Pound: HTTP request smuggling

Background

Pound is a reverse proxy, load balancer and HTTPS front-end. It allows to distribute the load on several web servers and offers a SSL wrapper for web servers that do not support SSL directly.

Description

Pound fails to handle HTTP requests with conflicting “Content-Length” and “Transfer-Encoding” headers correctly.

Impact

An attacker could exploit this vulnerability by sending HTTP requests with specially crafted “Content-Length” and “Transfer-Encoding” headers to bypass certain security restrictions or to poison the web proxy cache.

Workaround

There is no known workaround at this time.

Resolution

All Pound users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose www-servers/pound