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Apple iChat fails to properly handle crafted TXT key hashes

Vulnerability Note VU#836024

Original Release Date: 2007-02-26 | Last Revised: 2007-03-16


A vulnerability in the way Apple iChat handles specially crafted TXT key hashes could lead to denial of service.


Apple iChat is an instant message client for Apple Mac OS X. Apple iChat Agent is a back-end process that manages iChat sessions and available contacts. Apple Bounjour is a service provided with Apple Mac OS X that facilitates automatic discovery of computers, devices, and services on IP networks. The iChat Agent uses Bonjour to discover available contacts. The Apple iChat Agent contains a vulnerability that could be exploited when it attempts to handle specially crafted TXT key hashes received via Bonjour messages. According to MOAB-29-01-2007:

This will instantly cause a SIGTRAP signal to be sent to the process, causing a so-called 'crash'. Further attempts to launch iChat Bonjour functionality again will fail as mDNSResponder keeps the crafted record (and restarting it will be necessary).


A remote, unauthenticated attacker on the same multicast network may be able to cause iChat to crash, thereby creating a denial-of-service condition.



Apple has released an update to address this issue. See Apple Security Update 2007-002.

Vendor Information


Apple Computer, Inc. Affected

Updated:  February 16, 2007



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

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


Refer to Apple Security Update 2007-002.

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

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This issue was reported by LMH in MOAB-29-01-2007.

This document was written by Chris Taschner.

Other Information

CVE IDs: CVE-2007-0710
Severity Metric: 2.48
Date Public: 2007-01-30
Date First Published: 2007-02-26
Date Last Updated: 2007-03-16 12:36 UTC
Document Revision: 23

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