Cisco StarOS SSH Privilege Escalation Vulnerability

A privilege escalation vulnerability in the Secure Shell (SSH) subsystem in the StarOS operating system for Cisco ASR 5000 Series, ASR 5500 Series, ASR 5700 Series devices, and Cisco Virtualized Packet Core could allow an authenticated, remote attacker to gain unrestricted, root shell access.

The vulnerability is due to missing input validation of parameters passed during SSH or SFTP login. An attacker could exploit this vulnerability by providing crafted user input to the SSH or SFTP command-line interface (CLI) during SSH or SFTP login. An exploit could allow an authenticated attacker to gain root privileges access on the router.

Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered via both IPv4 and IPv6 traffic. An established TCP connection toward port 22, the SSH default port, is needed to perform the attack. The attacker must have valid credentials to login to the system via SSH or SFTP.

Cisco has released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are not available.

This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170315-asr [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170315-asr”]