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isakmpd crashes when handling ISAKMP packets with malformed "Security Association Payload"

Vulnerability Note VU#785945

Original Release Date: 2004-08-27 | Last Revised: 2004-08-27


A vulnerability exists in the isakmpd that could allow a remote attacker to cause a denial of service.


The OpenBSD isakmpd establishes security associations for encrypted and authenticated (IPsec) network traffic. It implements the Internet Security Association and Key Management Protocol (ISAKMP) and Internet Key Exchange (IKE) protocol. The ISAKMP standard specifies:

The Security Association Payload is used to negotiate security attributes and to indicate the Domain of Interpretation (DOI) and Situation under which the negotiation is taking place.

A flaw exists in the way that isakmpd handles ISAKMP packets containing a malformed "Security Association Payload". Such malformed packets could cause isakmpd to read out of bounds and crash.


A remote attacker could cause the isakmpd service to crash. Subsequent IPsec-enabled communications may be disrupted as a result.


Apply a patch from the vendor

Patches have been released to address this issue. Please see the Systems Affected section of this document for more details.

Vendor Information


OpenBSD Affected

Updated:  August 20, 2004



Vendor Statement

Several bugs have been found in the ISAKMP daemon which can lead to memory
leaks and a remote denial of service condition. An attacker can craft
malformed payloads that can cause the isakmpd(8) process to stop
processing requests.

The problem is fixed in -current, 3.4-stable and 3.3-stable.

Patches are available at:

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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This vulnerability was discovered by Rapid7 using their Striker test suite.

This document was written by Chad R Dougherty based on information published in Rapid7 Advisory R7-0018.

Other Information

CVE IDs: CVE-2004-0219
Severity Metric: 1.69
Date Public: 2004-03-19
Date First Published: 2004-08-27
Date Last Updated: 2004-08-27 13:28 UTC
Document Revision: 9

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