INCH Working Group Yuri Demchenko Internet Draft University of Amsterdam Category: Informational Hiroyuki Ohno Expires: February 6, 2006 WIDE Project Roman Danyliw CERT/CC Glenn M Keeni Cyber Solutions Inc. September 7, 2005 Requirements for the Format for INcident information Exchange (FINE) Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This document is a product of the inch Working Group. Comments should be addressed to the authors or the mailing list at inch@nic.surfnet.nl This Internet-Draft will expire on February 6, 2006 Copyright Notice Expires: February 6, 2006 [Page 1] Internet Draft September 7, 2005 Copyright (C) The Internet Society (2005). All Rights Reserved. Abstract The purpose of the Format for Incident report Exchange (FINE) is to facilitate the exchange of incident information among Computer Security Incident Response Teams (CSIRTs) and involved parties. A common and well-defined format will help in the exchange of Incident related information across organizations, regions and countries. FINE will also be useful for reactionary analysis of current security incidents and proactive identification of trends that can lead to incident prevention. This document describes the high-level functional requirements for an Incident Report Exchange Format. Table of Contents 1. Introduction ............................................... 3 2. Incident Handling Framework ................................ 3 3. General Requirements ....................................... 5 4. Format Requirements ........................................ 6 5. Communication Mechanism Requirements ....................... 7 6. Content Requirements ....................................... 7 7. Security Considerations .................................... 8 8. IANA Considerations ........................................ 8 9. References ................................................. 9 10. Acknowledgements ........................................... 10 11. Authors' Addresses ......................................... 10 Full Copyright Statement ....................................... 11 Appendix: History of Changes Expires: February 6, 2006 [Page 2] Internet Draft September 7, 2005 1. Introduction Computer security incidents occur across administrative domains, often spanning different organizations and national borders. Hence, a response requiring coordination and collaboration between the involved parties and the responsible Computer Security Incident Response Teams (CSIRTs) is often required. The basis for this interaction is often the various data and statistics describing the nature of the incident. This information, referred to as an incident report in this document, supports response activity to the specific incident, but may also be used for historical analysis or proactive responses. This document defines the high-level functional requirements for a format that would support the exchange of incident reports. The abstract format being discussed is referred to as the Format for INcident report Exchange (FINE). The implementation of the requirements, the format itself is not provided in this document. The intent of FINE is to enable quick and effective response to incidents by improving the ability of CSIRTs to exchange and process incident reports. This will be achieved by ensuring that FINE + makes the semantics of the report unambiguous; + ensures the data has a well defined syntax; and + supports easy categorization and statistical analysis. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, RFC 2119 [RFC2119]. 2. Incident Handling Framework 2.1. Descriptive Terms For the purpose of clarity, certain commonly used terms from the operational domain of CSIRTs are defined here. These are based on related documents [7, 8, 9, 10, 11] 2.1.1. Event An event is an occurrence in a system or network that may be of interest and warrant attention. An event is not necessarily malicious or deliberate. 2.1.2. Attack An attack is a series of events caused either directly or indirectly by a source that violates the security policy of the target. These violations may include a compromise of a user account, denial-of- service, information theft, etc. Expires: February 6, 2006 [Page 3] Internet Draft September 7, 2005 2.1.3. Source The origin of an attack as described by a host, user account, computer program, network address, person, or organization. 2.1.4. Target The target of an attack as described by a host, user account, computer program, network address, person, or organization. 2.1.5. Computer security incident A computer security incident, referred to as incident, is a set of one or more related attacks identified by a CSIRT. 2.1.6. Incident Report An incident report is the collection of information describing an incident. 2.1.7. CSIRT A Computer Security Incident Response Team, CSIRT, is an individual or a group of individuals that has the responsibility to coordinate and support the response to incidents in a defined constituency [7]. A CSIRT creates, receives, processes and maintains incident reports. 2.1.8. Impact An impact describes the consequence of an incident on a target expressed in terms relevant to a user community. 2.2 The Operational Model Incident reports are an important subset of information exchanged between a CSIRT and its constituency or other CSIRTs. These reports form the basis for resolving and understanding activity in a constituency. A CSIRT may create an incident report when an incident is reported; or may receive incident reports from, and send them to, other CSIRTs. As analysis is performed and investigation progresses, more information about an incident may be discovered causing updates to previously sent incident reports to be exchanged. The creation and exchange of incident reports is often driven by a work-flow process that prioritizes and manages the information flow in the CSIRT. These systems often associate CSIRT personnel with particular incidents or maintain status onto a particular investigation. FINE does not provide a representation for these internal processes. FINE is a representation for the data exchanged between external parties. In order to integrate FINE into CSIRT operations, entities will have to use an interface to convert to and from the internal Expires: February 6, 2006 [Page 4] Internet Draft September 7, 2005 data representation (of a propriety work-flow application or database for the incident report) and FINE. Hence, the sender of an incident report must convert from the local format to FINE, while the recipient must translate FINE back into its own local format. The communicating CSIRTs need not have the same local format for storing incident reports. This information exchange is depicted in Figure 1. CSIRT CSIRT +------------------+ +------------------+ | | | | | +--------+ +---------+ +---------+ +--------+ | | | |<--|Interface|<--Incident-->|Interface|-->| | | | |Incident| +---------+ Report +---------+ |Incident| | | | Report | | | | Report | | | |Database| | |=== FINE ===| | |Database| | | | | | | | | | | +--------+ | | +--------+ | | | | | +------------------+ +------------------+ Fig. 1 Operational Model for FINE 3. General Requirements 3.1 FINE SHALL reference and use previously published RFCs where possible. 3.2 FINE MUST have well defined semantics and provide a standard mechanism for extensibility. The data elements of the various components of FINE should be typed, and the meaning should be well specified. Likewise, there should be a standardized method to address representing data not defined in the data model. 4. Format Requirements 4.1 FINE SHALL support full internationalization and localization. A significant part of the incident report may comprise of natural language text. Since some incidents may involve CSIRTs from different countries and geographic regions, FINE must have provisions for using Expires: February 6, 2006 [Page 5] Internet Draft September 7, 2005 local character sets and encodings. In cases where local (non-standard) character sets and encodings are used, the data elements that carry encoding-sensitive information should be clearly indicated. Furthermore, it should be possible to preserve the content of these elements when transferring an incident report. 4.2 FINE MUST allow multilingual reports. Different parts of the incident report may be written in a different natural language. Furthermore, FINE must support multiple translations of the same part of a report. 4.3 FINE MUST support aggregation and filtering of incident report data. The structure of the FINE data elements and their associated semantics must support aggregation and filtering. 4.4 FINE MUST be able to document the evolution of an incident. An incident report may evolve with time as further investigation is carried out on the incident. Earlier information may be modified and new information may be added. FINE must support the documentation of these changes. 4.5 FINE MUST support specifying a granular access restriction policy on subsets of the incident report. Various parts of an incident report will have information of varying degrees of sensitivity and will need to be handled with the appropriate level of confidentiality. It must be possible to specify the degree of confidentiality for subsets of the incident report. With this information applications can then implement different levels of access restrictions for the different components of the incident report. 4.6 FINE SHOULD allow the application of external mechanisms to support authenticity, integrity, and non-repudiation checks of incident reports. FINE itself need not guarantee authenticity, integrity, or non- repudiation. However, the specification must detail a standardized mechanism to ensure these properties. Expires: February 6, 2006 [Page 6] Internet Draft September 7, 2005 5. Communication Mechanism Requirements 5.1 The communication mechanisms MUST NOT solely be used to ensure the security of a FINE incident report. Incident report exchange will normally be conducted using standard communication protocols and exchange mechanisms, for example, e-mail, HTTP, FTP, XML Web Services, etc. FINE must not rely on communication mechanisms or specific applications to ensure authenticity, integrity and/or confidentiality of an incident report. Provisions for authenticity, integrity and confidentiality should be made in FINE. 6. Content Requirements 6.1 FINE MUST be flexible enough to support various degrees of completeness, while still clearly defining the minimal information required for describing an incident. 6.2 FINE MUST support globally unique identifiers for each incident report. It should be possible to reference an incident report unambiguously using a globally unique identifier. Furthermore, it should be possible to derive the creator of the incident report from this identifier. 6.3 FINE MUST support the naming of the source and target. 6.4 FINE MUST support the description of various aspects of the source and target. 6.5 FINE MUST support the description of the methodology used by the attacker. Well-known classifications or enumeration schemes should be used to describe the attack that caused the incident. 6.6 FINE SHOULD support the identification of the creator of the incident report. FINE should indicate the source of each component of the incident report if it is different from the creator (e.g., the team handling the incident). 6.7 FINE SHOULD support the inclusion or referencing of information external to the incident report. Expires: February 6, 2006 [Page 7] Internet Draft September 7, 2005 6.8 FINE MUST support natural language descriptions of the incident. 6.9 FINE SHOULD support references to the appropriate advisories from coordination and analysis centers. 6.10 FINE SHOULD support a description of the impact of the incident. 6.11 FINE SHOULD support a description of the actions taken during the course of handling the incident. 6.12 FINE MUST use a standardized time specification. Incident reports should represent time in such a way that it is possible to easily compare information reported from different timezones. Different systems will support different time granularities. FINE should be able to support incident reports from various systems irrespective of their time granularity. 7. Security Considerations There are no explicit security considerations for this document since no protocol or information model is specified. However, a number of security relevant requirements are outlined for FINE implementers. By its nature, FINE will represent sensitive information. Hence, implementers should ensure support for access restriction (requirement 4.5); transport agnostic security guarantees (requirement 5.1); and confidentiality, integrity, and non- repudiation (requirement 4.6). 8. IANA Considerations This document requires no action from IANA. 9. References 9.1 Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 9.2 Informative References [2] Arvidsson, J., Cormack, A., Demchenko, Y. and Meijer J., Expires: February 6, 2006 [Page 8] Internet Draft September 7, 2005 "TERENA's Incident Object Description and Exchange Format Requirements", RFC 3067, February 2001 [3] Danyliw, R., Meijer, J. and Demchenko, Y., "Incident Object Description and Exchange Format Data Model and Extensible Markup Language (XML) Document Type Definition", work in progress (currently ). [4] Taxonomy of the Computer Security Incident related terminology - http://www.terena.nl/task-forces/tf-csirt/iiodef/docs/i- taxonomy_terms.html [5] Wood, M., "Intrusion Detection Exchange Format Requirements", work in progress (currently ). [6] Brezinski, D., Killalea, T., "Guidelines for Evidence Collection and Archiving". BCP 55, RFC 3227, February 2002. [7] Brownlee, N. and E. Guttman, "Expectations for Computer Security Incident Response", BCP 21, RFC 2350, June 1998. [8] Shirey, R., "Internet Security Glossary", FYI 36, RFC 2828, May 2000. [9] "Establishing a Computer Security Incident Response Capability (CSIRC)", NIST Special Publication 800-3, November 1991 [10] West-Brown, M., Stikvoort, D., Kossakowski, K., Killcrece G., Ruefle, R., Zajicek, M., "Handbook for Computer Security Incident Response Teams (CSIRTs)", CMU/SEI-98-HB-002, Carnegie Mellon University, Pittsburgh, PA, April 2003. [11] Howard, J. and Longstaff, A., "A Common Language for Computer Security Incidents", Sandia Report: SAND98-8667, Sandia National Laboratories, October 1998. Expires: February 6, 2006 [Page 9] Internet Draft September 7, 2005 10. Acknowledgments. The precursor of this document is "RFC3067 TERENA's Incident Object Description Exchange Format Requirements" [2] which is based on the work done at Incident Object Description Exchange Format Working Group at TERENA. Subsequent work and discussion have been carried out in the INCH-WG and in the WIDE-WG on Network Management and Security. The following individuals, in alphabetic order, have made substantial contribution to this document Hiroyuki Kido Kathleen M. Moriarty 11. Authors' Addresses: Yuri Demchenko University of Amsterdam, The Netherlands Email: demch@chello.nl Hiroyuki Ohno WIDE Project, Japan Email: hohno@wide.ad.jp Roman Danyliw CERT Coordination Center 4500 Fifth Ave. Pittsburgh, PA 15213 USA Email: rdd@cert.org Glenn Mansfield Keeni Cyber Solutions Inc. Sendai, Japan Email: glenn@cysols.com Expires: February 6, 2006 [Page 10] Internet Draft September 7, 2005 Full Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Expires: February 6, 2006 [Page 11] Internet Draft September 7, 2005 Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Expires: February 6, 2006 [Page 12] Internet Draft September 7, 2005 Appendix - non-normative. Major Changes (reverse count) Information about changes to the document since publishing -00 version will be documented here. Major changes in version-05 1) In 2.1 the definitions have been rearranged. Incident Report (earlier 2.1.8 have been moved to 2.1.6) 2) Section 2.2, Operational model, revised 3) Editorial nits 4) IDnits 5) Added Roman Danyliw to the authors list. Major changes in version -04 1) Operational model rewritten 2) Editorial nits 3) IPR notice updated Major changes in version -03 (Second revision) 1) title changed to Requirements for the Format for INcident information Exchange (FINE) 2) editorial nits 3) RFC2119 key words used 4) added description to 4.6 5) reformatted 4.7 and 5.1 to have single statement requirements followed by description of the requirements. 6) added an example to 4.2 7) moved 6.13 to Format requirements as 4.8 8) updated references #3, #5, #10 9) updated section 2.2 Major changes in version -03 (First revision) 1) editorial nits 2) in Security Considerations section an example is added to explain the impact of the contents of the IR on the security and privacy of individuals of organization. 3) Section 3 is deleted Major changes in version -02 1) clarified definitions of some terms. Added a few definitions. 2) in 5.1, added requirement for handling non-standard/local encoding and/or character codes. 3) in 5.7, added requirement that multiple versions of the report Expires: February 6, 2006 [Page 13] Internet Draft September 7, 2005 should be consistent 4) in 7.5, added requirement that the source of each component of the Incident report must be identified (if different from the creator of the Incident report). 5) some editorial nits are fixed. Major changes in version -01 1) clarified definition of some terms - still in the process, needs more discussion with concerned parties. 2) re-written section 2. Operational model 3) added text about multilingual support for non-utf-8 character sets to item "5.1 FINE shall support full internationalization and localization" - results of discussion at IETF-56 4) included clear statement about unique identification of the Incident report to item "5.1 FINE shall support full internationalization and localization." 5) added item about the possibility of Incident description in natural language: 7.7 The FINE may contain a description of the Incident or comprising security events in a natural language. 6) requirement about describing impact of the Incident extended (item 7.9) with recommendation to provide guidelines to describe the impact on the target to ensure a uniform interpretation of the description. 7) item 7.11 about time normalization extended with the possibility to describe time offset when normalization is not possible. Expires: February 6, 2006 [Page 14]