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INCH Working Group                                       Yuri Demchenko
Internet Draft                                  University of Amsterdam
Category: Informational                                   Hiroyuki Ohno
                                                           WIDE Project
Expires: August 6, 2005                                   Glenn M Keeni
                                                   Cyber Solutions Inc.

                                                       Fenruary 7, 2005

  Requirements for the Format for INcident information Exchange (FINE)

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   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.  FINE can be used 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 the exchange of Incident related information across
   organizations, regions and countries.  This document describes the
   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

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1. Introduction

   Computer security incidents occur across administrative domains,
   often spanning different organizations and national borders.  Hence,
   a distributed response requiring coordination and collaboration
   between the involved parties and the responsible Computer Security
   Incident Response Teams (CSIRTs) are often required to respond to
   these threats.  The basis for this interaction is 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 inform historical
   analysis or proactive responses.

   This document merely defines the high-level functional requirements
   for a transport format to exchange incident reports.  This abstract
   data representation, the Format for INcident report Exchange (FINE),
   is not specified.

   The intent of FINE is to decrease the response time to incidents and
   facilitate by improving the ability of  CSIRTs to process incident
   reports.  The definition of a well-defined format will facilitate the
   exchange of incident reports across organizations, regions and
   countries by achieving these particular goals:
      +  to make the semantics of the report as clear and unambiguous;
      +  to ensure that the data 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,
         and the authenticity of the report source.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "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 may or may not be malicious
   or deliberate.

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2.1.2. Attack
   An attack is a series of events caused either directly or indirectly
   by a source that violates a security policy of the target.  These
   violations may include a compromise of a user account, denial-of-
   service, information theft, etc.

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. CSIRT
   A Computer Security Incident Response Team, CSIRT, is an individual
   or a group of individuals that coordinate and support the response to
   incidents in a defined constituency [7]. A CSIRT creates, processes,
   and maintains incident reports.

2.1.7. Impact
   An impact describes the consequence of an incident on a target
   expressed in terms relevant to a user community.

2.1.8. Incident Report
   An incident report is the collection of the information describing an

2.2 The Operational Model

   Incident reports are generated, received and updated. For example, an
   organization may send an incident report to a Computer Security
   Incident Response Team (CSIRT) when an attack is detected. CSIRTs
   receive incident reports from customers or from other CSIRTs. The
   CSIRTs maintain these reports in an Incident Report Database in some
   format that may be specific to the CSIRT. The CSIRTs may process the
   reports to generate statistics, or investigate an 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 incidents from other CSIRTs.
   In the context of FINE, the incident reports will be handled by a
   CSIRT via an interface that is capable of converting a FINE formatted

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   incident report into the internal format used by the CSIRT and vice

These operations are shown in fig. 1

   +------------------+                          +------------------+
   |                  |                          |                  |
   | +--------+   +---------+              +---------+   +--------+ |
   | |        |<--|Interface|<--Incident-->|Interface|-->|        | |
   | |Incident|   +---------+    Report    +---------+   |Incident| |
   | | Report |       |                          |       | Report | |
   | |Database|       |     |===  FINE  ===|     |       |Database| |
   | |        |       |                          |       |        | |
   | +--------+       |                          |       +--------+ |
   |                  |                          |                  |
   +------------------+                          +------------------+

                   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. It may exist in one of the following
      - handling - the incident report is being handled
      - complete/closed - the incident report has been processed
        and no further processing is planned
      - waiting - the incident report is waiting on some event;

   + the report is exchanged between CSIRTs and may be
     investigated/processed by multiple CSIRTs, simultaneously;

   + additions and/or changes to the report may be made by one or
     more CSIRTs. Therefore, a single CSIRT may not be in a position
     to vouch for the veracity of all parts of the incident report.

3. General Requirements

3.1 FINE SHALL reference and use previously published RFCs where

3.2 FINE MUST have well defined semantics and provide a standard

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   mechanism for extensibility.

   The values of the various components of FINE should be typed, and the
   meaning should be well specified.  Likewise, there should be a
   standardized method to deal with the 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 will be comprised of human
   readable text. Since some incidents will entail involvement of CSIRTs
   from different countries and geographic regions, FINE must have
   provisions for using local character sets and encodings.

   In cases where local (non-standard) character sets and encodings are
   used, the elements that carry encoding sensitive information should
   be clearly indicated. 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
   language.  Likewise, multiple versions of the same part of the report
   may exist,  each in a different language.

4.3 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. For example, an application may
   want to generate the number of 'scan's that originated from a given
   network. FINE must support such filtering and aggregation.

4.4 FINE MUST be able to document the evolution of an incident.

   An incident report may evolve with time,  as further investigation is
   performed on the incident report.  Earlier information may be
   modified and new information may be added.  FINE must support the
   recording of these changes.

4.5 FINE MUST support specifying a granular access restriction policy
   for the specific elements 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 the individual components of the

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   incident report. Applications can then implement different levels of
   access restrictions for the different components of the incident

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.

5. Communication Mechanism Requirements

5.1 The communication mechanisms MUST NOT have any bearing on 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

   It should be possible to reference an incident report unambiguously
   using a globally unique identifier. 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 SHOULD support the description of various aspects of the
   source and target.

6.5 FINE SHOULD contain a description of the methodology used in
   the attacker.

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   Well-known classifications or enumeration schemes should be used to
   describe the attack or exploited vulnerabilities that caused the

6.6 FINE MUST include the identity of the creator of the incident

   FINE should indicate the source of each component of the incident
   report if is different from the creator (e.g., the team handling the

6.7 FINE SHOULD support the including or referencing information
   external to the incident report.

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 provide for describing the impact of the incident

6.11 FINE SHOULD support describing the actions taken during the
   course of handling an incident.

6.12 FINE SHOULD 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

   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 4.8).

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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.,
   "TERENA's Incident Object Description and Exchange Format
   Requirements", RFC 3067, February 2001

   [3] Meijer, J., Danyliw, R. 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 -

   [5]  Wood, M., "Intrusion Detection Exchange Format Requirements",
   work in progress (currently <draft-ietf-idwg-requirements-12.txt>).

   [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.

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   [11] Howard, J. and  Longstaff, A.,  "A Common Language for Computer
   Security Incidents", Sandia Report: SAND98-8667, Sandia National
   Laboratories, October 1998.

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

   The following individuals, in alphabetic order, have made substantial
   contribution to this document
         Hiroyuki Kido
         Kathleen M. Moriarty
         Roman Danyliw

11. Authors' Addresses:

   Yuri Demchenko
   University of Amsterdam, 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

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                        Full Copyright Statement

   Copyright (C) The Internet Society (2004).  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

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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 -03 (Second revision)
   1) title changed to
      Requirements for the Format for INcident information Exchange
   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
      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.

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   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.

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