[c-nsp] Cisco Security Advisory: Cisco ASA Clientless SSL VPN CIFS Heap Overflow Vulnerability

Wed Feb 8 11:08:47 EST 2017

A vulnerability in Common Internet Filesystem (CIFS) code in the Clientless SSL VPN functionality of Cisco ASA Software could allow an authenticated, remote attacker to cause a heap overflow.

The vulnerability is due to insufficient validation of user supplied input. An attacker could exploit this vulnerability by sending a crafted URL to the affected system. An exploit could allow the remote attacker to cause a reload of the affected system or potentially execute code.

Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 or IPv6 traffic. A valid TCP connection is needed to perform the attack. The attacker needs to have valid credentials to log in to the Clientless SSL VPN portal.

Cisco has released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are available. This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170208-asa