A vulnerability in the TFTP request function of the Phone Proxy feature of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to pass traffic from an untrusted phone through the ASA.
The vulnerability is due to a limitation in processing the TFTP request for a configuration file. An attacker could exploit this vulnerability by sending a crafted TFTP request for a phone configuration file. An exploit could allow the attacker to pass traffic from an untrusted phone through the ASA.
Cisco has confirmed the vulnerability in a security notice; however, software updates are not available.
Cisco indicates through the CVSS score that proof-of-concept exploit code exists; however, the code is not known to be publicly available.