INCH Working Group Yuri Demchenko
Internet Draft University of Amsterdam
Category: Informational Hiroyuki Ohno
WIDE Project
Expires: November 6, 2005 Glenn M Keeni
Cyber Solutions Inc.
May 7, 2005
Requirements for the Format for INcident information Exchange (FINE)
<draft-ietf-inch-requirements-04.txt>
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Copyright (C) The Internet Society (2005). All Rights Reserved.
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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. 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",
"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 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
incident.
2.2 The Operational Model
Incident reports are an important subset of information exchanged
between a CSIRT and its constituency and other CSIRTs. A CSIRT may
create an incident report when information is reported to it. A CSIRT
may also receive incident reports from its constituency or from
another CSIRT. As analysis is performed and investigation occurs,
more information about an incident may be discovered causing updates
to previously sent incident reports to be exchanged.
Surrounding the creation and exchange of incident reports is often a
work-flow process to prioritize and manage the information flow in
the CSIRT. These systems often associate CSIRT analysts with
particular incidents or tag status onto a particular investigation.
FINE does not address these representation issues.
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FINE serves as the external representation for the data exchanged
between parties. Entities will have to make use of an interface to
convert between an internal data representation and FINE to convey
information to other parties as 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 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 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 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.
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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. FINE must support this
flexibility.
4.3 FINE MUST support aggregation and filtering of incident report data.
FINE must be defined with well-structured data elements and defined
semantics to support aggregation and filtering on these data elements
given a certain criteria.
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
incident report. 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.
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5. Communication Mechanism Requirements
5.1 The communication mechanisms MUST NOT solely be used to ensure the
security of a FINE-encoded 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. 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 by
the attacker.
Well-known classifications or enumeration schemes should be used to
describe the attack that caused the incident.
6.6 FINE MUST identify 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.
6.8 FINE MUST support natural language descriptions of the incident.
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6.9 FINE SHOULD support references to the appropriate advisories
from coordination and analysis centers.
6.10 FINE SHOULD provide means for describing the impact of the incident.
6.11 FINE SHOULD provide means for describing the actions taken during the
course of handling the 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
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.,
"TERENA's Incident Object Description and Exchange Format
Requirements", RFC 3067, February 2001
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[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
<draft-ietf-inch-iodef-03.txt>).
[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 <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.
[11] Howard, J. and Longstaff, A., "A Common Language for Computer
Security Incidents", Sandia Report: SAND98-8667, Sandia National
Laboratories, October 1998.
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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
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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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 -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
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.
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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.
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