Network Working Group Yuri Demchenko
INTERNET DRAFT University of Amsterdam
Category: Informational Hiroyuki Ohno
WIDE Project
Expires April 2004 Glenn M Keeni
Cyber Solutions Inc.
October, 2003
Requirements for Format for INcident information Exchange (FINE)
<draft-ietf-inch-requirements-02.txt>
Status of this Memo
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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 Incident related information across organizations, regions
and countries.
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INTERNET DRAFT FINE Requirements October, 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 ................................ 3
3. The Goal ................................................... 6
4. General Requirements ....................................... 6
5. Format Requirements ........................................ 6
6. Communication Requirements ................................. 7
7. Content Requirements ....................................... 7
8. Security Considerations .................................... 9
9. Acknowledgements ........................................... 9
10. References ................................................. 9
11. Authors' Addresses ......................................... 10
Full Copyright Statement ....................................... 11
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.
Definition of a common well defined format to Incident Reports will
facilitate incident related information exchange across organizations,
regions and countries by achieving these particular goals:
+ 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.
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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
For the purpose of clarify, 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. Attack
One or more steps taken by an attacker to achieve an unauthorised result.
An Attack can be active, passive. An attack may be successful.
2.1.2. Attacker
Attacker is an entity that attempts one or more attacks.
An attacker may be an insider, an outsider, or an entity acting via
an attack mediator. For the purpose of FINE, an attacker is described
by the computer/network ID, from which the attack was launched. The
organization 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 a free text description of the actual result of an
attack, and, where possible, structured information about the
particular damaged system, subsystem or service.
2.1.5. Event
An occurrence in a system or network, which maybe of interest and/or
warrants attention. An event may indicate an attack. An event may
also indicate an error or a fault or the result of a deliberate act
that is not an attack. For example, the occurrence of three failed
logins in 10 seconds is an event. It might indicate a brute- force
login attack. A program failure, network fault, system shutdown are
other examples of event.
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2.1.6. Impact
Impact describes the result of an 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 a set of one or more events. The events in the incident may
indicate attacks. There may be incidents which comprise of events
which are not indicative of attacks.
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, an Incident Report may have
some internal proprietary format that is adapted to the local
Incident Handling System (IHS) and Incident handling procedures.
Definition of the requirements to the format for Incident Report
exchange is the subject of this document.
2.1.9. Source
The source 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. 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.)
2.1.11. Victim
The entity which suffered the attack. For the purpose of FINE a
victim is described by its network ID, organization and location
information.
2.1.12. Other terms
Other terms used: alert, activity, IDS, Security Policy, etc., - are
defined in related I-Ds, RFCs, standards and documents[2, 3, 6, 7, 8,
9, 10].
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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
+-----
CSIRT |
+---------------------+ |
| | |
| +--------+ | |
| | | | |
| | | | Incident Report |
| |Incident|<---------|<----------------->| Customers/
| |ReportDB| | | CSIRTs/
| | | |<=== FINE ===>| Collaborators/
| | | | | Involved parties
| | | | |
| +--------+ | |
| | |
| | |
| | |
| | |
+---------------------+ +-----
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
states:
- handling the Incident Report 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;
+ the report is exchanged between CSIRTs and may be
investigated/processed by multiple CSIRTs, simultaneously;
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+ additions and/or changes to the report may be effected by one or
more CSIRTs. So a single CSIRT may not be in a position to vouch
for the veracity of all parts of the Incident Report,
3. The Goal. This section is eliminated but left as a placeholder until
final review
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 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.
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.
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5.4 FINE must support the application of an access restriction policy
to individual components 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.
5.5 FINE must support globally unique identifiers for the exchanged
Incident reports.
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. FINE must have a well defined semantics and provide a standard
way for extensibility in terms of addition of components and/or
extending the components.
5.7. FINE must allow multilingual reports. In case there are multiple
language versions of a component of the report, the versions should
be consistent and, and FINE must provide a way to identify which
version is authentic.
An 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.
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.
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
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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 of the Incident
Report (CSIRT or other authority). FINE should indicate the source of
each component of the Incident Report if its different from the
creator.
The source of a component of the Incident Report may be the creator
of the Incident Report, the team handling the incident or, some other
party.
7.6 FINE should provide the possibility to include or reference
additional detailed information/data external to report.
This information may include IDMEF [5] messages, which have been
generated by security devices.
7.7 FINE may contain a natural language description of the Incident
or related security events.
7.8 FINE should contain references to the appropriate advisories,
wherever applicable, corresponding to the related events , e.g.
CERT/CC, CVE, etc.
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.)
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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. time-stamped 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.
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 regarding access restriction policy as stated in 5.4 and
requirements regarding support of external mechanisms for
authenticity, integrity and non-repudiation 7.13.
9. 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 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
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[3] Incident Object Description and Exchange Format Data Model and
Extensible Markup Language (XML) Document Type Definition 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 - 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. 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 (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
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standards-related documentation can be found in BCP-11. Copies of
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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
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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 - non-normative
Major Changes (reverse count)
Information about changes to the document since publishing -00
version will be documented here.
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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