Vulnerability Alert

Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.

The vulnerability is due to improper handling of malformed H.323 packets by the affected software.  An unauthenticated, remote attacker could exploit this vulnerability by sending malformed H.323 packets to a targeted device.  If successful, the attacker could cause the device to reload or trigger memory leaks that may result in system instabilities, resulting in a DoS condition.

Cisco has confirmed the vulnerability in a security advisory and released software updates.

Cisco has published a list of affected Cisco IOS Software releases in the security advisory.  The Vendor Announcements section of this alert contains a link to the advisory.

To exploit the vulnerability, the attacker may provide a multimedia file to the user and persuade the user to open or execute the file by using misleading language or instructions.  Opening the file may result in the processing of malformed H.323 packets by the affected software.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.

Cisco has released a security advisory for Cisco bug ID CSCtq45553 at the following link: cisco-sa-20120328-zbfw