Trustwave SpiderLabs security researcher Jonathan Claudius has discovered a privilege escalation vulnerability in Cisco ASA's SSL VPN service. Cisco ASA is one of the most popular and widely deployed firewalls in the world. Like most firewalls it provides a variety of features including a client-to-site SSL VPN. This vulnerability allows any user with an established VPN to gain full administrative access to the ASA device.
The vulnerability exists in the SSL VPN web portal. After connecting to the VPN any user can craft a specific URL to execute arbitrary commands on the ASA system. This would initially allow the user to elevate their privilege on the device by creating an administrative account. In turn, the administrative account could be used for full access to the ASA appliance.