Intrusion Detection Message Exchange Format

Used as part of computer security, IDMEF (Intrusion Detection Message Exchange Format) is a data format used to exchange information between software enabling intrusion detection, intrusion prevention, security information collection and management systems that may need to interact with them. IDMEF messages are designed to be processed automatically. The details of the format are described in the RFC 4765. This RFC presents an implementation of the XML data model and the associated DTD. The requirements for this format are described in RFC 4766, and the recommended transport protocol (IDXP) is documented in RFC 4767

IDMEF

The purpose of IDMEF is to define data formats and exchange procedures for sharing information of interest to intrusion detection and response systems and to the management systems that may need to interact with them. It is used in computer security for incidents reporting and exchanging. It is intended for easy automatic processing.

IDMEF is a well-structured object-oriented format, which consists of 33 classes containing 108 fields, including three mandatory:

  • The classification
  • The unique login
  • The date of creation of the alert.

There are currently two types of IDMEF messages that can be created, Heartbeat or Alert

Heartbeat

The Heartbeats are sent by the analyzers to indicate their status. These messages are sent at regular intervals which period is defined in the Heartbeat Interval Field. If none of these messages are received for several periods of time, consider that this analyzer is not able to trigger alerts.

Alert

Alerts are used to describe an attack that took place, the main areas that create the alert are:

  • CreateTime: Date of creation of the alert
  • DetectTime: alert detection time by the analyzer
  • AnalyzerTime: The time the alert was sent by the analyzer
  • Source: Details about the origin of the attack can be a service, a user, a process and / or a node
  • Target: Details on the target of the attack can be a service, a user, a process and / or a node and a file
  • Classification: Name of the attack and references, as CVEs
  • Assessment: Evaluation of the attack (severity, potential impact, etc.)
  • AdditionalData: Additional information on the attack

There are three other alert types that inherit from this scheme:

  • CorrelationAlert: Grouping of alerts related to one another
  • ToolAlert: alerts from the same Grouping tool
  • OverflowAlert: Alert resulting from attack so-called buffer overflow

Example

IDMEF report of ping of death attack can look as follows:

<?xml version="1.0" encoding="UTF-8"?>
<idmef:IDMEF-Message xmlns:idmef="http://iana.org/idmef" version="1.0">
  <idmef:Alert messageid="abc123456789">
    <idmef:Analyzer analyzerid="bc-sensor01">
      <idmef:Node category="dns">
        <idmef:name>sensor.example.com</idmef:name>
      </idmef:Node>
    </idmef:Analyzer>
    <idmef:CreateTime ntpstamp="0xbc71f4f5.0xef449129">2000-03-09T10:01:25.93464Z</idmef:CreateTime>
    <idmef:Source ident="a1a2" spoofed="yes">
      <idmef:Node ident="a1a2-1">
        <idmef:Address ident="a1a2-2" category="ipv4-addr">
          <idmef:address>192.0.2.200</idmef:address>
        </idmef:Address>
      </idmef:Node>
    </idmef:Source>
    <idmef:Target ident="b3b4">
      <idmef:Node>
        <idmef:Address ident="b3b4-1" category="ipv4-addr">
          <idmef:address>192.0.2.50</idmef:address>
        </idmef:Address>
      </idmef:Node>
    </idmef:Target>
    <idmef:Target ident="c5c6">
      <idmef:Node ident="c5c6-1" category="nisplus">
        <idmef:name>lollipop</idmef:name>
      </idmef:Node>
    </idmef:Target>
    <idmef:Target ident="d7d8">
      <idmef:Node ident="d7d8-1">
        <idmef:location>Cabinet B10</idmef:location>
        <idmef:name>Cisco.router.b10</idmef:name>
      </idmef:Node>
    </idmef:Target>
    <idmef:Classification text="Ping-of-death detected">
      <idmef:Reference origin="cve">
        <idmef:name>CVE-1999-128</idmef:name>
        <idmef:url>http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-1999-128</idmef:url>
      </idmef:Reference>
    </idmef:Classification>
  </idmef:Alert>
</idmef:IDMEF-Message>

Tools implementing the IDMEF protocol

Competing Frameworks

Many telecommunications network elements produce security alarms[1] that address intrusion detection in conformance with international standards. These security alarms are inserted into the normal alarm stream[2], where they can be seen and acted upon immediately by personnel in a Network operations center.

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gollark: Over time, tons of the stuff which people said was opaque to study (and which was ascribed to god or whatever mostly) has turned out to actually be entirely possible to study.
gollark: It's not a rhyme. It's a monoid.
gollark: How awful.
gollark: Antarcticr?

References
  1. ITU-T. "Recommendation X.736 : Information technology - Open Systems Interconnection - Systems Management: Security alarm reporting function". Retrieved 5 September 2019.
  2. ITU-T. "Recommendation X.733 : Informations technology - Open Systems Interconnection - Systems Management: Alarm reporting function".
  • (in English) RFC 4765, The Intrusion Detection Message Exchange Format (IDMEF)
  • (in English) RFC 4766, Intrusion Detection Message Exchange Requirements (IDMEF)
  • (in English) RFC 4767, The Intrusion Detection Exchange Protocol (IDXP)
  • (in English) Pravin Kothari, Intrusion Detection Interoperability and Standardization, SANS Institute InfoSec Reading Room, 19 février 2002
  • (in English) SECEF, Project for the promotion of the IDMEF and IODEF formats

Tutorials
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