isakmpd crashes when handling ISAKMP packets with malformed "Delete Payload"

ID VU:524497
Type cert
Reporter CERT
Modified 2004-08-27T13:26:00



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 Delete Payload contains a protocol-specific security association identifier that the sender has removed from its security association database and is, therefore, no longer valid. [...] It is possible to send multiple Security Parameter Index(es) (SPIs) in a Delete payload [...]

To this end, the format of the "Delete Payload" contains a "# of SPIs" field, specified as two octets. A flaw exists in the way that isakmpd handles malformed ISAKMP packets specifying an overly large number of SPIs for deletion. 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


Filter by status: All Affected Not Affected Unknown

Filter by content: __ Additional information available

__ Sort by: Status Alphabetical

Expand all

Javascript is disabled. Click here to view vendors.

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.

CVSS Metrics

Group | Score | Vector
Base | |
Temporal | |
Environmental | |



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-2004-0221
Severity Metric: | 1.69
Date Public: | 2004-03-19
Date First Published: | 2004-08-27
Date Last Updated: | 2004-08-27 13:26 UTC
Document Revision: | 11