and version derived from the content,
and SHOULD log the inconsistency so a human can correct the problem.
4.3.7. Remediation
A Remediation consists of an extension to the Incident.AdditionalData
element with a dtype of "xml". The extension elements describes
incident remediation information including instructions.
It is recommended that Incident class SHOULD contain one or more of
this extension elements whenever available.
A Remediation class is structured as follows.
+----------------------+
| Remediation |
+----------------------+
| STRING Version |<>--(0..*)--[ Record ]
| ENUM SpecificationID |<>--(0..*)--[ Reference ]
+----------------------+
Figure 9: Remediation class
This class has an attribute.
Version: OPTIONAL. STRING. The version number of the extension
specification to which this class conforms. This value should be
1.00, to be compliant with this document. Its default value is
1.00.
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SpecificationID: REQUIRED. ENUM. The ID of the specification and
its version specifying the format of the Record element. The
value should be chosen from the IDs listed in Figure 1, such as
OVAL_5.10, OCIL_2.0, and XCCDF_1.2. Note that the lists in
Figure 1 will be developed further by IANA.
This class is composed of three aggregate classes.
Record: Zero or one. EM_XML. A complete document that is formatted
according to the specification and its version identified by the
value of the SpecificationID with the Figure 1.
Reference: Zero or one of iodef:Reference [RFC5070]. This element
allows an IODEF document to include a link to a structured
information instead of directly embedding it into a Record
element.
This class MUST contain at least one of Record or Reference elements.
Writers/senders MUST ensure the specification name and version
identified by the SpecificationID are consistent with the contents of
the Record; if a reader/receiver detects an inconsistency, it SHOULD
prefer the specification name and version derived from the content,
and SHOULD log the inconsistency so a human can correct the problem.
5. Examples
This section provides examples of an incident encoded in the IODEF.
These examples do not necessarily represent the only way to encode a
particular incident. [Note: this section will be thoroughly checked
later.]
5.1. Reporting an attack
An example of a CSIRT reporting an attack.
xsi:schemaLocation="urn:ietf:params:xml:schema:iodef-1.0">
189493
2001-09-13T23:19:24+00:00
Incident report in company xx
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[embed data in CAPEC format, if necessary]
http://capec.mitre.org/data/definitions/14.html
[embed data in CVE format]
[describe CVSS scores of the CVE entry]
[describe CPE ID relevant to the CVE entry]
[embed data in CWE format]
[describe CWSS scores of the CWE entry]
Example.com CSIRT
example-com
contact@csirt.example.com
192.0.2.200
57
192.0.2.16/28
80
CPE_2.3
[embed identifier in CPE format]
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2001-09-13T18:11:21+02:00
a Web-server event record
[embed data in CEE format]
2001-09-14T08:19:01+00:00
Notification sent to
constituency-contact@192.0.2.200
[embed OVAL-structured information here]
[embed XCCDF-structured information here]
Figure 10: Example UML Element Diagram
6. Security Considerations
This document specifies a format for encoding a particular class of
security incidents appropriate for exchange across organizations. As
merely a data representation, it does not directly introduce security
issues. However, it is guaranteed that parties exchanging instances
of this specification will have certain concerns. For this reason,
the underlying message format and transport protocol used MUST ensure
the appropriate degree of confidentiality, integrity, and
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authenticity for the specific environment.
Organizations that exchange data using this document are URGED to
develop operating procedures that document the following areas of
concern.
6.1. Transport-Specific Concerns
The underlying messaging format and protocol used to exchange
instances of the IODEF MUST provide appropriate guarantees of
confidentiality, integrity, and authenticity. The use of a
standardized security protocol is encouraged. The Real-time Inter-
network Defense (RID) protocol [RFC6045] and its associated transport
binding [RFC6046] provide such security.
The critical security concerns are that these structured information
may be falsified or they may become corrupt during transit. In areas
where transmission security or secrecy is questionable, the
application of a digital signature and/or message encryption on each
report will counteract both of these concerns. We expect that each
exchanging organization will determine the need, and mechanism, for
transport protection.
6.2. Using the iodef:restriction Attribute
In some instances, data values in particular elements may contain
data deemed sensitive by the reporter. Although there are no
general-purpose rules on when to mark certain values as "private" or
"need-to-know" via the iodef:restriction attribute, the reporter is
cautioned not to apply element-level sensitivity markings unless they
believe the receiving party (i.e., the party they are exchanging the
event report data with) has a mechanism to adequately safeguard and
process the data as marked.
7. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemata
conforming to a registry mechanism described in [RFC3688].
Registration request for the IODEF structured cybersecurity
information extension namespace:
URI: urn:ietf:params:xml:ns:iodef-sci-1.0
Registrant Contact: Refer here to the authors' addresses section
of the document.
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XML: None
Registration request for the IODEF structured cybersecurity
infomration extension XML schema:
URI: urn:ietf:params:xml:schema:iodef-sci-1.0
Registrant Contact: Refer here to the authors' addresses section
of the document.
XML: Refer here to the XML Schema in the appendix of the document.
Request for managing a namespace list: the schemata of the embedded
structured information are maintained outside of the IETF currently,
but the list of the embedded specifications' IDs and namespaces need
to be registered to IANA repository.
8. Acknowledgment
The following groups and individuals, listed alphabetically,
contributed substantially to this document and should be recognized
for their efforts.
Paul Cichonski, NIST
Black David, EMC
Robert Martin, MITRE
Kathleen Moriarty, EMC
Lagadec Philippe, NATO
Anthony Rutkowski, Yaana Technology
Brian Trammell, CERT/NetSA
9. Appendix: XML Schema Definition for Extension
The XML Schema describing the elements defined in the Extension
Definition section is given here. Each of the examples in Section 5
should be verified to validate against this schema by automated
tools. [Note: this section will be thoroughly checked later.]
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Example Schema Diagram
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident
Object Description Exchange Format", RFC 5070,
December 2007.
[RFC6045] Moriarty, K., "Real-time Inter-network Defense (RID)",
RFC 6045, November 2010.
[RFC6046] Moriarty, K. and B. Trammell, "Transport of Real-time
Inter-network Defense (RID) Messages", RFC 6046,
November 2010.
10.2. Informative References
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
July 2003.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[RFC6116] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to
Uniform Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)", RFC 6116,
March 2011.
[CVSS] Peter Mell, Karen Scarfone, and Sasha Romanosky, "The
Common Vulnerability Scoring System (CVSS) and Its
Applicability to Federal Agency Systems".
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[CAPEC] The MITRE Corporation, "Common Attack Pattern Enumeration
and Classification (CAPEC)".
[CEE] The MITRE Corporation, "Common Event Expression (CEE)".
[CPE] Brant A. Cheikes and David Waltermire and Karen Scarfone,
"Common Platform Enumeration: Naming Specificatino Version
2.3", 2011.
[CVE] The MITRE Corporation, "Common Vulnerability and Exposures
(CVE)".
[CVRF] ICASI, "http://www.icasi.org/cvrf".
[CWE] The MITRE Corporation, "Common Weakness Enumeration
(CWE)".
[CWSS] The MITRE Corporation, "Common Weakness Scoring System
(CWSS)".
[ISO/IEC 19770-2]
ISO/IEC, "Information technology -- Software asset
management -- Part 2: Software identification tag", 2009.
[OCIL] David Waltermire and Karen Scarfone and Maria Casipe, "The
Open Checklist Interactive Language (OCIL) Version 2.0",
2011.
[OVAL] The MITRE Corporation, "Open Vulnerability and Assessment
Language (OVAL)".
[XCCDF] David Waltermire and Charles Schmidt and Karen Scarfone
and Neal Ziring, "Specification for the Extensible
Configuration Checklist Description Format (XCCDF) version
1.2 (DRAFT)", 2011.
[XDAS] The Open Group, "Distributed Audit Service (XDAS),
Preliminary Specification", 1998.
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Authors' Addresses
Takeshi Takahashi
National Institute of Information and Communications Technology
4-2-1 Nukui-Kitamachi Koganei
184-8795 Tokyo
Japan
Phone: +80 423 27 5862
Email: takeshi_takahashi@nict.go.jp
Kent Landfield
McAfee, Inc
5000 Headquarters Drive
Plano, TX 75024
USA
Email: Kent_Landfield@McAfee.com
Thomas Millar
US CERT
Email: thomas.millar@us-cert.gov
Youki Kadobayashi
National Institute of Information and Communications Technology
4-2-1 Nukui-Kitamachi Koganei
184-8795 Tokyo
Japan
Phone: +80 423 27 5862
Email: youki-k@is.aist-nara.ac.jp
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