Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Services Client-Side Request Smuggling Vulnerability

A vulnerability in the VPN web services component of Cisco Secure Firewall ASA and Threat Defense software allows an unauthenticated remote attacker to conduct browser-based attacks against users accessing VPN web portals. The vulnerability is caused by improper validation of HTTP requests in the web services component. An attacker can craft a malicious website that, when visited by an authenticated user, sends specially formed HTTP requests to the firewall. Because the requests are not properly validated, the firewall reflects the attacker's malicious input back to the user's browser, enabling cross-site scripting (XSS) and other browser-based attacks. The attacker cannot directly compromise the firewall itself, but can manipulate user sessions and capture sensitive information displayed in the browser.