Cisco Secure Access Control Server SSH Login Denial of Service Vulnerability

A vulnerability in the Secure Shell (SSH) feature of the Cisco Secure Access Control Server (ACS) could allow an authenticated, remote attacker to cause a partial denial of service (DoS) condition due to the SSH screen process unexpectedly terminating.

The vulnerability is due to improper input validation of user commands entered at the command line interface (CLI) or GUI. An attacker could exploit this vulnerability by logging into the affected device and executing crafted user commands. An exploit could allow the attacker to cause a partial DoS due to the SSH screen processes unexpectedly terminating. That SSH connection is then lost and the user must log in and authenticate again.

Cisco has confirmed the vulnerability; however, software updates are not available.

To exploit this vulnerability, an attacker must authenticate to the targeted device. This access requirement may reduce the likelihood of a successful exploit.

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