Network Working Group Yuri Demchenko INTERNET DRAFT NLnet Labs Category: Informational Hiroyuki Ohno WIDE Project Expires December 2003 Glenn M Keeni Cyber Solutions Inc. June, 2003 Requirements for Format for INcident Report Exchange (FINE) Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 obsolete 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/ietf/lid-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract The purpose of the Format for INcident report Exchange (FINE) is to facilitate the exchange of incident information and statistics among responsible Computer Security Incident Response Teams (CSIRTs) and involved parties for reactionary analysis of current intruder activity and proactive identification of trends that can lead to incident prevention. A common and well-defined format will help in exchanging, retrieving and archiving Incident related information across organizations, regions and countries. [Page 1] INTERNET DRAFT FINE Requirements June, 2003 This document describes the requirements for an Incident Report Exchange Format. 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 RFC 2119 [1]. Table of Contents 1. Introduction ............................................... 2 2. Incident Handling Framework ................................ 2 3. The Goal ................................................... 7 4. General Requirements ....................................... 8 5. Format Requirements ........................................ 8 6. Communication Requirements ................................. 9 7. Content Requirements ....................................... 9 8. Security Considerations .................................... 11 9. Acknowledgements ........................................... 12 10. References ................................................. 12 11. Authors' Addresses ......................................... 13 Full Copyright Statement ....................................... 13 1. Introduction Computer security incidents occur across administrative domains often spanning different organizations and national borders. Therefore, the exchange of incident information and statistics among involved parties and the responsible Computer Security Incident Response Teams (CSIRTs) is crucial for both reactionary analysis of current intruder activity and proactive identification of trends that can lead to incident prevention. In the following we refer to the information pertaining to an incident as an Incident Report. To facilitate the incident related information exchange a common well defined format is needed. This document defines the high-level functional requirements of a Format for INcident report Exchange (FINE). 2. Incident Handling Framework 2.1. Incident Description Terms In the following we define the main terms used in this document. There are based on current definitions in related documents [7, 8, 9, 10, 11]. Expires December 2003 [Page 2] INTERNET DRAFT FINE Requirements June, 2003 2.1.1. Attack An assault on system security that derives from an intelligent threat, i.e., an intelligent act that is a deliberate attempt (especially in the sense of a method or technique) to evade security services and violate the security policy of a system. An Attack can be active, passive. It may be perpetrated by an insider, an outsider or, via an attack mediator. 2.1.2. Attacker Attacker is individual who attempts one or more attacks. For the purpose of FINE, an attacker is described by the computer/network ID, from which the attack was launched. The organisation name and/or physical location of the computer/network are used as additional information. 2.1.3. CSIRT CSIRT (Computer Security Incident Response Team) is a team that coordinates and supports the response to security incidents that involve sites within a defined constituency [7]. The CSIRT generates, processes and maintains incident reports. 2.1.4. Damage The intended or unintended consequence of an attack. Description of damage may include free text description of actual result of attack, and, where possible, structured information about the particular damaged system, subsystem or service. 2.1.5. Event An action directed at a target, which is intended to result in a change of state (status) of the target. From the point of view of event origination, it can be defined as any observable occurrence in a system or network, which resulted in an alert being generated. For example, three failed logins in 10 seconds might indicate a brute- force login attack. 2.1.6. Impact Impact describes result of attack expressed in terms of user community, for example the cost in terms of financial or other disruption 2.1.7. Computer/Network Security Incident A Computer/Network Security Incident, referred to as incident in this work, is any adverse event (or group of events) wherein an attempt Expires December 2003 [Page 3] INTERNET DRAFT FINE Requirements June, 2003 has been made, successfully or otherwise, to compromise some aspect of computer system or network security. Typical computer security incidents are: a computer intrusion, a denial-of-service attack, information theft or data manipulation, etc. 2.1.8. Incident Report In this document an Incident Report refers to the information pertaining to an incident. In practice, Incident Report may have internal proprietary format that is adapted to local Incident handling procedure and used Incident Handling System (IHS). Definition of the requirements to the format for Incident Report exchange is the subject of this document. 2.1.9. Target The target of an attack. This can be a logical entity( e.g. a user account, a computer process or data, a logical network or internetwork) or a physical entity, e.g. (a computer interface, a router etc.) 2.1.10. Victim The entity which suffered the attack. For the purpose of FINE victim is described by its network ID, organisation and location information. 2.1.11. Other terms Other terms used: alert, activity, IDS, Security Policy, etc., - are defined in related I-Ds, RFCs and standards [2, 3, 6, 7, 8, 9, 10]. 2.2 The Operational Model Incident Reports are generated, received and updated. For example, An organization may send an Incident Report to a CSIRT when an attack has been detected. Computer Security Incident Response Teams (CSIRTs) receive Incident Reports from customers, or from other CSIRTs. The CSIRTs maintain these reports. They may process the reports to generate statistics, or investigate the Incident further. As part of the investigation, or as part of the reporting the CSIRT may forward the Incident Report or parts of it to other CSIRTs. The CSIRTs may also receive results of investigation, or additional information related to currently active Incident from other CSIRTs. These operations are shown in fig. 1 Expires December 2003 [Page 4] INTERNET DRAFT FINE Requirements June, 2003 +----- CSIRT | +---------------------+ | | | | | +--------+ | | | | | | | | | | | Incident Report | | |Incident|<---------|<----------------->| Customers/ | |ReportDB| | | CSIRTs/ | | |<---+ |<=== FINE ===>| Other Org | | | | | | | | | +------+ | | | +--------+ |Stats | | | | | |Pkg | | | | | +-+--+-+ | | | | | | | | | +--------+ | | | +---------------------+ | | | V | Alerts, Reports | Statistics | +----- Fig. 1 Operational Model for FINE From the operational point of view during the life-cycle of an Incident Report the following may apply: + the report itself evolves; + the report is exchanged between CSIRTs and may be investigated/processed by multiple CSIRTs, simultaneously; + the changes in the report may be effected by one or more CSIRTs; + a single CSIRT may not be in a position to vouch for the veracity of all parts of the Incident Report; + the Incident Report may exist in several states: - handling û Incident is being handled - complete/closed - the Incident Report is not being processed and no processing is planned - waiting - the Incident Report is waiting on some event; From the content point of view and due to the nature of operations the following should be also considered for defining requirements to FINE: + 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. + Incident Report may be multilingual i.e. different parts of the Incident Report may use different languages. It is also possible that multiple versions of parts of the report exist, each version in a different language. The versions may not be consistent. Expires December 2003 [Page 5] INTERNET DRAFT FINE Requirements June, 2003 3. The Goal The purpose of the Format for INcident Report Exchange (FINE) is to facilitate the exchange of incident information and statistics among involved parties and Computer Security Incident Response Teams (CSIRTs) for reactionary analysis of current security incidents and proactive identification of trends that can lead to incident prevention. A common and well-defined format for Incident Reports will help in exchanging, retrieving and archiving Incident related information across organizations, regions and countries. The goal of the FINE format is + to make the semantics of the report as clear and unambiguous as possible, intended for use across organizational, regional and national boundaries; + to ensure that the report (or parts of it) has a well defined syntax; + to ensure that the structure of the report allows easy categorization and statistical analysis; + to ensure the verifiability of the integrity of the report, a the authenticity of the report source. 4. General Requirements 4.1 The definition of the Format for INcident Report Exchange (FINE) shall reference and use previously published RFCs where possible. 5. Format Requirements 5.1 FINE shall support full internationalization and localization. A significant part of the Incident Report will comprise of human- readable text. Since some Incidents need involvement of CSIRTs from different countries and geographic regions, FINE must have provisions so that the Incident Report can be presented in the local language in accordance with local rules and conventions. FINE must have provisions to specify the naming rules and conventions that have been applied in the Incident Report. In cases where the messages contain text strings and names that need characters other than Latin-1 (or ISO 8859-1), the information should preferably be represented using the ISO/IEC IS 10646-1 character set and encoded using the UTF-8 transformation format, and optionally using local character sets and encodings. In case when Incident information/data is received by party that may not correctly display and process other encoding than UTF-8, or information is exchanged between parties that priory known may not process correctly non-native (but other than UTF-8) encoding, the elements that can carry encoding sensitive information should marked with the special attribute and/or necessary transformation should be Expires December 2003 [Page 6] INTERNET DRAFT FINE Requirements June, 2003 applied. Use of this attribute can be initiated by sending party, or re-sending party that wants to preserve the specific content. 5.2 FINE must support aggregation and filtering of Incident Report data. The format of FINE must be structured with components that have a well-defined syntax and semantics. 5.3 FINE must provide the possibility for recording the evolution of an Incident Report during its lifetime. An Incident Report may evolve with time. As investigation proceeds, it is likely that more information about an incident will be revealed and parts of the earlier information will be modified/deleted. FINE must support the recording of these changes. changes with the level of details defined by internal/adopted Incident Handling procedure. 5.4 FINE must support the application of an access restriction policy to individual components of the Incident Report. An Incident Report may contain sensitive information. It must be possible to specify the degree of confidentiality for the individual components of the Incident Report. Applications can then implement different levels of access restrictions, for the different components of the Incident Report. 5.5 FINE report must be globally uniquely identifiable. It should be possible to refer to an Incident Report unambiguously using the globally unique identifier. It should also be possible to map the origin/creator of an Incident Report from its globally unique identifier. 5.6. The Format for Incident report Exchange itself must be extensible. The extension will be in terms of addition of components and/or extending the components. 6. Communication Mechanisms Requirements 6.1 The communication mechanisms must have no bearing on the authenticity, integrity, and confidentiality of a FINE formatted Incident Report. Provisions for authenticity, integrity and confidentiality should be made in FINE. 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. Expires December 2003 [Page 7] INTERNET DRAFT FINE Requirements June, 2003 7. Content Requirements 7.1 FINE must be flexible enough to support various degrees of completeness. At the same time it must clearly state the minimal information without which the information in the Incident Report will be seriously degraded. 7.2 FINE must contain information about the various entities involved in the incident. An Incident Report will generally refer to one or more entities. The entity may be the attacker, perpetrator, victim, or an observer. 7.3 FINE should support the description of various aspects/details of the entities involved in the incident. There may be several facets of an entity involved in an Incident Report. The entity may have zero or more network addresses and names as well as zero or more location names, organizational names, person names, machine names etc.. 7.4 FINE should contain the description of the method how the attack or security event was conducted if it is known. Well-known classification/enumeration schemes should be used to describe the type of attack or vulnerabilities and exposures caused particular Incident or security Event. 7.5 FINE must include the identity of the creator (or current owner) of the Incident Report (CSIRT or other authority). This may be the sender in an information exchange or the team currently handling the incident. 7.6 FINE should contain reference to advisories corresponding to the Incident Report, e.g. CERT/CC, CVE, and others. 7.7 The FINE may contain a description of the Incident or comprising security events in a natural language. 7.8 FINE should provide the possibility to include or reference additional detailed information/data related to the specific underlying event(s)/activity. This information may include IDMEF [5] messages, which have been generated by security devices. 7.9 FINE should provide the possibility for describing the impact of an incident. There should be guidelines to describe the impact on the target to ensure a uniform interpretation of the description. 7.10 The Incident Report should describe the actions taken since the occurrence of the incident. 7.11 Time shall be reported as the local time and time zone offset from UTC. (Note: See RFC 1902 for guidelines on reporting time.) Expires December 2003 [Page 8] INTERNET DRAFT FINE Requirements June, 2003 Internal Incident Report may contain local presentation of time related information, however FINE must support unambiguous time specification. In case when normalization of the time information is not possible (like in case of referencing additional data about the Incident that cannot be changed, e.g. timestamped log data), the time offset should be mentioned. 7.12 FINE will not have any specific requirement for granularity of time. Different systems will support different time granularities. FINE should be able to support Incident Reports from various systems irrespective of their time granularity. 7.13 FINE should allow the application of external mechanisms to support authenticity, integrity and non-repudiation checks of Incident Reports. 7.14 FINE must have a well defined semantics. 8. Security Considerations This memo does not describe a protocol by itself. This memo describes the requirements for an Incident Report Exchange Format. The reports themselves are about security incidents. The contents of the Incident Reports will have significant direct and/or indirect impact on the security and privacy of a network and/or individuals. FINE implementers should take care to analyze and implement the requirements stated in 5.5 and 7.12. 9. Acknowledgments. The precursor of this document is "RFC3067 TERENAÆs 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 has been carried out in the INCH-WG and in the WIDE-WG on Network Management and Security. 10. References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [2] Arvidsson, J., Cormack, A., Demchenko, Y., Meijer J. "TERENA's Incident Object Description and Exchange Format Requirements", RFC 3067, February 2001 Expires December 2003 [Page 9] INTERNET DRAFT FINE Requirements June, 2003 [3] Incident Object Description and Exchange Format Data Model and Extensible Markup Language (XML) Document Type Definition û October 2002. Work in progress. [4] Taxonomy of the Computer Security Incident related terminology - http://www.terena.nl/task-forces/tf-csirt/iiodef/docs/i- taxonomy_terms.html [5] Intrusion Detection Exchange Format Requirements by Wood, M. - October 2002, Work in Progress. [6] Guidelines for Evidence Collection and Archiving by Dominique Brezinski, Tom Killalea û 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] Handbook for Computer Security Incident Response Teams (CSIRTs), Moira J. West-Brown, Don Stikvoort, Klaus-Peter Kossakowski. - CMU/SEI-98-HB-001. - Pittsburgh, PA: Carnegie Mellon University, 1998. [11] A Common Language for Computer Security Incidents by John D. Howard and Thomas A. Longstaff. - Sandia Report: SAND98-8667, Sandia National Laboratories - http://www.cert.org/research/taxonomy_988667.pdf 11. AuthorsÆ Addresses: Yuri Demchenko NLnet Labs, The Netherlands Email: demch@chello.nl Hiroyuki Ohno WIDE Project, Japan Email: hohno@wide.ad.jp Glenn Mansfield Keeni Cyber Solutions Inc. Sendai, Japan Email: glenn@cysols.com Expires December 2003 [Page 10] INTERNET DRAFT FINE Requirements June, 2003 Full Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Appendix û non-normative Major Changes (reverse count) Information about changes to the document since publishing û00 version will be documented here. Major changes in version û01 1) clarified definition of some terms û 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 ô5.1 FINE shall support full internationalization and localizationö û results of discussion at IETF-56 4) included clear statement about unique identification of the Incident Report to item ô5.1 FINE shall support full internationalization and localization.ö 5) added item about the possibility of Incident description in natural language: Expires December 2003 [Page 11] INTERNET DRAFT FINE Requirements June, 2003 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 December 2003 [Page 12]