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Versions: (draft-meijer-inch-iodef) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 RFC 5070

Network Working Group                                          J. Meijer
Internet-Draft                                                SURFnet bv
Expires: September 29, 2003                                   R. Danyliw
                                                CERT Coordination Center
                                                            Y. Demchenko
                                                              NLnet Labs
                                                          March 31, 2003


  The Incident Data Exchange Format Data Model and XML Implementation
                      draft-ietf-inch-iodef-01.txt

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 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/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on September 29, 2003.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   The purpose of the Incident Data Exchange Format (IODEF) is to define
   data formats for information related to computer security incidents
   typically exchanged between collaborating Computer Security Incident
   Response Teams (CSIRTs).  The IODEF satisfies the requirements
   specified in RFCXXX [1]

   This Internet-Draft describes a data model for representing commonly
   exchanged incident information exported from incident handling
   systems managed by CSIRTs.  An implementation of the data model in



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   the Extensible Markup Language (XML) is presented, an XML Document
   Type Definition is developed, and examples are provided.

Table of Contents

   1.     Introduction . . . . . . . . . . . . . . . . . . . . . . .   4
   1.1    Terminology  . . . . . . . . . . . . . . . . . . . . . . .   4
   1.2    Overview . . . . . . . . . . . . . . . . . . . . . . . . .   4
   1.3    About the IODEF Data Model . . . . . . . . . . . . . . . .   4
   1.3.1  Issues with Representing Incident Data . . . . . . . . . .   5
   1.4    About the IODEF Implementation . . . . . . . . . . . . . .   6
   1.5    Related Work . . . . . . . . . . . . . . . . . . . . . . .   6
   2.     Notational conventions and formatting issues . . . . . . .   8
   2.1    IODEF XML Documents  . . . . . . . . . . . . . . . . . . .   8
   2.1.1  The Document Prolog  . . . . . . . . . . . . . . . . . . .   8
   2.1.2  Character Data Processing in the IODEF . . . . . . . . . .   9
   2.1.3  Languages in the IODEF . . . . . . . . . . . . . . . . . .  10
   2.2    IODEF Data Types . . . . . . . . . . . . . . . . . . . . .  11
   2.2.1  Integers . . . . . . . . . . . . . . . . . . . . . . . . .  11
   2.2.2  Real Numbers . . . . . . . . . . . . . . . . . . . . . . .  11
   2.2.3  Characters and Strings . . . . . . . . . . . . . . . . . .  11
   2.2.4  Bytes  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   2.2.5  Enumerated Types . . . . . . . . . . . . . . . . . . . . .  12
   2.2.6  Date-Time Strings  . . . . . . . . . . . . . . . . . . . .  12
   2.2.7  NTP Timestamps . . . . . . . . . . . . . . . . . . . . . .  12
   2.2.8  Port Lists . . . . . . . . . . . . . . . . . . . . . . . .  12
   2.2.9  Postal Address . . . . . . . . . . . . . . . . . . . . . .  12
   2.2.10 Person or Organization . . . . . . . . . . . . . . . . . .  13
   2.2.11 Telephone and Fax Numbers  . . . . . . . . . . . . . . . .  13
   2.2.12 Email string . . . . . . . . . . . . . . . . . . . . . . .  13
   2.2.13 Uniform Resource Identifier strings  . . . . . . . . . . .  13
   2.2.14 Unique Identifiers . . . . . . . . . . . . . . . . . . . .  13
   3.     The IODEF Data Model . . . . . . . . . . . . . . . . . . .  14
   3.1    IODEF-Document . . . . . . . . . . . . . . . . . . . . . .  14
   3.2    Incident class . . . . . . . . . . . . . . . . . . . . . .  14
   3.3    IncidentID class . . . . . . . . . . . . . . . . . . . . .  16
   3.4    AlternativeID class  . . . . . . . . . . . . . . . . . . .  17
   3.5    RelatedActivity class  . . . . . . . . . . . . . . . . . .  18
   3.6    AdditionalData . . . . . . . . . . . . . . . . . . . . . .  19
   3.7    IncidentData . . . . . . . . . . . . . . . . . . . . . . .  20
   3.8    Contact class  . . . . . . . . . . . . . . . . . . . . . .  22
   3.8.1  RegistryHandle class . . . . . . . . . . . . . . . . . . .  25
   3.9    Time classes . . . . . . . . . . . . . . . . . . . . . . .  26
   3.9.1  StartTime  . . . . . . . . . . . . . . . . . . . . . . . .  26
   3.9.2  EndTime  . . . . . . . . . . . . . . . . . . . . . . . . .  26
   3.9.3  DetectTime . . . . . . . . . . . . . . . . . . . . . . . .  26
   3.9.4  ReportTime . . . . . . . . . . . . . . . . . . . . . . . .  27
   3.9.5  DateTime . . . . . . . . . . . . . . . . . . . . . . . . .  27



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   3.10   Expectation class  . . . . . . . . . . . . . . . . . . . .  27
   3.11   Method class . . . . . . . . . . . . . . . . . . . . . . .  28
   3.11.1 Classification class . . . . . . . . . . . . . . . . . . .  29
   3.12   Assessment class . . . . . . . . . . . . . . . . . . . . .  30
   3.12.1 Impact class . . . . . . . . . . . . . . . . . . . . . . .  31
   3.12.2 TimeImpact class . . . . . . . . . . . . . . . . . . . . .  33
   3.12.3 MonetaryImpact class . . . . . . . . . . . . . . . . . . .  34
   3.12.4 LifeImpact class . . . . . . . . . . . . . . . . . . . . .  35
   3.12.5 Confidence class . . . . . . . . . . . . . . . . . . . . .  36
   3.13   History class  . . . . . . . . . . . . . . . . . . . . . .  38
   3.13.1 HistoryItem class  . . . . . . . . . . . . . . . . . . . .  38
   3.14   EventData class  . . . . . . . . . . . . . . . . . . . . .  40
   3.15   Relating the IncidentData and EventData classes  . . . . .  42
   3.16   Cardinality of EventData . . . . . . . . . . . . . . . . .  43
   3.17   System class . . . . . . . . . . . . . . . . . . . . . . .  44
   3.18   Node class . . . . . . . . . . . . . . . . . . . . . . . .  46
   3.18.1 Address  . . . . . . . . . . . . . . . . . . . . . . . . .  48
   3.18.2 NodeRole class . . . . . . . . . . . . . . . . . . . . . .  48
   3.19   FileList class . . . . . . . . . . . . . . . . . . . . . .  50
   3.20   User . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
   3.21   Process  . . . . . . . . . . . . . . . . . . . . . . . . .  50
   3.22   Service  . . . . . . . . . . . . . . . . . . . . . . . . .  50
   3.23   Record class . . . . . . . . . . . . . . . . . . . . . . .  50
   3.23.1 RecordData class . . . . . . . . . . . . . . . . . . . . .  51
   4.     Extending the IODEF  . . . . . . . . . . . . . . . . . . .  55
   4.1    Extending the data model . . . . . . . . . . . . . . . . .  55
   4.2    Extending the XML DTD  . . . . . . . . . . . . . . . . . .  55
   5.     Processing Considerations  . . . . . . . . . . . . . . . .  58
   5.1    XML Validity and Well-Formedness . . . . . . . . . . . . .  58
   5.2    Unrecognized Data and XML Tags . . . . . . . . . . . . . .  58
   6.     Internationalization issues  . . . . . . . . . . . . . . .  60
   7.     Examples . . . . . . . . . . . . . . . . . . . . . . . . .  61
   7.1    Code Red detection notification  . . . . . . . . . . . . .  61
   7.2    IODEF-Document with XML signature  . . . . . . . . . . . .  63
   7.3    IODEF-Document encrypted using XML encryption  . . . . . .  63
   7.4    IODEF-Document encrypted and signed using XML signature
          & encryption . . . . . . . . . . . . . . . . . . . . . . .  63
   8.     The IODEF Document Type Definition . . . . . . . . . . . .  64
   9.     Security considerations  . . . . . . . . . . . . . . . . .  77
   10.    IANA considerations  . . . . . . . . . . . . . . . . . . .  78
   11.    Acknowledgments  . . . . . . . . . . . . . . . . . . . . .  79
          Normative References . . . . . . . . . . . . . . . . . . .  80
          Informative References . . . . . . . . . . . . . . . . . .  82
          Authors' Addresses . . . . . . . . . . . . . . . . . . . .  82
          Intellectual Property and Copyright Statements . . . . . .  83






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1. Introduction

1.1 Terminology

   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 RFC2119 [5].

   Definitions for some of the common computer security-related
   terminology used in this document can be found in Section 2 of [1].

1.2 Overview

   The Incident Data Exchange Format (IODEF) is intended to be a
   standard format for computer security information exchanged by
   Computer Security Incident Response Teams (CSIRTs).  The development
   and subsequent deployment of an incident data format that extends
   beyond a closed communities would improve the operational
   capabilities of the CSIRTs.

   Assuming widespread adoption of the IODEF by the community, an
   organization can potentially benefit from:

   o  the increased ease to collaborate with other CSIRTs, on behalf it
      its constituency, to resolve incidents;

   o  increased automation in the processing of incident data, since the
      commitment of security analysts to parse free-form textual
      document will be reduced;

   o  decreased effort in normalizing similar data (even when highly
      structured) from different sources; and

   o  a common format on which to build inter-operable tools for
      incident handling, such as correlation systems that process data
      from different sites.

   Terminology, notation, and conventions of the data model and XML DTD
   are presented in Sections 2.  The data model is described in Section
   3, and the implementation considerations are covered in Sections 4
   through 6, and 9.  Section 7 provides several examples of IODEF
   documents for representative incidents.  Section 8 formally specifies
   the XML DTD implementation of the data model.

1.3 About the IODEF Data Model

   The IODEF data model is an object-oriented representation of
   information reported, maintained, and exchanged by a CSIRT about a



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   computer security incident.

1.3.1 Issues with Representing Incident Data

   The IODEF data model addresses several problems in representing
   incident data:

   o  There is no precise, widely agreed upon definition for an
      incident.  Therefore, the data model does not attempt to imply a
      definition through its implementation.  Rather, a broad
      understanding is assumed that is flexible enough to encompass most
      of the CSIRT community.

   o  Incident data is inherently heterogeneous.  It may encompass many
      functional purposes  such as a description of intruder behavior or
      an analysis process correlating related incidents.
      An object-oriented model provides extensibility via aggregation
      and sub-classing while preserving the consistency of the model.
      If the data model required modification, it is extended with new
      classes.  In implementations that do not recognize these
      extensions, the basic subset of the data model will still be
      understood.

   o  Incidents have a life-cycle, which causes potentially different
      information or levels of detail to be present depending on their
      stage in the cycle.  For example, newly reported incidents may
      only contain a short description of the involved parties.  On the
      other hand, closed incidents can contain a full description
      complete with the associated evidence and annotation of actions
      taken by the CSIRT.  The data model that represents this
      information must be flexible to accommodate different needs.

   o  Communication and coordination are central to the role of a CSIRT.
      As a result of this activity, incident information can originate
      from a number of sources.  Tracking the all the sources of data is
      key to managing this information.
      The data model defines support classes that accommodate the
      differences between incident reporters. This support includes
      various meta information to represent the reporter's identity as
      well as prescribe a confidence level to the submitted information.

   o  Incident data may contain sensitive information. Such information
      should not be exposed to unauthorized parties during
      collaboration.
      The data model allows for a granular tagging in the individual
      classes to indication restrictions on the usage of the data.
      However, it is the role of the incident handling system
      implementing the data model to honor these labels.



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1.4 About the IODEF Implementation

   The IODEF implementation uses the Extensible Markup Language (XML)
   [2].  XML-based specifications define an XML DTD or Schema and
   register a specific XML namespace [3]. The IODEF conforms to the
   IETF-defined procedure for registering an application-specific XML
   namespace [9].

      For clarity in this document, we will use the terms "XML" and "XML
      documents" when speaking in the general case about the Extensible
      Markup Language (XML).  The terms "IODEF description", "IODEF
      markup" and "IODEF  document" will be used to refer to specific
      elements (tags) and attributes of the IODEF DTD.  Furthermore, the
      terms "class" and "subclass" are synonymous to an element in the
      XML DTD.

   The implementation of the IODEF in XML has many benefits:

   o  XML provides all the necessary features to define a specific
      markup language for describing security incidents. It also defines
      a standard way to extend this language, either for later revisions
      ("standard" extensions), or for organizational-specific use
      ("non-standard" extensions).

   o  Software tools for processing XML documents are widely available
      in commercial and open source forms.

   o  XML can aid in implementing internationalization and localization
      since it is required (and therefore IODEF documents are required)
      to support both the UTF-8 and UTF-16 encodings of ISO/IEC 10646
      (Universal Multiple-Octet Coded Character Set, "UCS") and Unicode.
      XML also provides support for specifying, on a per-element basis,
      the language in which the element's content is written, making the
      IODEF easy to adapt to the local languages in which a CSIRTs
      operates.

   o  XML coupled with XSL [4], a style language, allows IODEF documents
      to be aggregated, filtered, discarded, and rearranged.

   o  XML is free (no license, license fees or royalties).


1.5 Related Work

   The IODEF and the IDMEF [7] are complementary formats.  The latter
   represents data generated by an intrusion detection system.  Such
   event data is commonly used by a CSIRT as the basis for an incident
   report or investigation which is represented by the IODEF.



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   The IODEF data model makes use of certain classes defined in the
   IDMEF, although the semantics of some of these classes has changed.
   Due to their related nature, the data in an IDMEF message can be
   easily represented in an IODEF document.  Through various extension
   mechanisms, it is possible to include IDMEF messages outright in an
   IODEF document.  Alternatively, the similarity in structure of the
   data model makes it possible to decompose the key IDMEF data and
   include it in the corresponding IODEF classes.  However, this
   transformation may not preserve the original semantics of the data.










































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2. Notational conventions and formatting issues

2.1 IODEF XML Documents

   This document uses three notations: the Unified Modeling Language
   (UML) to describe the data model, an Extensible Markup Language (XML)
   Document Type Definition (DTD) to define the IODEF syntax, and IODEF
   XML markup conforming to the specified DTD to represent the incident
   data.

   This section describes the XML notations and conventions used in this
   memo and explains particular issues related to using them to describe
   the IODEF data model and syntax.  For readers unfamiliar with these
   notations [19] and [7] will provide a comprehensive reference.

2.1.1 The Document Prolog

   The "prolog" of an XML document, that part that precedes anything
   else, consists of the XML declaration and the document type
   declaration.

2.1.1.1 XML Declaration

   Every IODEF document starts with an XML declaration. The XML
   declaration specifies the version of XML being used, and optionally
   the character encoding being used (see Section 2.1.2).

   The XML declaration looks like:

   <?xml version="1.0" ?>

   IODEF documents exchanged between applications MUST begin with an XML
   declaration and MUST specify the XML version in use. Specification of
   the encoding in use is REQUIRED if UTF-8 encoding is not used.

2.1.1.2 IODEF DTD Formal Public Identifier

   The formal public identifier (FPI) for the IODEF Document Type
   Definition described in this document is:

        "-//IETF//DTD RFCxxxx IODEF v0.0//EN"

    NOTE: The "RFCxxxx" text in the FPI value will be replaced with the
   actual RFC number when this document is published as an RFC.

   This FPI MUST be used in the document type declaration within an XML
   document referencing the IODEF DTD defined by this document, as shown
   in Section 2.1.1.3.



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2.1.1.3 IODEF DTD Document Type Declaration

   The document type declaration for an XML document referencing the
   IODEF DTD will be specified in the following ways:

    <!DOCTYPE IODEF-Document PUBLIC "-//IETF//DTD RFCxxxx IODEF v0.0//EN">

    The last component of the document type declaration is the FPI
   specified in Section 2.1.1.2.

    <!DOCTYPE IODEF-Document SYSTEM "/path/to/IODEF-Document.dtd">

    The last component of the document type declaration is a URI that
   points to a copy of the Document Type Definition.

2.1.2 Character Data Processing in the IODEF

   A document's XML declaration specifies the character encoding to be
   used in the document, as follows:

   <?xml version="1.0" encoding="charset" ?>

   where "charset" is the name of the character encoding, as registered
   with the Internet Assigned Numbers Authority (IANA), see [9].

   The XML standard requires that XML processors support the UTF-8 and
   UTF-16 encodings of ISO/IEC 10646 (UCS) and Unicode, making all XML
   applications (and therefore, all IODEF-compliant applications)
   compatible with these common character encodings.

   While XML supports other character encodings (e.g., UTF-7, UTF-32),
   implementers should carefully consider the portability implications
   of using character encodings other than UTF-8 and UTF-16.

   Consistent with the XML standard, if no encoding is specified for an
   IODEF document, UTF-8 is assumed.  IODEF documents encoded in UTF-16
   MUST begin with the Byte Order Mark described by ISO/IEC 10646 Annex
   E and Unicode Appendix B (the "ZERO WIDTH NO-BREAK SPACE" character,
   #xFEFF).

2.1.2.1 Character Entity References

   Within XML documents, certain characters have special meanings in
   some contexts.  To include the actual character itself in one of
   these contexts, a special escape sequence, called an entity
   reference, must be used.

   The characters that sometimes need to be escaped, and their entity



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   references, are:

               Character        Entity Reference
               ---------------------------------
               &                 &amp;
               <                 &lt;
               >                 &gt;
               "                 &quot;
               '                 &apos;

                                Figure 1

   It is RECOMMENDED that IODEF-compliant applications use the entity
   reference form whenever writing these characters in data, to avoid
   any possibility of misinterpretation.

2.1.2.2 Character Code References

   Any character defined by the ISO/IEC 10646 and Unicode standards may
   be included in an XML document by the use of a character reference. A
   character reference is started with the characters '&' and '#', and
   ended with the character ';'.  Between these characters, the
   character code for the character inserted.

   If the character code is preceded by an 'x' it is interpreted in
   hexadecimal (base 16), otherwise, it is interpreted in decimal (base
   10).  For instance, the ampersand (&) is encoded as &#38; or &#x0026;
   and the less-than sign (<) is encoded as &#60; or &#x003C;.

   Any one-, two-, or four-byte character specified in the ISO/IEC 10646
   and Unicode standards can be included in a document using this
   technique.

2.1.2.3 White Space Processing

   All IODEF elements support the "xml:space" attribute. If "xml:space"
   is set to "preserve," the IODEF processing application MUST treat all
   white space in the element's content as significant.  If "xml:space"
   is "default," the application is free to do whatever it normally
   would with white space in the element's content.

2.1.3 Languages in the IODEF

   All IODEF tags support the "xml:lang" attribute thereby allowing each
   element to identify the language in which its content is.  The valid
   language code for the "xml:lang" attribute are described in RFC 3066
   [6].




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   IODEF messages SHOULD specify the language in which their contents
   are encoded. In general, the language can be specified with the
   "xml:lang" attribute in the top-level element and letting all other
   elements "inherit" that definition.

   If no language is specified in an IODEF document, English SHOULD be
   assumed.

2.2 IODEF Data Types

2.2.1 Integers

   Integer attributes are represented by the INTEGER data type. Integer
   data MUST be encoded in Base 10 or Base 16.

   Base 10 integer encoding uses the digits '0' through '9' and an
   optional sign ('+' or '-').  For example, "123", "-456".

   Base 16 integer encoding uses the digits '0' through '9' and 'a'
   through 'f' (or their upper case equivalents), and is preceded by the
   characters "0x".  For example, "0x1a2b".

2.2.2 Real Numbers

   Real (floating-point) attributes are represented by the REAL data
   type.  Real data MUST be encoded in Base 10.

   Real encoding is that of the POSIX "strtod" library function: an
   optional sign ('+' or '-') followed by a non-empty string of decimal
   digits, optionally containing a radix character, then an optional
   exponent part.  An exponent part consists of an 'e' or 'E', followed
   by an optional sign, followed by one or more decimal digits.  For
   example, "123.45e02", "-567,89e-03".

   IODEF-compliant applications MUST support both the '.' and ',' radix
   characters.

2.2.3 Characters and Strings

   Single-character attributes are represented by the CHARACTER data
   type.  Multi-character attributes of known length are represented by
   the STRING data type.

   Character and string data have no special formatting requirements,
   other than the need to occasionally use character references (see
   Section 2.1.2.1 and Section 2.1.2.2) to represent special characters.





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2.2.4 Bytes

   Binary data is represented by the BYTE (and BYTE[]) data type.

   Binary data MUST be encoded in its entirety using character code
   references (see ).

2.2.5 Enumerated Types

   Enumerated types are represented by the ENUM data type, and consist
   of an ordered list of acceptable values.  Each value has a
   representative keyword.  Within an IODEF document, the enumerated
   type keywords are used as attribute values

2.2.6 Date-Time Strings

   Date-time strings are represented by the DATETIME data type. Each
   date-time string identifies a particular instant in time; ranges are
   not supported.

   Date-time strings are formatted according to a subset of ISO
   8601:2000 [15] documented in RFC 3339 [14].

2.2.7 NTP Timestamps

   NTP timestamps are represented by the NTPSTAMP data type, and are
   described in detail in RFC 1305 [10] and RFC 2030 [11].  An NTP
   timestamp is a 64-bit unsigned fixed-point number.  The integer part
   is in the first 32 bits, and the fraction part is in the last 32
   bits.

   IODEF documents MUST encode NTP timestamps as two 32-bit hexadecimal
   values, separated by a period ('.'). For example,
   "0x12345678.0x87654321".

2.2.8 Port Lists

   A list of network ports are represented by the PORTLIST data type,
   and consist of a comma-separated list of numbers (individual
   integers) and ranges (N-M means ports N through M, inclusive). Any
   combination of numbers and ranges may be used in a single list. For
   example, "5-25,37,42,43,53,69-119,123-514".

2.2.9 Postal Address

   A postal address is represented by the POSTAL data type. The format
   of this address data is the documented in Sections 5.17 - 5.19 of RFC
   2256 [12].



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2.2.10 Person or Organization

   The name of an individual or organization is represented by the NAME
   data type. The format of the NAME data type is documented in Section
   5.4 of RFC 2256 [12].

2.2.11 Telephone and Fax Numbers

   A telephone number is represented by the PHONE data type. The format
   of the PHONE data type is documented in Section 5.21 of RFC 2256
   [12].

2.2.12 Email string

   An email address is represented by the EMAIL data type.  The format
   of the EMAIL data type is documented in Section 3.4.1 RFC 2822 [13]

2.2.13 Uniform Resource Identifier strings

   A uniform resource identifier (URI) is represented by the URI data
   type. The format of the URI data type is documented in RFC 2396 [8].

2.2.14 Unique Identifiers

   A unique identifier in the context of particular creator of IODEF
   documents (e.g., a CSIRT) is represented by the UID data type.  A
   globally unique identifier is represented by the GUID data type.  The
   UID and GUID data types are constructed from alphanumeric strings.























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3. The IODEF Data Model

   In this section, the individual components of the IODEF data model
   will be discussed in detail.  For each class, the semantics with be
   documented and the relationship between other classes with be
   presented with an UML diagram.

3.1 IODEF-Document

   The IODEF-Document class is the top level class in the IODEF data
   model and the DTD.  All IODEF documents are instances of the
   IODEF-Documents class.


   +-----------------+
   | IODEF-Document  |
   +-----------------+
   | STRING version  |<>--{1..*}--[ Incident ]
   |                 |
   +-----------------+

                     Figure 2: IODEF-Document class

   The aggregate class that constitutes IODEF-Document is:

   Incident
      One.  The Incident class contains all the incident-related
      information.

   The IODEF-Document class has one attribute:

   version
      Required.  STRING.  The version of the IODEF specification to
      which the IODEF document conforms.  The value of this attribute
      MUST be 1.0


3.2 Incident class

   Every incident reported to or handled by a CSIRT is represented by an
   instance of the Incident class. This class provides a standardized
   representation for commonly exchanged incident data and associates a
   unique identifier with the described activity.








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   +-------------------+
   | Incident          |
   +-------------------+
   | ENUM purpose      |<>----------[ IncidentID      ]
   | ENUM restriction  |
   |                   |<>--{0..1}--[ AlternativeIDs  ]
   |                   |
   |                   |<>----------[ IncidentData    ]
   |                   |
   |                   |<>--{0..1}--[ RelatedActivity ]
   |                   |
   |                   |<>--{0..*}--[ AdditionalData  ]
   +-------------------+

                      Figure 3: the Incident class

   The aggregate classes that constitute Incident are:

   IncidentID
      One.  The incident tracking number or unique identifier assigned
      to this incident by the party that generated the document.

   AlternativeIDs
      Zero or one.  A list of incident tracking numbers used by other
      CSIRTs to refer to same activity as described in the document.

   RelatedActivity
      Zero or one.  A list of incident tracking numbers referencing
      related incidents.

   IncidentData
      Zero or more.  The event(s) that constitute the incident about
      which the IODEF-Document conveys information.

   AdditionalData
      Zero or more.  Extension area for data that cannot be represented
      anywhere else.

   The Incident class has two attributes:

   purpose
      Required.  ENUM.  The purpose of the IODEF document.  This
      attribute is defined as an enumerated list:

      1.  handling. The IODEF-Document was sent for incident-handling
          purposes;

      2.  statistics. The IODEF-Document was sent to be included in a



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          data-repository for statistical purposes;

      3.  warning. The IODEF-Document was sent as a warning;

      4.  other. The IODEF-Document was sent for purposes specified in
          the AdditionalData element.

   restriction
      Optional.  ENUM.  This attribute indicates the disclosure
      guidelines to which the sender expects the recipient of the
      IODEF-Document to adhere. However, it is the choice of the
      recipient of the document to honor this guideline.

      The value of this attribute is logically inherited by the children
      of this class.  That is to say, the disclosure rules applied to
      this class, also apply to its children.

      It is possible to set a granular disclosure policy, since many of
      the high-level classes have a restriction attribute.  Therefore, a
      child can override the guidelines of a parent class, be it to
      tighten or relax the disclosure rules (i.e., a child has a weaker
      policy than an ancestor; or an ancestor has a weak policy, and the
      children selectively apply more rigid controls).  The implicit
      value of the restriction attribute for a class that did not
      specify one can be found in the closest ancestor that did specify
      a value.

      This attribute is defined as an enumerated value with a default
      value of "private".

      1.  public.  There is no restriction level applied to the
          information;

      2.  need-to-know.  The information may be shared with other
          parties that are involved in the incident (e.g., multiple
          victim sites can be informed of each other);

      3.  private.  The information may not be shared.

      4.  default.  The information can be shared according to an
          information disclosure policy pre-arranged by the
          communicating parties.



3.3 IncidentID class

   The IncidentID class represents the incident tracking number or



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   identifier used by a CSIRT or reporter to uniquely identify (in their
   organization) the activity characterized in this IODEF-Document.

   +------------------+
   | IncidentID       |
   +------------------+
   | UID              |
   |                  |
   | GUID   name      |
   +------------------+

                     Figure 4: the IncidentID class

   The element content represents an incident tracking number (UID) that
   is unique in the context of the CSIRT.

   The IncidentID class has one attribute:

   name
      Required.  GUID.  An identifier for the CSIRT that created the
      IODEF-Document.


3.4 AlternativeID class

   The AlternativeID class references the incident tracking numbers or
   unique identifiers used by other entities (e.g., CSIRTs) to refer to
   activity identical to that characterized in this IODEF-Document.
   Thus, tracking numbers listed as an AlternativeID are the same events
   detected by another CSIRT, but seem from a different perspective.  It
   follows, the incident tracking numbers of the organization that
   generated the IODEF-Document should never be considered an
   AlternativeID.

   If the incident is not the identical activity, but is related (e.g.,
   same methodology or intruder), then its incident tracking number
   should instead be represented in the RelatedActivity (Section 3.5)
   class.













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         +------------------+
         | AlternativeID    |
         +------------------+
         | ENUM restriction |<>--{1..*}--[ IncidentID ]
         |                  |
         +------------------+


                   Figure 5: the AlternativeID class

   The aggregate classes that constitute AlternativeID are:

   IncidentID
      One or more.  Unique identifiers assigned by another entity for
      the identical activity characterized in the IODEF-Document.

   The AlternativeID class has one attribute:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.


3.5 RelatedActivity class

   The RelatedActivity class references the incident tracking numbers or
   unique identifiers of incidents that are related to the one described
   in the IODEF document.  These references may to local incident
   tracking numbers, as well as, to those of other CSIRTs.

   The specifics of how a CSIRT came to believe that two incidents are
   related is considered out of scope.


         +------------------+
         | RelatedActivity  |
         +------------------+
         | ENUM restriction |<>--{1..*}--[ IncidentID ]
         |                  |
         +------------------+

                    Figure 6: RelatedActivity class

   The aggregate classes that constitute RelatedActivity are:

   IncidentID
      One or more.  Unique identifiers assigned by the CSIRT.

   The RelatedActivity class has one attribute:



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   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.


3.6 AdditionalData

   The AdditionalData class serves as an extension mechanism for
   information not otherwise represented in the data model. For
   relatively simple information, atomic data (integers, strings, etc.)
   types are provided with a mechanism to annotate their meaning.  The
   class can also be used to extend the data model and the DTD to
   support proprietary extensions by encapsulating entire XML documents
   conforming to another DTD (e.g., IDMEF).  A detailed discussion for
   extending the data model and the DTD can be found in Section 4.

   Unlike XML, which is self-describing, atomic data must typically be
   documented to convey its meaning.  This information is described in
   the 'meaning' attribute.  Since these description are outside the
   scope of the specification, some additional coordination may be
   required to ensure that a recipient of a document using the
   AdditionalData classes can make sense of the custom extensions.


   +------------------+
   | AdditionalData   |
   +------------------+
   | ANY              |
   |                  |
   | ENUM restriction |
   | ENUM type        |
   | STRING meaning   |
   +------------------+

                   Figure 7: the AdditionalData class

   The AdditionalData class has three attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   type
      Required.  ENUM.  The data type of the element content. The
      permitted values for this attribute are shown below. The default
      value is "string".

      1.   boolean.  The element contains a boolean value, i.e., the
           strings "true" or "false"




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      2.   byte.  The element content is a single 8-bit byte (see
           Section 2.2.4);

      3.   character.  The element content is a single character (see
           Section 2.2.3);

      4.   date-time.  The element content is a date-time string (see
           Section 2.2.6);

      5.   integer.  The element content is an integer (see Section
           2.2.1);

      6.   ntpstamp.  The element content is a NTP timestamp (see
           Section 2.2.7);

      7.   portlist.  The element content is a port list (see Section
           2.2.8);

      8.   real.  The element content is a real number (see xref
           target="dt_real_numbers" />);

      9.   string.  The element content is a string (see Section 2.2.3);

      10.  xml.  The element content is XML-tagged data (see Section 4).

   meaning
      Optional.  STRING.  A description of the semantics of the custom
      data in this class.


3.7 IncidentData

   The IncidentData class summarizes the details of the incident
   activity and a CSIRT's handling of the information, as well as,
   groups the security events that constitute the incident.

   Many of the aggregated classes of IncidentData are also found in
   EventData, albeit with different occurrence indicators.  However, the
   semantics of these classes is quite different.  The classes of
   IncidentData reflect information relevant across the entire incident,
   while the classes of EventData provide information only relevant to
   the given event or system node being described.  The relationship
   between the IncidentData and EventData classes is complementary. The
   latter provides summary information, while the former provides more
   specific details.  For example, the overall impact of the incident
   (represented in IncidentData) might be denial of service, but it
   might be worth mentioning that there were specific machines
   (represented in EventData) which also suffered a root compromise. In



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   another example, an organizational contact can be provided in
   IncidentData class, while more specific contacts for the individual
   hosts can be in the EventData class.

   IncidentData also ensures that certain mandatory information will be
   present in the data model.


   +------------------+
   | IncidentData     |
   +------------------+
   | ENUM restriction |<>--{0..*}--[ Description    ]
   |                  |
   |                  |<>--{1..*}--[ Assessment     ]
   |                  |
   |                  |<>--{0..*}--[ Method         ]
   |                  |
   |                  |<>--{0..1}--[ DetectTime     ]
   |                  |
   |                  |<>--{0..1}--[ StartTime      ]
   |                  |
   |                  |<>--{0..1}--[ EndTime        ]
   |                  |
   |                  |<>----------[ ReportTime     ]
   |                  |
   |                  |<>--{1..*}--[ Contact        ]
   |                  |
   |                  |<>--{0..*}--[ Expectation    ]
   |                  |
   |                  |<>--{0..1}--[ History        ]
   |                  |
   |                  |<>--{0..*}--[ EventData      ]
   |                  |
   |                  |<>--{0..*}--[ AdditionalData ]
   +------------------+

                    Figure 8: the IncidentData class

   The aggregate classes that constitute IncidentData are:

   Description
      Zero or more.  STRING.  A free-form textual description of the
      incident activity

   Assessment
      One or more.  A characterization of the impact the incident
      activity.




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   Method
      Zero or more.  The techniques (e.g., tools, vulnerabilities) used
      by the intruder.

   DetectTime
      Zero or one.  The time the incident activity was first detected.

   StartTime
      Zero or one.  The time the incident activity started.

   EndTime
      Zero or one.  The time the incident activity ended.

   ReportTime
      One.  The time the incident activity was reported.

   Contact
      One or more.  Contact information for the parties involved in the
      incident.

   Expectation
      Zero or more.  Expected action to be performed by the recipient of
      the document.

   History
      Zero or one.  Documents significant events or actions that
      occurred during the course of handling the incident.

   EventData
      Zero or more.  Details on the Data on the (security) events that
      lead to the incident.

   AdditionalData
      Zero or more.  An area to extend the data model with information
      that can not be represented elsewhere.

   The IncidentData class has one attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.


3.8 Contact class

   The Contact class describes contact information for organizations and
   personnel involved in the incident.  This class encapsulates naming
   the involved party, specifying contact information to reach them, and
   identifying their role in the incident.



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   People and organizations are treated interchangeably as contacts; one
   can be associated with the other using the recursive definition of
   the class. The 'type' attribute determines the type of contact
   information being provided.

   The recursive definition of this class (the Contact class is
   aggregated into the Contact class) provides a way to relate
   information without requiring the explicit use of identifiers in the
   classes.  When grouping people into organizations it is RECOMMENDED
   to nest the persons instances into an organization instance of this
   class.


   +------------------+
   | Contact          |
   +------------------+
   | ENUM restriction |<>--{0..1}--[ name           ]
   | ENUM role        |
   | ENUM type        |<>--{0..*}--[ Description    ]
   |                  |
   |                  |<>--{0..*}--[ RegistryHandle ]
   |                  |
   |                  |<>--{0..1}--[ PostalAddress  ]
   |                  |
   |                  |<>--{0..*}--[ Email          ]
   |                  |
   |                  |<>--{0..*}--[ Telephone      ]
   |                  |
   |                  |<>--{0..1}--[ Fax            ]
   |                  |
   |                  |<>--{0..1}--[ Timezone       ]
   |                  |
   |                  |<>--{0..*}--[ Contact        ]
   +------------------+

                      Figure 9: the Contact class

   The aggregate classes that constitute the Contact class are:

   name
      Zero or one.  NAME.  The name of the contact.  The contact may
      either be an organization or a person.  The type attribute
      dictates the semantics (organization or person).

   Description
      Zero or one.  STRING.  Free-form description of the this contact.
      In the case of a person, this is often the organizational title of
      the individual.



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   RegistryHandle
      Zero or many.  The handle name in a registry.  Care must be taken
      to ensure that a handle is meaningful to the recipient.
      Intra-organizational handles are of not much use for
      extra-organizational communication.

   PostalAddress
      Zero or one.  POSTAL.  The postal address of the contact formatted
      according to Section 2.2.9.

   Email
      Zero or many.  EMAIL.  The email address of the contact formatted
      according to Section 2.2.12.

   Telephone
      Zero or many.  PHONE.  The telephone number of the contact
      formatted according to .

   Fax
      Zero or one.  PHONE.  The facsimile telephone number of the
      contact formatted according to .

   Timezone
      Zero or one.  STRING. The timezone in which the contact resides.

   Contact
      Zero or many.  Recursive definition of Contact, allowing for
      grouping of data.  An example of this is an organization with
      multiple contact persons.

   The Contact class has three attributes:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.

   role
      Required.  ENUM.  Indicates the role the Contact fulfills.   This
      attribute is defined as an enumerated list:

      1.  creator.  The entity that generate the IODEF document.

      2.  admin.  An administrative contact for a host or network.

      3.  tech.  A technical contact for a host or network.

      4.  irt.  The CSIRT involved in handling the incident.

      5.  cc.  An entity that is to be kept informed about the the



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          handling of the incident.

   type
      Required.  ENUM.  Indicates the type of Contact being provided.
      This attribute is defined as an enumerated list:

      1.  person.

      2.  organization.


3.8.1 RegistryHandle class

   The RegistryHandle class represents a handle to an Internet registry
   or community-specific database.  A handle consists of a name
   specified in the element content, and the database to which it
   belongs specified in the type attribute.


   +------------------+
   | RegistryHandle   |
   +------------------+
   | STRING           |
   |                  |
   | ENUM type        |
   +------------------+

                  Figure 10: The RegistryHandle class

   The RegistryHandle class has one attribute:

   type
      Required.  ENUM.  The database to which the handle belongs.   The
      default value is 'local'.  The possible values are:

      1.  internic.  Internet Network Information Center

      2.  apnic.  Asia Pacific Network Information Center

      3.  arin.  American Registry for Internet Numbers

      4.  lacnic.  Regional Latin-American and Caribbean IP Address
          Registry

      5.  ripe.  Reseaux IP Europeens

      6.  ti.  TERNEA Trusted Introducer




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      7.  local.  A database local to the CSIRT.


3.9 Time classes

   The data model uses for different classes to represent a timestamp.
   Their definition is identical, but each is named differently to
   convey a semantic difference.

   The element content of each class is a timestamp formated according
   to the DATETIME data type (see Section 2.2.6).


   +----------------------------------+
   | {Start| End| Report| Detect}Time |
   +----------------------------------+
   | DATETIME                         |
   |                                  |
   | NTPSTAMP ntpstamp                |
   +----------------------------------+

                      Figure 11: the Time classes

   The Time classes have one attribute:

   ntpstamp
      Optional.  NTPTIMESTAMP.  The NTP timestamp representing the
      timestamp in the element content.  The NTPSTAMP format of this
      attribute's value is described in Section 2.2.7.

   The use of the ntpstamp attribute is optional since it is redundant.
   However, it has been maintained to ensure compatibility with the
   IDMEF [7].  Representing a timestamp in both the element content and
   attribute is NOT RECOMMENDED.  However, if both are used, their
   values MUST be identical.

3.9.1 StartTime

   The StartTime class represents timestamp for the start of an
   activity.

3.9.2 EndTime

   The EndTime class represents the timestamp for the end of an
   activity.

3.9.3 DetectTime




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   The DetectTime class represents the timestamp of when an activity was
   first detected.

3.9.4 ReportTime

   The ReportTime class represents the timestamp of when a detected
   activity was reported.

3.9.5 DateTime

   The DateTime class is a generic representation of a timestamp.  Its
   semantics should be inferred from the parent class into which it is
   aggregated.

3.10 Expectation class

   The Expectation class conveys to the recipient of the IODEF document
   the actions the sender is requesting.

   +------------------+
   | Expectation      |
   +------------------+
   | ENUM restriction |<>--{1..*}--[ Description ]
   | ENUM priority    |
   | ENUM category    |<>--{0..1}--[ StartTime   ]
   |                  |
   |                  |<>--{0..1}--[ EndTime     ]
   |                  |
   |                  |<>--{0..1}--[ Contact     ]
   +------------------+

                    Figure 12: the Expectation class

   The aggregate classes that constitute Expectation are:

   Description
      One or many.  STRING.  A free-form description of the desired
      action(s).

   StartTime
      Zero or one.  The time at which the action should be performed.  A
      timestamp that is earlier than the ReportTime specified in the
      IncidentData class denotes that the expectation should be
      fulfilled as soon as possible.  The absence of this element leaves
      the execution of the expectation to the discretion of the
      recipient.





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   EndTime
      Zero or one.  The time by which the action should be completed.
      If the action is not carried out by this time, it should no longer
      be performed.

   Contact
      Zero or one.  The expected actor for the action.  The 'role'
      attribute of the Contact MUST be set to "actor".

   The Expectations class has three attributes:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.

   priority
      Optional.  ENUM.  Indicates the desired priority of the action.
      This attribute is an enumerated list with no default value.

      1.  low.  Low priority

      2.  medium. Medium priority

      3.  high. High priority

   category
      Optional.  ENUM.  Classifies the type of action requested.  This
      attribute is an enumerated list with no default value.

      1.  nothing.  No action is requested.  Do nothing with the
          information.

      2.  contact-site.  Contact the listed site in the recipient's
          constituency.

      3.  contact-me.  Contact the originator of the document.

      4.  block.  Block or investigate machines listed in the document
          in the recipient's constituency.


3.11 Method class

   The Method class provides information about the methodology used by
   the intruder to perpetrate the events of the incident.  This class
   can reference well-known vulnerability or exploit databases, list the
   intruder tools used in the attack, and provide for a free-form
   description of the activity.




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   +------------------+
   | Method           |
   +------------------+
   | ENUM restriction |<>--{0..*}--[ Classification ]
   |                  |
   |                  |<>--{0..*}--[ Description    ]
   +------------------+

                      Figure 13: The Method class

   The Method class is composed of two aggregate classes.

   Classification
      Zero or many.  A reference to a well-known vulnerability or
      exploit databases.

   Description
      Zero or many.  STRING A free-form text description of the
      methodology used in the incident.

   The Method class has one attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.


3.11.1 Classification class

   The Classification class is a reference to an external database of
   computer vulnerabilities, exposures, or viruses.  A reference
   consists of the database name, the entry in the database, and the URI
   to this entry.

   +------------------+
   | Classification   |
   +------------------+
   | ENUM restriction |<>----------[ name ]
   | ENUM origin      |
   |                  |<>----------[ url  ]
   +------------------+

                  Figure 14: The Classification class

   The aggregate classes that constitute Classification:

   name
      One.  STRING.  The name of the reference to the database specified
      in the origin attribute.



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   url
      One.  URI.  A URL to additional information about the
      vulnerability or exposure referenced by the name.

   The Classification class has two attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.

   origin
      Required.  ENUM.  The name of the database to which the reference
      is being made.  The permitted values are shown below.

      1.  bugtraqid.  Bugtraq

      2.  cve.  Common Vulnerabilities or Exposures

      3.  certcc.  CERT Coordination Center Vulnerability Catalog

      4.  vendor.  A product vendor whose name should be specified in
          the name class

      5.  local.  A local database.

      6.  other.


3.12 Assessment class

   The Assessment class describes the technical and non-technical
   repercussions of the incident activity.

   Note: The IODEF definition of the Assessment class reuses the IDMEF
   definition (see Section 4.2.4.5 of [7]), but also extends it.

















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         +------------------+
         | Assessment       |
         +------------------+
         | ENUM restriction |<>--{0..*}--[ Impact         ]
         |                  |
         |                  |<>--{0..*}--[ TimeImpact     ]
         |                  |
         |                  |<>--{0..*}--[ MonetaryImpact ]
         |                  |
         |                  |<>--{0..*}--[ LifeImpact     ]
         |                  |
         |                  |<>--{0..1}--[ Confidence     ]
         +------------------+

                      Figure 15: Assessment class

   The aggregate classes that constitute Assessment are:

   Impact
      Zero or many.  Technical impact of the activity on the computers
      and networks.

   TimeImpact
      Zero or many.  Impact of the activity measured with respect to
      time.

   MonetaryImpact
      Zero or many.  Impact of the activity measured with respect to
      money.

   LifeImpact
      Zero or many.  Impact of the activity measured with respect to
      human life.

   Confidence
      Zero or one.  An estimate of confidence in the assessment.

   The Assessment class has one attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.


3.12.1 Impact class

   The Impact class allows for classifying as well as providing a
   description of the technical impact due to the incident activity on
   the computers and networks of an organization.



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   Attributes allow the impact to be classified according to the
   consequences on the host and the severity of these consequences. The
   element content is used for the description.

   Note: The IODEF definition of the Impact class reuses the IDMEF
   definition (see Section 4.2.6.1 of [7]), but also extends it and
   alters the semantics.

   +------------------+
   | Impact           |
   +------------------+
   | STRING           |
   |                  |
   | ENUM restriction |
   | ENUM severity    |
   | ENUM completion  |
   | ENUM type        |
   +------------------+

                        Figure 16: Impact class

   The element content may be empty, or contain a free-form description
   (STRING) of the technical impact.

   The Impact class has four attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   severity
      Optional.  ENUM.  An estimate of the relative severity of the
      activity. The permitted values are shown below.  There is no
      default value.

      1.  low.  Low severity

      2.  medium. Medium severity

      3.  high. High severity

   completion
      Optional.  ENUM.  An indication of whether the creator of the
      IODEF document believes the activity was successful.  The
      permitted values are shown below. There is no default value.

      1.  failed.  The attempt was not successful

      2.  succeeded.  The attempt succeeded



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   type
      Required.  ENUM.  The type of impact in relatively broad
      categories.  The permitted values are shown below.  The default
      value is "unknown."

      1.  admin.  Administrative privileges were attempted or obtained

      2.  dos.  A denial of service was attempted or completed

      3.  file.  An action on a file was attempted or completed

      4.  recon.  A reconnaissance probe was attempted or completed

      5.  user.  User privileges were attempted or obtained

      6.  none.  The activity did not have any (technical) impact

      7.  unknown.  The impact of the activity is unknown

      8.  other.  Anything not in one of the above categories


3.12.2 TimeImpact class

   The TimeImpact class describes the non-technical impact of the
   activity on an organization as a function of time. Different types of
   time calculations and well as units can be used.


         +------------------+
         | TimeImpact       |
         +------------------+
         | REAL             |
         |                  |
         | ENUM restriction |
         | ENUM severity    |
         | ENUM metric      |
         | ENUM units       |
         +------------------+

                      Figure 17: TimeImpact class

   The element content will be a numeric value (REAL) specifying the
   impact as a function of time.  The attributes represent the specific
   units and metric.

   The TimeImpact class has four attributes:




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   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   severity
      Optional.  ENUM.  An estimate of the relative severity of the
      activity. The permitted values are shown below.  There is no
      default value.

      1.  low.  Low severity

      2.  medium. Medium severity

      3.  high. High severity

   metric
      Required.  ENUM.  Defines the metric in which the time is
      expressed.  The permitted values are shown below.  There is no
      default value.

      1.  labor.  Total staff-time to recovery from the activity (e.g.,
          2 employees working 4 hours each would be 8 hours)

      2.  elapsed.  Elapsed time from the beginning of the recovery to
          its completion.

      3.  downtime.  Duration of time for which some provided service(s)
          was not available.

   units
      Required.  ENUM.  Defines the units in which the metric is
      expressed.  The permitted values are shown below. The default
      value is "hours".

      1.  seconds.  Seconds

      2.  minutes.  Minutes

      3.  hours. Hours

      4.  days.  Days


3.12.3 MonetaryImpact class

   The MonetaryImpact class describes the financial impact of the
   activity on an organization.  For example, this impact may consider
   loss due to the cost of the investigation or recovery, diminished
   productivity of the staff, or a tarnished reputation that will affect



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   future opportunities.


         +------------------+
         | MonetaryImpact   |
         +------------------+
         | REAL             |
         |                  |
         | ENUM restriction |
         | ENUM severity    |
         | ENUM metric      |
         | STRING currency  |
         +------------------+

                    Figure 18: MonetaryImpact class

   The element content will be a numeric value (REAL) specifying the
   impact as a function of money.  The attributes represent the specific
   currency and metric.

   The MonetaryImpact class has four attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   severity
      Optional.  ENUM.  An estimate of the relative severity of the
      activity. The permitted values are shown below.  There is no
      default value.

      1.  low.  Low severity

      2.  medium. Medium severity

      3.  high. High severity

   currency
      Required.  ENUM.  Defines the currency in which the monetary
      impact is expressed.      The permitted values are defined in ISO
      4217:2001, Codes for the representation  of currencies and funds
      [18].  There is no default value.


3.12.4 LifeImpact class

   The LifeImpact class describes the loss of human life or injury due
   to an incident.




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         +------------------+
         | LifeImpact       |
         +------------------+
         | INTEGER          |
         |                  |
         | ENUM restriction |
         | ENUM severity    |
         | ENUM metric      |
         +------------------+

                      Figure 19: LifeImpact class

   The element content will be a numeric value (INTEGER) specifying the
   impact as a function of human life.  The attributes represent the
   specific metric.

   The LifeImpact class has three attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   severity
      Optional.  ENUM.  An estimate of the relative severity of the
      activity. The permitted values are shown below.  There is no
      default value.

      1.  low.  Low severity

      2.  medium. Medium severity

      3.  high. High severity

   metric
      Required.  ENUM.  Defines the metric in which the LifeImpact is
      expressed.  The permitted values are shown below.  There is no
      default value.

      1.  Deaths

      2.  Injuries


3.12.5 Confidence class

   The Confidence class represents a best estimate of the validity and
   accuracy of the described impact (see Section 3.12) of the incident
   activity. This estimate can be expressed as a category, or a numeric
   calculation.



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   Note: The IODEF definition of the Confidence class reuses the IDMEF
   definition (see Section 4.2.6.3 of [7]), but also extends it and
   alters the semantics.

   The Confidence class has been reused from the IDMEF [7], it has been
   extended and has been altered.


         +------------------+
         | Confidence       |
         +------------------+
         | REAL             |
         |                  |
         | ENUM restriction |
         | ENUM rating      |
         +------------------+

                      Figure 20: Confidence class

   The element content may be empty if the rating attribute is not set
   to "numeric".  Otherwise, a confidence value (REAL) must be provided.

   The Confidence class has two attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   rating
      Required.  ENUM.  Indicates the confidence the CSIRT has in its
      assessment. The permitted values are shown below.  The default
      value is "numeric."

      1.  low

      2.  medium

      3.  high

      4.  numeric.  The CSIRT has provided a probability value
          indicating its confidence in its assessment.

      5.  unknown

   This element SHOULD only be used when the CSIRT can produce
   meaningful information.  When only a rough estimate is possible
   "low", "medium", or "high" SHOULD be used as the rating value.

   When a reasonable probability estimate is possible "numeric" SHOULD



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   be used as the rating value and include a numeric confidence value in
   the element content. This numeric value is a floating point number
   between 0.0 and 1.0, inclusive.

   Different CSIRTs may compute and represent confidence values in
   different ways.  Care should be taken to take proper notice of the
   exact meaning of the confidence values of different CSIRTs when
   comparing confidence values.

3.13 History class

   The History class is a log or diary of the significant events that
   occurred or actions performed by the involved parties (e.g., initial
   reporter, investigating CSIRT, or involved system administrators)
   during the course of handling the incident.

   The level of detail maintained in this log is left up to the
   discretion of those handling the incident.


   +------------------+
   | History          |
   +------------------+
   | ENUM restriction |<>--{1..*}--[ HistoryItem ]
   |                  |
   +------------------+

                      Figure 21: The History class

   The class that constitute History are:

   HistoryItem
      One or many.  Entries in the history log of significant events or
      actions performed by the involved parties.

   The History class has one attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.


3.13.1 HistoryItem class

   The HistoryItem class is a particular entry in the History (Section
   3.13) log that documents a particular significant action or event
   that occurred in the course of handling the current incident.  This
   details of the entry in this log are a free-form description, but
   each can also be categorized.



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   +------------------+
   | HistoryItem      |
   +------------------+
   | ENUM restriction |<>--{0..1}--[ IncidentID  ]
   | ENUM type        |
   |                  |<>----------[ DateTime    ]
   |                  |
   |                  |<>--{1..*}--[ Description ]
   +------------------+

                      Figure 22: HistoryItem class

   The aggregate classes that constitute HistoryItem are:

   IncidentID
      Zero or One.  In history logs created by multiple parties, the
      IncidentID provides a way specify which CSIRT created the
      particular entry and reference this organizations local incident
      tracking number for this activity.  When a single organization is
      maintaining the history log, this class can be ignored.

   DateTime
      One.  Timestamp of the this entry in the history log (e.g., when
      the action described in the Description was taken).

   Description
      One or many.  STRING.  A free-form textual description of the
      action or event to be document in the history log.

   The HistoryItem class has two attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.

   type
      Optional.  ENUM.  Classifies the type of activity or event being
      document in this history log entry.  The particular details of the
      entry are a free-form description documented in the Description
      class.  Possible values are an enumerated list whose default value
      is "other":

      1.  triaged.  The incident data was received and processed by an
          IHS

      2.  notification.  Notification to an involved party in the
          incident was sent (e.g., a CSIRT sending a message to the
          attacking site).




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      3.  shared-info.  Information about this incident was shared with
          party not directly involved.

      4.  received-info.  Additional information about the incident was
          received

      5.  remediation. The incident has been resolved; a short
          description may be included.

      6.  other.


3.14 EventData class

   The EventData class describes the events of the incident surrounding
   a particular set of hosts or networks.  This description includes the
   systems from which the activity originated and those targeted, an
   assessment of the techniques used by the intruder, the impact of the
   activity on the organization, a list of incident handling tasks
   performed, and and any forensic evidence discovered.































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   +------------------+
   | EventData        |
   +------------------+
   | ENUM restriction |<>--{0..*}--[ Description    ]
   |                  |
   |                  |<>--{0..1}--[ Assessment     ]
   |                  |
   |                  |<>--{0..*}--[ Method         ]
   |                  |
   |                  |<>--{0..1}--[ DetectTime     ]
   |                  |
   |                  |<>--{0..1}--[ StartTime      ]
   |                  |
   |                  |<>--{0..1}--[ EndTime        ]
   |                  |
   |                  |<>--{0..*}--[ Contact        ]
   |                  |
   |                  |<>--{0..1}--[ History        ]
   |                  |
   |                  |<>--{0..*}--[ System         ]
   |                  |
   |                  |<>--{0..1}--[ Record         ]
   |                  |
   |                  |<>--{0..*}--[ EventData      ]
   |                  |
   |                  |<>--{0..*}--[ AdditionalData ]
   +------------------+

                     Figure 23: The EventData class

   The aggregate classes that constitute EventData are:

   Description
      Zero or more.  STRING.  A free-form textual description of the
      event.

   System
      Zero or more.  The systems (nodes, networks) involved in the event
      as either sources, targets or intermediaries.

   Method
      Zero or more.  The methods by which the event was staged.
      Information about tools used and vulnerabilities exploited.

   Record
      Zero or one.  Support data (e.g., log files) that provides
      information on the events.




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   StartTime
      Zero or one.  The time the event started.

   EndTime
      Zero or one.  The time the event ended.

   DetectTime
      Zero or one.  The time the event was detected.

   Contact
      Zero or more.  The different parties involved in the incident

   Assessment
      Zero or one.  Indicates the impact of the incident on the target
      and the actions taken.

   AdditionalData
      Zero or one.  Anything that can not be put in one of the other
      elements

   Event
      Zero or more.  Recursive definition of Event, allowing for
      grouping of data

   The EventData class has one attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.


3.15 Relating the IncidentData and EventData classes

   At first glance, the duplication in the aggregate classes of
   IncidentData and EventData are obvious.  However, the semantics of
   these classes are quite different.  IncidentData provides summary
   information about the entire incident, while EventData provides
   information about a subset of the incident.

   For example, note that the Assessment class is aggregated in both
   classes. Consider a case where IncidentData:Assessment:MonetaryImpact
   has been assigned a value of x.  Now, consider a value of y (where y
   < x) being assigned to a given MonetaryImpact class that is
   aggregated in the EventData class.  The semantics of these two values
   is some monetary loss.  In the case of the figure in the IncidentData
   class, this loss is incident-wide.  The figure in EventData is a
   subset of this overall loss, and allows one to associate a particular
   loss with a given subset of events that constitute the incident.  It
   effectively provides a breakdown (or more specific description) of



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   the overall loss previously specified in the IncidentData class.

3.16 Cardinality of EventData

   The recursive definition of this class (the EventData class is
   aggregated into the EventData class) provides a way to related
   information without requiring the explicit use of unique attribute
   identifiers in the classes. The depth of an element in the XML tree
   is used to related information.

   The EventData class can be thought of as a container describing the
   properties of an event in an incident.  These properties include: the
   hosts involved, impact of the incident activity on the hosts,
   forensic logs, etc.  One groups (via an instance of the EventData
   class) hosts (i.e., System class) around these common properties.

   A child EventData class (and all its siblings) logically "inherits"
   the aggregated classes of a parent EventData class.  However, the
   presence of sibling EventData classes (it "never" makes sense to have
   only one EventData child in an EventData class) means that there are
   some disjoin properties of the event.  These children of the parent
   EventData class represent these differences, while still retaining a
   way to represent the common properties (i.e., the parent-child
   relationship).

   For example, an EventData class might be used to describe two
   machines involved in an incident.  This description can be achieved
   using multiple instances of the System class.  It happens that the
   technical contact (i.e., Contact class) for these two machines is
   identical, but the impact (i.e., Assessment class) is different.  The
   problem lies in representing two hosts with a common contact, but
   different impacts without duplicating any information.  This event
   can be represent with the following design represented in Figure 24.


















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   +------------------+
   | EventData        |
   +------------------+
   |                  |<>----[ Contact    ]
   |                  |
   |                  |<>----[ EventData  ]<>----[ System     ]
   |                  |      [            ]<>----[ Assessment ]
   |                  |
   |                  |<>----[ EventData  ]<>----[ System     ]
   |                  |      [            ]<>----[ Assessment ]
   +------------------+

              Figure 24: Recursion in the EventData class


3.17 System class

   The System class represents the technical information for a given
   computer or network involved in the incident.

   The systems represented by this class are categorized according to
   the role they played in the incident via through the category
   attribute.  The value of this category attribute dictates the
   semantics of the aggregated classes in the System class.

   The meaning of the Node, User, Process, and Service class depend on
   the value of the category attribute of the System class.  If the
   System class category attribute is 'source', then the described
   aggregated classes denote the machine, user, process, or service from
   which the activity is originating.  With a category attribute value
   of 'target' or 'intermediary', then the described machine, user,
   process, or service is the one targeted in the activity.



















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   +------------------+
   | System           |
   +------------------+
   | ENUM restriction |<>----------[ Node     ]
   | ENUM category    |
   | STRING interface |<>--{0..*}--[ User     ]
   | ENUM spoofed     |
   |                  |<>--{0..*}--[ Process  ]
   |                  |
   |                  |<>--{0..*}--[ Service  ]
   |                  |
   |                  |<>--{0..1}--[ FileList ]
   +------------------+

                      Figure 25: the System class

   The aggregate classes that constitute System are:

   Node
      One. A host or network involved in the incident activity.

   User
      Zero or more. The application or operating system user running on
      the specified host that was involved in the incident.

   Process
      Zero or more.  The process targeted or the source of the attack on
      the specified host,

   Service
      Zero or one.  The network service targeted on the host specified
      in Node.

   FileList
      Zero or one.  Information about the files on the host involved in
      the incident.

   The System class has four attribute:

   restriction
      Optional.  ENUM.  This attribute is defined in Section 3.2.

   category
      Required.  ENUM.  Classifies the role the System played in the
      incident activity.  The possible values are:

      1.  source.  The System was the source of the attack




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      2.  target.  The System was the target of the attack

      3.  intermediate.  The System was an intermediate machine used in
          the attack.

   interface
      Optional.  STRING.  Specifies the interface on which the event(s)
      on this System originated.

   spoofed
      Optional.  ENUM.  An indication of confidence as to whether this
      System was the true target or attacking host.  The permitted
      values for this attribute are shown below.  The default value is
      "unknown".

      1.  unknown.  The accuracy of the category information is unknown

      2.  yes.  The category value classifying the host or network as an
          source or target is probably incorrect.  In the case of a
          source, the System is likely a decoy; with a target, the
          System was likely not the intended victim.

      3.  no.  The category value classifying the host or network as a
          source or target is believed to be correct.


3.18 Node class

   The Node class is used to identify a host or network device (e.g.,
   routers, switches).

   The base definition of the class is reused from the IDMEF
   specification, see Section 4.2.7.1 of [7]. However, the class has
   been extended by adding the NodeRole class.

















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   +---------------+
   |     Node      |
   +---------------+
   | ENUM category |<>--{0..1}--[ Location ]
   |               |
   |               |<>--{0..1}--[ name     ]
   |               |
   |               |<>--{0..*}--[ Address  ]
   |               |
   |               |<>--{0..1}--[ DateTime ]
   |               |
   |               |<>--{0..*}--[ NodeRole ]
   +---------------+

                       Figure 26: The Node class

   The aggregate classes that constitute Node are:

   Location
      Zero or one.  STRING. The physical location of the equipment.

   name
      Zero or one.  STRING. The name of the equipment (e.g., fully
      qualified domain name).  This information MUST be provided if no
      Address information is given.

   Address
      Zero or more.  The network or hardware address of the equipment.
      Unless a name is provided, at least one address must be specified.

   DateTime
      Zero or one.  A timestamp of when the resolution between the name
      and address was performed.  This information SHOULD be provided if
      both an Address and name are given.

   NodeRole
      Zero or more.  The intended purpose of the equipment.

   The Node class has one attribute:

   category
      Optional.  ENUM.  The context in which the Address and name
      classes should be considered, if relevant. The permitted values
      for this attribute are shown below.  The default value is
      "unknown".

      1.   unknown.  Domain unknown or not relevant




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      2.   ads.  Windows 2000 Advanced Directory Services

      3.   afs.  Andrew File System (Transarc)

      4.   coda.  Coda Distributed File System

      5.   dfs.  Distributed File System (IBM)

      6.   dns.  Domain Name System

      7.   hosts.  Local hosts file

      8.   kerberos.  Kerberos realm

      9.   nds.  Novell Directory Services

      10.  nis.  Network Information Services (Sun)

      11.  nisplus.  Network Information Services Plus (Sun)

      12.  nt.  Windows NT domain

      13.  wfw.  Windows for Workgroups


3.18.1 Address

   The Address class represents a network, hardware, and application
   address.  This class is reused outright from the IDMEF specification,
   see Section 4.2.7.1.1 of [7].

3.18.2 NodeRole class

   The NodeRole class describes (based on a pre-defined list) the
   function performed by a particular host.
















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         +---------------+
         | NodeRole      |
         +---------------+
         | STRING        |
         |               |
         | ENUM category |
         +---------------+

                     Figure 27: The NodeRole class

   The element content should be empty in all cases other than when the
   category attribute is set to "other".

   The NodeRole class has one attributes:

   category
      Required.  Functionality provided by a node.  If a value of
      "other" is specified, a description SHOULD be provided in the
      element's content.  The default value is "other".

      1.   client.  Client computer

      2.   server-internal.  Server with internal services

      3.   server-public.  Server with public services

      4.   www.  WWW server

      5.   mail.  Mail server

      6.   messaging.  Messaging server (e.g. NNTP, IRC, IM)

      7.   streaming.  Streaming-media server

      8.   voice.  Voice server (e.g. SIP, H.323)

      9.   file.  File server (e.g. SMB, CVS, AFS)

      10.  ftp.  FTP server

      11.  p2p.  Peer-to-peer node

      12.  name.  Name server (e.g. DNS, WINS)

      13.  directory.  Directory server (e.g. LDAP, finger, whois)

      14.  credential.  Credential server (e.g. domain controller,
           Kerberos)



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      15.  print.  Print server

      16.  application.  Application server

      17.  database.  Database server

      18.  infra.  Infrastructure server (e.g. router, firewall, DHCP)

      19.  log.  Logserver

      20.  other.  other role not in this list


3.19 FileList class

   The FileList class describes files and other file-like objects on
   hosts involved in an incident.  This class is reused outright from
   the IDMEF specification, see Section 4.2.7.5 of [7].

3.20 User

   The User class describes an application or operating system user
   account involved in an incident.  This class is reused outright from
   the IDMEF specification, see Section 4.2.7.2 of [7].

3.21 Process

   The Process class describes a running program on a given host
   involved in an incident.  This class is reused outright from the
   IDMEF specification, see Section 4.2.7.3 of [7].

3.22 Service

   The Service class describes a network service of a host. This class
   is reused outright from the IDMEF specification, see Section 4.2.7.4
   of [7].

3.23 Record class

   The Record class groups log or audit data that provides a record of
   the incident activity.  The source of this data will typically be the
   output of monitoring tools (e.g., IDMEF messages generated by an IDS,
   connection logs from a web server) that were used to uncover the
   malicious activity.  These logs should provide evidence as to why a
   reporter to CSIRT believes an incident has occurred.






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   +------------------+
   | Record           |
   +------------------+
   | ENUM restriction |<>--{1..*}--[ RecordData ]
   +------------------+

                        Figure 28: Record class

   The aggregate class that constitutes Record is:

   RecordData
      One or more.  Log or audit data generated by a particular type of
      sensor.

   The Record class has one attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.


3.23.1 RecordData class

   The RecordData class groups log or audit data from a given sensor
   (e.g., IDS, firewall log) and provides a way to annotate the output.


   +------------------+
   | RecordData       |
   +------------------+
   | ENUM restriction |<>--{0..1}--[ DateTime    ]
   |                  |
   |                  |<>--{0..*}--[ Description ]
   |                  |
   |                  |<>--{0..1}--[ Analyzer    ]
   |                  |
   |                  |<>--{1..*}--[ RecordItem  ]
   +------------------+

                    Figure 29: The RecordData class

   The aggregate classes that constitutes RecordData is:

   DateTime
      Zero or one.  Timestamp information for the RecordItem data.

   Description
      Zero or more.  STRING. Free-form textual description of the
      provided RecordItem data. At minimum, this description should



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      convey the significance of the provided RecordItem data.

   Analyzer
      Zero or one.  Information about the sensor used to generate the
      RecordItem data.

   RecordItem
      One or more.  Log, audit, or forensic data.

   The RecordData class has one attributes:

   restriction
      Optional.  ENUM.  This attribute has been defined in Section 3.2.


3.23.1.1 Analyzer class

   The Analyzer class identifies the sensor (e.g., IDS, firewall, web
   server) used to generate particular log or audit data. The definition
   of the class is reused from the IDMEF specification, see Section
   4.2.7.3 of [7].  However, in this context, the definition of an
   analyzer is expanded beyond merely an IDS.

3.23.1.2 RecordItem class

   The RecordItem class provides a way to incorporate relevant logs,
   audit trails, or forensic data to support the conclusions made during
   the course of analyzing the incident.  This data can be directly
   encapsulated as part of this document, or can be referenced whereby
   using this class as merely a pointer to the relevant information.

   The dtype attribute will dictate the type of log data that will be
   found in this class.  This class is very similar to the
   AdditionalData class (Section 3.6) in that it is essentially an
   extension class that can support proprietary representations of
   security event data, not all of which is necessarily in XML.















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   +------------------+
   | RecordItem       |
   +------------------+
   | ANY              |
   |                  |
   | ENUM type        |
   +------------------+

                    Figure 30: The RecordItem class

   The Recorditem class has one attribute:

   type
      Required.  The type of data included in the element content. The
      permitted values for this attribute are shown below. The default
      value is "string".

      1.   boolean.  The element contains a boolean value, i.e., the
           strings "true" or "false"

      2.   byte.  The element content is a single 8-bit byte (see
           Section 2.2.4);

      3.   character.  The element content is a single character (see
           Section 2.2.3);

      4.   date-time.  The element content is a date-time string (see
           Section 2.2.6);

      5.   integer.  The element content is an integer (see Section
           2.2.1);

      6.   ntpstamp.  The element content is a NTP timestamp (see
           Section 2.2.7);

      7.   portlist.  The element content is a port list (see Section
           2.2.8);

      8.   real.  The element content is a real number (see xref
           target="dt_real_numbers" />);

      9.   string.  The element content is a string (see Section 2.2.3);

      10.  file.  The element content is a base64 encoded binary file;

      11.  path.  The element content is a filesystem path;

      12.  url.  The element content is a URL (see Section 2.2.13;)



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      13.  xml.  The element content is XML-tagged data (see Section 4).


















































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4. Extending the IODEF

   In order to support the changing activity of CSIRTS, the IODEF data
   model and DTD will need to evolve along with them. To allow new
   features to be added, both the data model and the DTD can be extended
   as described in this section.  As these extensions mature, they can
   then be incorporated into future versions of the specification or
   published separately.

4.1 Extending the data model

   There are two mechanisms for extending the IODEF data model:
   inheritance and aggregation.

   o  By using inheritance, new subclasses may be derived and given
      additional attributes or operations not found in the superclass.

   o  Aggregation allows for entirely new, self-contained classes to be
      created and associated with a parent class.

   Of the two extension mechanisms, inheritance is preferred, because it
   preserves the existing data model and the operations (methods)
   executed on the classes of the model. There are explicit guidelines
   for extending the XML DTD (see Section 4.2) which set limits on where
   extensions to the data model may be made.

4.2 Extending the XML DTD

   There are two ways to extend the IODEF XML DTD:

   1.  The AdditionalData (see Section 3.6) and RecordItem (see Section
       3.23.1.2) classes allow implementers to include arbitrary
       "atomic" data. (e.g., integers, strings).  This approach SHOULD
       be used whenever possible.

   2.  The AdditionalData and RecordItem classes allow implementers to
       extend the IODEF XML DTD with additional DTDs that describe
       arbitrarily complex data types and relationships.

   The following guidelines MUST be followed when extending the IODEF
   DTD with another DTD in the extension classes:


   1.  The IODEF description MUST include a document type declaration
       (see Section 2.1.1.3);

   2.  The document type declaration MUST define a parameter entity that
       contains the location of the extension DTD, and then reference



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       that entity:

    <!DOCTYPE IODEF-Document SYSTEM "/path/to/IODEF-Document.dtd"
             [ <!ENTITY % x-extension SYSTEM "/path/to/extension.dtd">
                        % x-extension;  ]>


       In this example, the "x-extension" parameter entity is defined
       and then referenced, causing the DTD for the extension to be read
       by the XML parser.
       The name of the parameter entity defined for this purpose MUST be
       a string beginning with "x-"; there are no other restrictions on
       the name (other than those imposed on all entity names by XML).
       Multiple extensions may be included by defining multiple entities
       and referencing them.  For example:

    <!DOCTYPE IODEF-Document SYSTEM "/path/to/IODEF-Document.dtd"
             [ <!ENTITY % x-extension SYSTEM "/path/to/extension.dtd">
               <!ENTITY % x-another SYSTEM "/path/to/another.dtd">
                        %x-extension;
                        %x-another;  ]>

   3.  Extension DTDs MUST declare all of their elements and attributes
       in a separate XML namespace.  Extension DTDs MUST NOT declare any
       elements or attributes in the "IODEF" or default namespaces.

       For example, the "test" extension might be declared as follows:

   <!ELEMENT test:test ( test:a, test:b, test:c )>
   <!ATTLIST test:test
      xmlns      CDATA   #IMPLIED
      xmlns:test CDATA   #IMPLIED
   >
   <!ELEMENT test:a (#PCDATA)>
   <!ATTLIST test:a
      test:attr   CDATA   #IMPLIED
   >

   <!ELEMENT test:b (#PCDATA)>
   <!ELEMENT test:c (#PCDATA)>

   4.  Extensions MUST only be included in the AdditionalData class of
       the Incident class whose "type" attribute is "xml".  For example:








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   <IODEF-Document version="0.0">
      <Incident ident="...">
         ...
         <AdditionalData type="xml">
         <test:test
            xmlns:test="http://www.ietf.org/iodef/test.html"
            xmlns="http://www.ietf.org/iodef/test.html">
            <test:a test:attr="...">...</test:a>
            <test:b>...</test:b>
            <test:c>...</test:c>
         </test:test>
         </AdditionalData>
      </Incident>
   </IODEF-Document>





































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5. Processing Considerations

   This section discusses some of the special considerations that must
   be taken into account by implementers of the IODEF.

5.1 XML Validity and Well-Formedness

   The IODEF documents MUST be well-formed, and when  possible and
   practical the documents SHOULD also be valid.

   It is expected that IODEF-compliant applications will normally not
   include the IODEF DTD in their communications.  Instead, the DTD will
   be referenced in the document type declaration section of the IODEF
   document (see Section 2.1.1.3.

   While an XML document SHOULD contain a document type declaration.
   This requirement imposes a significant overhead on an IODEF-compliant
   application in bandwidth consumption and computation for the DTD may
   need to be downloaded and parsed before use by the XML parser.

   Implementers MAY decide to have entities who regularly exchange IODEF
   message agree out-of-band on the particular document type definition
   they will be using to exchange messages (the standard one as defined
   here, or one with extensions), and then omit it from IODEF documents.
   The method for negotiating this agreement is outside the scope of
   this document.

   NOTE: Care must be taken in negotiating any such agreements, as each
   entities will have to keep state on this agreed upon document type
   definition.  The management complexity of these negotiations grows
   more complex as entities make such arrangements with many
   collaborators.

5.2 Unrecognized Data and XML Tags

   On occasion, an IODEF-compliant application may receive a well-
   formed, or well-formed and valid IODEF document containing tags or
   content in the tags that are not expected.  These spurious conditions
   might include:

   o  Unrecognized tags used in one of the extension classes (i.e.,
      AdditionalData or RecordItem);

   o  Unrecognized tags outside of the extension classes; or

   o  Well-formed and validate document where element or attribute
      values to not conform to the expected values identified by an
      enumerated list;



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   IODEF-compliant applications MUST continue to process IODEF documents
   that contain unknown tags, provided that these documents are
   well-formed.  It is up to the individual application to decide how to
   process any content from the unknown tag.















































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6. Internationalization issues

   Internationalization and localization is of specific concern to the
   IODEF.  It is only through collaboration, often across language
   barriers, that certain incidents be resolved.

   XML already supports different character encodings.  This flexibility
   will allow information encoded in the IODEF to be in most written
   languages. Furthermore, XML also provides the xml:lang attribute
   through which the type of language being used in a given element can
   be specified.  By including this attribute in the %attlist.global
   entity found in all elements, users of the IODEF can use different
   languages in the same document.

   The data model ensures that the cardinality of the Description class
   is always one-to-many with its parent.  One of the intents for this
   design was to allow the same description to be repeated in another
   instance of the Description class, but in a different language.
   Parsers of the IODEF document, could extract only the elements with
   the relevant language.

   Supporting different languages allows CSIRTs to localize the IODEF.
   However, it does not aid data interchange if the recipient of a
   document does not understand the underlying language.  In order to
   ensure that the recipient can at least crudely approximate the
   contents of the document, the data model relies on enumerated
   attributes that are standardized to convey meaning (e.g.,
   %attlist.purpose).























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7. Examples

   These examples provide an idea of what IODEF-Documents can look like.
   It must be stressed that as IODEF is a data-exchange-format, it does
   not specify detailed rules on which elements and attributes to use
   under all imaginable circumstances.

7.1 Code Red detection notification

   The following message is a typical example of an incident where one
   host is infected with a worm.  The initial report is sent in by
   email, the subsequently shown IODEF-Document illustrates the
   communication between the responsible CSIRT and its constituent.  The
   constituent is a contact for the CSIRT and responsible for
   coordinating the required actions at his site.


   From e-citizen@hisdomain.de
   Date: 13 Sep 2001 23:19:24 -0000
   From: e-citizen@hisdomain.de
   To: cert-for-ourdomain.pl@ourdomain.pl
   Subject: 10.1.1.2 - Code Red Virus detected

   Automated message,
   you don't have to reply to this email.

   Your system with the IP number 10.1.1.2 seems to be infected
   with the Code Red virus.

   For more information see http://www.incidents.org/react/code_redII.php

   Please fix the problem or inform a person who is responsible
   for that machine to do so.

   >From our web server logs (Port 80):
   10.1.1.2 - - [13/Sep/2001:18:11:21 +0200] "GET /default.ida?XXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

       Figure 35: Code Red detection notification: initial report



   <IODEF-Document version="1.0">
      <Incident restriction="need-to-know" purpose="handling">
         <IncidentID
   name="CERT-FOR-OUR-DOMAIN.PL">CERT-FOR-OUR-DOMAIN.PL#189</IncidentID>



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         <IncidentData>
            <Description>Host sending out Code Red probes</Description>
            <ReportTime>2001-09-13T23:19:24+00:00</ReportTime>
            <Expectation category="other">
               <Description>Track and clean host</Description>
            </Expectation>
            <Assessment>
               <Impact severity="low" completion="failed"
   type="none"></Impact>
            </Assessment>
            <Contact role="creator" role="irt" type="organization">
               <name>CERT-FOR-OUR-DOMAIN.PL</name>
               <Email>cert-for-our-domain.pl@ourdomain.pl</Email>
            </Contact>
            <Contact role="tech" type="organization">
               <name>Constituency-contact for 10.1.1.2</name>
               <Email>Constituency-contact@10.1.1.2.pl</Email>
            </Contact>
            <History>
               <HistoryItem type="notification">
                  <IncidentID
   name="CERT-FOR-OUR-DOMAIN.PL">CERT-FOR-OUR-DOMAIN.PL#189</IncidentID>
                  <Description>Notification sent to
   Constituency-contact@10.1.1.2.pl</Description>
                  <DateTime>2001-09-14T08:19:01+00:00</DateTime>
               </HistoryItem>
            </History>
            <EventData>
               <System category="source">
                  <Node>
                     <Address category="ipv4-addr">10.1.1.2</Address>
                  </Node>
               </System>
               <System category="target">
                  <Service>
                     <port>80</port>
                  </Service>
               </System>
               <Record>
                  <RecordData>
                     <DateTime>2001-09-13T18:11:21+02:00</DateTime>
                     <Description>Web-server logs</Description>
                     <RecordItem>
   10.1.1.2 - - [13/Sep/2001:18:11:21 +0200] "GET /default.ida?XXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
                     </RecordItem>



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                  </RecordData>
               </Record>
            </EventData>
         </IncidentData>
      </Incident>
   </IODEF-Document>


       Figure 36: Code Red detection notification: CSIRT response


7.2 IODEF-Document with XML signature

7.3 IODEF-Document encrypted using XML encryption

7.4 IODEF-Document encrypted and signed using XML signature & encryption



































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8. The IODEF Document Type Definition


   <?xml version="1.0" encoding="UTF-8"?>
   <!--
    ********************************************************************
    ********************************************************************
    *** IncidentData Exchange Format XML DTD                         ***
    ***               Version 01, March 2003                         ***
    ********************************************************************
    ********************************************************************
    -->
   <!--
    ====================================================================
    === SECTION 1. Attribute list declarations.                      ===
    ====================================================================
    -->
   <!--
    | Attributes of the IODEF element.  In general, the fixed value
    | of this attribute will change each time a new version of
    | the DTD is released.
    -->
   <!ENTITY % attlist.iodef "
         version             CDATA                   #FIXED    '0.10'
      ">
   <!--
    ====================================================================
    === SECTION 2. Attribute value declarations.  Enumerated values  ===
    ===            for the many element-specific attribute lists.    ===
    ====================================================================
    -->
   <!--
    | Defines purpose of the Incident
    -->
   <!ENTITY % attvals.purpose "
         ( handling | statistics | warning | other )
      ">
   <!--
    | Defines restriction on access to an element's content
    -->
   <!ENTITY % attvals.restriction "
         ( default | public | need-to-know | private )
      ">
   <!--
    | Values for the Expectation.category attributes
    -->
   <!ENTITY % attvals.expectations "
         ( nothing | contact-site | contact-me | block | other )



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      ">
   <!--
    | Values for the AdditionalData.type attribute.
    -->
   <!ENTITY % attvals.adtype "
         ( boolean | byte | character | date-time | integer |
           ntpstamp | portlist | real | string | xml )
       ">
   <!--
    | Values for the RecordItem.type attribute
    -->
   <!ENTITY % attvals.dtype "
         ( boolean | byte | character | date-time | integer |
           ntpstamp | portlist | real | string | file | path | url |
        xml )
        ">
   <!--
    | Values for the History.type attribute.
    -->
   <!ENTITY % attvals.historycat "
          ( triaged | notification | shared-info | received-info |
            remediation | other )
         ">
   <!--
    | Values for the Address.category attribute.
    -->
   <!ENTITY % attvals.addrcat "
         ( unknown | atm | e-mail | lotus-notes | mac | sna | vm |
           ipv4-addr | ipv4-addr-hex | ipv4-net | ipv4-net-mask |
           ipv6-addr | ipv6-addr-hex | ipv6-net | ipv6-net-mask )
       ">
   <!--
    | Values for the Id.type attribute.
    -->
   <!ENTITY % attvals.idtype "
         ( current-user | original-user | target-user | user-privs |
           current-group | group-privs )
       ">
   <!--
    | Values for the Impact.completion attribute.
    -->
   <!ENTITY % attvals.completion "
          ( failed | succeeded )
        ">
   <!--
    | Values for the File.category attribute.
    -->
   <!ENTITY % attvals.filecat "



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          ( current | original )
        ">
   <!--
    | Values for the Impact.type attribute.
    -->
   <!ENTITY % attvals.impacttype "
          ( none | admin | dos | file | recon | user | unknown |
            other )
        ">
   <!--
    | Values for the Linkage.category attribute.
    -->
   <!ENTITY % attvals.linkcat "
          ( hard-link | mount-point | reparse-point | shortcut |
            stream | symbolic-link )
        ">
   <!--
    | Values for the RegistryHandle.type attribute.
    -->
   <!ENTITY % attvals.registrytype "
      ( internic | apnic | arin | lacnic | ripe | ti | local )
    ">
   <!--
    | Values for the Confidence.rating attribute.
    -->
   <!ENTITY % attvals.rating "
          ( low | medium | high | numeric | unknown )
        ">
   <!--
    | Values for the Impact.severity attribute.
    -->
   <!ENTITY % attvals.severity "
          ( low | medium | high )
        ">
   <!--
    | Values for the Node.category attribute.
    -->
   <!ENTITY % attvals.nodecat "
         ( unknown | ads | afs | coda | dfs | dns | hosts |
           kerberos | nds | nis | nisplus | nt | wfw )
       ">
   <!--
    | Values for the NodeRole.category attribute.
    -->
   <!ENTITY % attvals.noderolecat "
        ( client | server-internal | server-public | www | mail |
          messaging | streaming | voice | file | ftp | p2p | name |
          directory | credential | print | application | database |



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          infra | log | other )
       ">
   <!--
    | Values for the Classification.origin attribute.
    -->
   <!ENTITY % attvals.origin "
         ( bugtraqid | cve | certcc | vendor | local | other)
      ">
   <!--
    | Values for the User.category attribute.
    -->
   <!ENTITY % attvals.usercat "
         ( unknown | application | os-device )
      ">
   <!--
    | Values for the System.spoofed and System.decoy attributes
    -->
   <!ENTITY % attvals.yesno "
         ( unknown | yes | no )
      ">
   <!--
    | Values for the System.category attribute
    -->
   <!ENTITY % attvals.systemcat "
        ( source | target | intermediate )
        ">
   <!--
    ====================================================================
    ==  Element definitions                                           ==
    ====================================================================
    -->
   <!--
    ====================================================================
    == IODEF-Document class                                           ==
    ====================================================================
    -->
   <!ELEMENT IODEF-Document (Incident+)>
   <!ATTLIST IODEF-Document
        %attlist.iodef;
        xmlns:iodef CDATA             #FIXED  'urn:iana:xml:ns:iodef'
   >
   <!--
    ====================================================================
    ==  Incident class                                                ==
    ====================================================================
    -->
   <!ELEMENT Incident (IncidentID, AlternativeID?, RelatedActivity?,
                       IncidentData, AdditionalData*)>



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   <!ATTLIST Incident
        restriction  %attvals.restriction; "private"
        purpose      %attvals.purpose;     #REQUIRED
   >
   <!--
    ====================================================================
    ==  IncidentID class                                              ==
    ====================================================================
    -->
   <!ELEMENT IncidentID (#PCDATA)>
   <!ATTLIST IncidentID
        name        CDATA                 #IMPLIED
        restriction %attvals.restriction; #IMPLIED
   >
   <!--
    ====================================================================
    ==  AlternativeID class                                           ==
    ====================================================================
    -->
   <!ELEMENT AlternativeID (IncidentID+)>
   <!ATTLIST AlternativeID
        restriction %attvals.restriction; #IMPLIED
   >
   <!--
    ====================================================================
    ==  RelatedActivity class                                         ==
    ====================================================================
    -->
   <!ELEMENT RelatedActivity (IncidentID+)>
   <!ATTLIST RelatedActivity
        restriction %attvals.restriction; #IMPLIED
   >
   <!--
    ====================================================================
    ===  AdditionalData class                                        ===
    ====================================================================
    -->
   <!ELEMENT AdditionalData ANY>
   <!ATTLIST AdditionalData
        restriction %attvals.restriction; #IMPLIED
        type     %attvals.adtype; #REQUIRED
        meaning  CDATA            #IMPLIED
   >
   <!--
    ====================================================================
    ===  IncidentData class                                          ===
    ====================================================================
    -->



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   <!ELEMENT IncidentData (Description*, Contact+, ReportTime,
                           DetectTime?, StartTime?, EndTime?,
                           Expectation*, Method*, Assessment+,
                           EventData*, History?, AdditionalData*)>
   <!ATTLIST IncidentData
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!--
    ====================================================================
    ===  Contact class                                               ===
    ===    - RegistryHandle
    ===    - PostalAddress
    ===    - Email
    ===    - Telephone
    ===    - Fax
    ====================================================================
    -->
   <!ELEMENT Contact (name?, Description*, RegistryHandle*,
                      PostalAddress?, Email*, Telephone*, Fax?,
                   Contact*)>
   <!ATTLIST Contact
        role        (creator | admin | tech | irt | cc) #REQUIRED
        type        (person | organization)             #REQUIRED
        restriction %attvals.restriction;               #IMPLIED
   >
   <!ELEMENT RegistryHandle (#PCDATA)>
   <!ATTLIST RegistryHandle
        type  %attvals.registrytype;  "local"
   >
   <!ELEMENT PostalAddress (#PCDATA)>
   <!ATTLIST PostalAddress
        lang  NMTOKEN  #IMPLIED
   >
   <!ELEMENT Email (#PCDATA)>
   <!ELEMENT Telephone (#PCDATA)>
   <!ELEMENT Fax (#PCDATA)>
   <!--
    ====================================================================
    ===  Time-based classes                                          ===
    ===    - DateTime
    ===    - ReportTime
    ===    - DetectTime
    ===    - StartTime
    ===    - EndTime
    ====================================================================
    -->
   <!ELEMENT DateTime (#PCDATA)>
   <!ATTLIST DateTime



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        ntpstamp  CDATA  #IMPLIED
   >
   <!ELEMENT ReportTime (#PCDATA)>
   <!ATTLIST ReportTime
        ntpstamp  CDATA  #IMPLIED
   >
   <!ELEMENT DetectTime (#PCDATA)>
   <!ATTLIST DetectTime
        ntpstamp CDATA #IMPLIED
   >
   <!ELEMENT StartTime (#PCDATA)>
   <!ATTLIST StartTime
        ntpstamp  CDATA  #IMPLIED
   >
   <!ELEMENT EndTime (#PCDATA)>
   <!ATTLIST EndTime
        ntpstamp  CDATA  #IMPLIED
   >
   <!--
    ====================================================================
    ===  History class                                               ===
    ===    - HistoryItem
    ====================================================================
    -->
   <!ELEMENT History (HistoryItem+)>
   <!ATTLIST History
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!ELEMENT HistoryItem (DateTime, IncidentID?, Description+)>
   <!ATTLIST HistoryItem
        type         %attvals.historycat;   #IMPLIED
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!--
    ====================================================================
    ===  Expectation class                                           ===
    ====================================================================
    -->
   <!ELEMENT Expectation (Description+, Contact?, StartTime?, EndTime?)>
   <!ATTLIST Expectation
        priority    %attvals.severity;      #IMPLIED
        restriction %attvals.restriction;   #IMPLIED
        category    %attvals.expectations;  #IMPLIED
   >
   <!--
    ====================================================================
    ===  Method class                                                ===
    ===    - Classification



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    ====================================================================
    -->
   <!ELEMENT Method (Classification*, Description*)>
   <!ATTLIST Method
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!ELEMENT Classification (name, url)>
   <!ATTLIST Classification
        restriction  %attvals.restriction;  #IMPLIED
        origin %attvals.origin; "other"
   >
   <!--
    ====================================================================
    ===  Assessment class                                            ===
    ===    - Impact
    ===    - TimeImpact
    ===    - MonetaryImpact
    ===    - LifeImpact
    ===    - Confidence
    ====================================================================
    -->
   <!ELEMENT Assessment (Impact*, TimeImpact*, MonetaryImpact*,
                         LifeImpact*, Confidence?)>
   <!ATTLIST Assessment
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!ELEMENT Impact (#PCDATA)>
   <!ATTLIST Impact
        restriction  %attvals.restriction;  #IMPLIED
        severity   %attvals.severity;       #IMPLIED
        completion %attvals.completion;     #IMPLIED
        type       %attvals.impacttype;     "unknown"
        lang       NMTOKEN                  #IMPLIED
   >
   <!ELEMENT TimeImpact (#PCDATA)>
   <!ATTLIST TimeImpact
        restriction  %attvals.restriction;        #IMPLIED
        severity  %attvals.severity;              #IMPLIED
        unit   (labor | elapsed | downtime)       #REQUIRED
        metric (days | hours | minutes | seconds) "hours"
   >
   <!ELEMENT MonetaryImpact (#PCDATA)>
   <!ATTLIST MonetaryImpact
        restriction  %attvals.restriction;  #IMPLIED
        severity %attvals.severity;         #IMPLIED
        currency   CDATA                    #REQUIRED
   >
   <!ELEMENT LifeImpact (#PCDATA)>



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   <!ATTLIST LifeImpact
        restriction  %attvals.restriction;  #IMPLIED
        severity %attvals.severity;         #IMPLIED
        metric (deaths | injuries)          #REQUIRED

   >
   <!ELEMENT Confidence EMPTY>
   <!ATTLIST Confidence
        rating  %attvals.rating;    #REQUIRED
   >
   <!--
    ====================================================================
    === EventData class                                              ===
    ====================================================================
    -->
   <!ELEMENT EventData (Description*, Contact*, ReportTime?,
                        DetectTime?, StartTime?, EndTime?, Expectation?,
                     System*, Method*, Assessment?, EventData*,
                     History?, Record?, AdditionalData*)>
   <!ATTLIST EventData
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!--
    ====================================================================
    ===  System class                                                ===
    ====================================================================
    -->
   <!ELEMENT System (Node, User*, Process*, Service*, FileList?)>
   <!ATTLIST System
        category     %attvals.systemcat;    #IMPLIED
        spoofed      %attvals.yesno;        "unknown"
        interface    CDATA                  #IMPLIED
        restriction  %attvals.restriction;  #IMPLIED
   >
   <!--
    ====================================================================
    ===  FileList class                                              ===
    ===    - File
    ===        - access-time
    ===        - change-time
    ===        - create-time
    ===        - modify-time
    ===        - c-major-device
    ===        - c-minor-device
    ===        - data-size
    ===        - disk-size
    ====================================================================
    -->



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   <!ELEMENT FileList (File+)>
   <!ENTITY % attvals.filecat "
          ( current | original )
           ">
   <!ELEMENT File (name, path, create-time?, modify-time?, access-time?,
                   data-size?, disk-size?, FileAccess*, Linkage*,
                Inode)>
   <!ATTLIST File
        ident     CDATA             "0"
        category  %attvals.filecat; #REQUIRED
        fstype    CDATA             #REQUIRED
   >
   <!ELEMENT access-time (#PCDATA)>
   <!ELEMENT change-time (#PCDATA)>
   <!ELEMENT create-time (#PCDATA)>
   <!ELEMENT modify-time (#PCDATA)>
   <!ELEMENT c-major-device (#PCDATA)>
   <!ELEMENT c-minor-device (#PCDATA)>
   <!ELEMENT data-size (#PCDATA)>
   <!ELEMENT disk-size (#PCDATA)>
   <!ELEMENT major-device (#PCDATA)>
   <!ELEMENT minor-device (#PCDATA)>
   <!ELEMENT Linkage ((name, path) | File)>
   <!ATTLIST Linkage
        category  %attvals.linkcat;  #REQUIRED
   >
   <!ELEMENT FileAccess (UserId, permission+)>
   <!ELEMENT Inode (change-time?, (number, major-device, minor-device)?,
                    (c-major-device, c-minor-device)?)>

   <!--
    ====================================================================
    ===  FileList class                                              ===
    ===      - NodeRole
    ===      - Location
    ===      - name
    ====================================================================
    -->
   <!ELEMENT Node (((name | Address), Address*), DateTime?,
                   name?, Address*, Location?, NodeRole*)>
   <!ATTLIST Node
        category %attvals.nodecat; "unknown"
   >
   <!ELEMENT Address (address, netmask?)>
   <!ATTLIST Address
        ident     CDATA "0"
        category  %attvals.addrcat; "unknown"
        vlan-name CDATA #IMPLIED



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        vlan-num  CDATA #IMPLIED
   >
   <!ELEMENT address (#PCDATA)>
   <!ELEMENT netmask (#PCDATA)>
   <!ELEMENT Location (#PCDATA)>
   <!ATTLIST Location
        lang  NMTOKEN  #IMPLIED
   >
   <!ELEMENT NodeRole (#PCDATA)>
   <!ATTLIST NodeRole
        category %attvals.noderolecat; "other"
        lang  NMTOKEN  #IMPLIED
   >

   <!--
    ====================================================================
    ===  User class                                                  ===
    ===   - UserID
    ====================================================================
    -->
   <!ELEMENT User (UserId+)>
   <!ATTLIST User
        ident     CDATA             "0"
        category  %attvals.usercat; "unknown"
   >
   <!ELEMENT UserId (name | number | (name, number))>
   <!ATTLIST UserId
        ident CDATA "0"
        type %attvals.idtype; "original-user"
   >
   <!ELEMENT number (#PCDATA)>

   <!--
    ====================================================================
    ===  Process class                                               ===
    ====================================================================
    -->
   <!ELEMENT Process (name, pid?, path?, arg*, env*)>
   <!ATTLIST Process
        ident CDATA "0"
   >
   <!ELEMENT env (#PCDATA)>
   <!ELEMENT pid (#PCDATA)>

   <!--
    ====================================================================
    ===  Service Class                                               ===
    ===    - port



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    ===    - portlist
    ===    - protocol
    ===    - SNMPService
    ===    - WebService
    ===        - url, cgi, arg, http-method
    ===    - SNMPService
    ===        - oid, community, command
    ====================================================================
    -->
   <!ELEMENT Service (((name | port | (name, port)) | portlist),
                      protocol?, SNMPService?, WebService?)>
   <!ATTLIST Service
        ident CDATA "0"
   >
   <!ELEMENT port (#PCDATA)>
   <!ELEMENT portlist (#PCDATA)>
   <!ELEMENT protocol (#PCDATA)>
   <!--
    ====== Web Service ======
    -->
   <!ELEMENT WebService (url, cgi?, http-method?, arg*)>
   <!ELEMENT cgi (#PCDATA)>
   <!ELEMENT arg (#PCDATA)>
   <!ELEMENT http-method (#PCDATA)>
   <!--
    ====== SNMPService ======
    -->
   <!ELEMENT SNMPService (oid?, community?, command?)>
   <!ELEMENT oid (#PCDATA)>
   <!ELEMENT community (#PCDATA)>
   <!ELEMENT command (#PCDATA)>
   <!--
    ====================================================================
    ===  Record class                                                ===
    ===    - RecordData
    ===    - Analyzer
    ===    - RecordItem
    ====================================================================
    -->
   <!ELEMENT Record (RecordData+)>
   <!ATTLIST Record
        restriction %attvals.restriction; #IMPLIED
   >
   <!ELEMENT RecordData (Description*, DateTime?, Analyzer?,
             RecordItem?)>
   <!ATTLIST RecordData
        ident       CDATA                 "0"
        restriction %attvals.restriction; #IMPLIED



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   >
   <!--Element Analyzer of IODEF is re-used from IDMEF-->
   <!ELEMENT Analyzer (Node?, Process?)>
   <!ATTLIST Analyzer
        analyzerid    CDATA  "0"
        manufacturer  CDATA  #IMPLIED
        model         CDATA  #IMPLIED
        version       CDATA  #IMPLIED
        class         CDATA  #IMPLIED
        ostype        CDATA  #IMPLIED
        osversion     CDATA  #IMPLIED
   >
   <!ELEMENT RecordItem ANY>
   <!ATTLIST RecordItem
        dtype  %attvals.dtype;  #REQUIRED
   >
   <!--
    ====================================================================
    === Miscellaneous simple classes                                 ===
    ===   - Description
    ===   - name
    ===   - path
    ===   - url
    ====================================================================
    -->
   <!ELEMENT Description ANY>
   <!ATTLIST Description
        lang  NMTOKEN  #IMPLIED
   >
   <!ELEMENT name (#PCDATA)>
   <!ATTLIST name
        lang  NMTOKEN  #IMPLIED
   >
   <!ELEMENT path (#PCDATA)>
   <!ELEMENT url (#PCDATA)>
















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9. Security considerations

   Due to the sensitive nature of some of the data that might be
   represented in the IODEF, the integrity, confidentiality, and
   non-repudiation of these documents in transit SHOULD be ensured.
   Although this protection can be provided by the transport mechanism,
   applying this security to an instance of the IODEF itself is
   RECOMMENDED.  However, the specific protective measures applied to an
   IODEF document (be in through XML or the underlying transport
   protocol) should be driven by the requirements of the collaborators.

   The applied protective measures MUST use cryptographic techniques.
   XML  Digital Signatures [16] SHOULD be used for ensuring integrity
   and non-repudiation, and XML Encryption [17] SHOULD be used to ensure
   the confidentiality of an IODEF document.  Examples using signatures
   and encryption on an IODEF document can be found in the Examples
   chapter (Section 7):

   o  IODEF-Document with XML signature (Section 7.2)

   o  IODEF-Document encrypted using XML encryption (Section 7.3)

   o  IODEF-Document encrypted and signed using XML signature &
      encryption (Section 7.4)

   Information on the implementation-specifics of applying XML Digital
   Signatures and XML Encryption to an IODEF-Document can be found in
   the IODEF Implementation Guide [20].

   When using cryptographic techniques the issue of key management
   (whether symmetric or public key cryptography is used) must be
   addressed.

   Overall security measures must be applied to secure the
   IODEF-Document processing environment.  The definition of these
   measures is outside the scope of this memo.















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10. IANA considerations


















































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11. Acknowledgments

   The following groups contributed substantially to this document and
   should be recognized for their efforts. This document would not exist
   without their help:

   o  the Incident Object Description and Exchange Format Working-Group
      of the TERENA task-force (TF-CSIRT)

   o  the eCSIRT.net project









































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Normative References

   [1]   Demchenko, Y., Hiroyuki, H. and G. Keeni, "Requirements for
         Format for Incident Report Exchange", RFC XXX, September 2003.

   [2]   World Wide Web Consortium, "Extensible Markup Language (XML)
         1.0 (Second Edition)", , October 2000, <http://www.w3.org/TR/
         2000/REC-xml-20001006>.

   [3]   World Wide Web Consortium, "Namespaces in XML", , January 1999,
         <http://www.w3.org/TR/REC-xml-names/>.

   [4]   World Wide Web Consortium, "Extensible Stylesheet Language
         (XSL) Version 1.0", , October 2001, <http://www.w3.org/TR/xsl/
         >.

   [5]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", RFC 2119, March 1997.

   [6]   Alvestrand, H., "Tags for the Identification of Languages", RFC
         3066, January 2001.

   [7]   Curry, D. and H. Debar, "Intrusion Detection Message Exchange
         Format", RFC XXX, January 2003.

   [8]   Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
         Resource Identifiers (URI): Generic Syntax", RFC 2396, August
         1998.

   [9]   Freed, N., "IANA Charset Registration Procedures", BCP 2278,
         January 1998.

   [10]  Mills, D., "Network Time Protocol (Version 3) Specification,
         Implementation, and Analysis", BCP 2278, March 1992.

   [11]  Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for
         IPv4, IPv6 and OSI", RFC 2030, October 1996.

   [12]  Wahl, M., "A Summary of the X.500(96) User Schema for use with
         LDAPv3", RFC 2256, December 1997.

   [13]  Resnick, P., "Internet Message Format", RFC 2822, April 2001.

   [14]  Klyne, G. and C. Newman, "Date and Time on the Internet:
         Timestamps", RFC 3339, July 2002.

   [15]  International Organization for Standardization, "International
         Standard: Data elements and interchange formats -  Information



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         interchange - Representation of dates and times", ISO 8601,
         Second Edition, December 2000.

   [16]  Eastlake 3rd, D., Reagle, J. and D. Solo, "(Extensible Markup
         Language) XML-Signature Syntax and Processing", RFC 3275, March
         2002.

   [17]  Imamura, T., Dillaway, B. and E. Simon, "XML Encryption Syntax
         and Processing, W3C Recommendation", December 2002, <http://
         www.w3.org/TR/2002/REC-xmlenc-core-20021210/>.

   [18]  International Organization for Standardization, "International
         Standard: Codes for the representation of currencies and funds,
         ISO 4217:2001", ISO 4217:2001, August 2001.





































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Informative References

   [19]  Rumbaugh, J., Jacobson, I. and G. Booch, "The Unified Modeling
         Language Reference Model, ISBN 020130998X, Addison-Wesley",
         1998.

   [20]  Helme, A. and R. Danyliw, "The IODEF Implementation Guide,
         document to be created by the INCH WG", 2003.


Authors' Addresses

   Jan Meijer
   SURFnet bv
   P.O. Box 19035
   Utrecht  NL-3501 DA
   Netherlands

   Phone: +31 302 305 305
   EMail: jan.meijer@surfnet.nl


   Roman Danyliw
   CERT Coordination Center
   4500 Fifth Ave.
   Pittsburgh, PA  15213
   USA

   Phone: +1 412 268 7090
   EMail: rdd@cert.org


   Yuri Demchenko
   NLnet Labs
   Netherlands

   EMail: demch@chello.nl














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Intellectual Property Statement

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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































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