to Conduct HTTP Response Smuggling Attacks

A potential vulnerability was reported in Microsoft Internet Information Server (IIS) when used in conjunction with certain gateway and proxy servers. A remote user can conduct HTTP request smuggling attacks.

If the web server is used in conjunction with a proxy server or application gateway (e.g., cache, firewall) and if there is an input validation vulnerability in the web server or one of its applications, then a remote user can use HTTP request smuggling techniques to hijack a target user's request or conduct a variation of a cross-site scripting attack against a target user.

A remote user can send multiple, HTTP requests with specially crafted HTTP headers to the target server via the proxy/gateway server. The requests may be interpreted differently by the target server than by the proxy/gateway server. As a result, unexpected results may occur. A remote user may be able to poison an intermediate cache, bypass application-level security features within an intermediate proxy/gateway server, or conduct cross-site scripting attacks against target users.

Networks that use IIS in conjunction with Squid, Apache, Internet Security and Acceleration Server, DeleGate, or FireWall-1 may be affected. Other configurations may also be affected.

This vulnerability was reported by Watchfire.

A description of HTTP request smuggling attacks is available at:

http://www.watchfire.com/resources/HTTP-Request-Smuggling. pdf

Impact: Depending on the associated proxy/gateway server used in conjunction with the target system, a remote user may be able to poison an intermediate cache, bypass application-level security features within an intermediate proxy/gateway server, or conduct cross-site scripting attacks against target users.

Solution: No solution was available at the time of this entry.
Cause: State error
Underlying OS: Windows (Any)

http://securitytracker.com/alerts/2005/Jul/1014364.html