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 Takahashi, et al. Expires April 7, 2012 [Page 1] Internet-Draft IODEF-ext-sci Oct 2011 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 Takahashi, et al. Expires April 7, 2012 [Page 2] Internet-Draft IODEF-ext-sci Oct 2011 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: Takahashi, et al. Expires April 7, 2012 [Page 3] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 4] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 5] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 6] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 7] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 8] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 9] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 10] Internet-Draft IODEF-ext-sci Oct 2011 +----------------------+ | 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. Takahashi, et al. Expires April 7, 2012 [Page 11] Internet-Draft IODEF-ext-sci Oct 2011 +----------------------+ | 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 Takahashi, et al. Expires April 7, 2012 [Page 12] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 13] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 14] Internet-Draft IODEF-ext-sci Oct 2011 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 Takahashi, et al. Expires April 7, 2012 [Page 15] Internet-Draft IODEF-ext-sci Oct 2011 [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
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192.0.2.16/28
 80 CPE_2.3 [embed identifier in CPE format] Takahashi, et al. Expires April 7, 2012 [Page 16] Internet-Draft IODEF-ext-sci Oct 2011 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 Takahashi, et al. Expires April 7, 2012 [Page 17] Internet-Draft IODEF-ext-sci Oct 2011 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. Takahashi, et al. Expires April 7, 2012 [Page 18] Internet-Draft IODEF-ext-sci Oct 2011 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.] Takahashi, et al. Expires April 7, 2012 [Page 20] Internet-Draft IODEF-ext-sci Oct 2011 Takahashi, et al. Expires April 7, 2012 [Page 21] Internet-Draft IODEF-ext-sci Oct 2011 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". Takahashi, et al. Expires April 7, 2012 [Page 22] Internet-Draft IODEF-ext-sci Oct 2011 [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. Takahashi, et al. Expires April 7, 2012 [Page 23] Internet-Draft IODEF-ext-sci Oct 2011 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 Takahashi, et al. Expires April 7, 2012 [Page 24]