Vulnerability Note VU#524497

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

Overview

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

I. Description

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security association identifier that the sender has removed from its security association database and is, therefore, no longer valid.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.

II. Impact

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

III. Solution

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.

Systems Affected

Vendor	Status	Date Notified	Date Updated
OpenBSD	Vulnerable	20-Aug-2004

References

Credit

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

Date Public:	2004-03-19
Date First Published:	2004-08-27
Date Last Updated:	2004-08-27
CERT Advisory:
CVE-ID(s):	CAN-2004-0221
NVD-ID(s):	CAN-2004-0221
US-CERT Technical Alerts:
Metric:	1.69
Document Revision:	10

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