Squid: NTLM authentication helper buffer overflow

Background

Squid contains a bug in the function ntlm_check_auth(). It fails to do proper bounds checking on the values copyied to the ‘pass’ variable.

Description

Squid is a full-featured Web Proxy Cache designed to run on Unix systems. It supports proxying and caching of HTTP, FTP, and other URLs, as well as SSL support, cache hierarchies, transparent caching, access control lists and many other features.

Impact

If Squid is configured to use NTLM authentication, an attacker could exploit this vulnerability by sending a very long password. This could lead to arbitrary code execution with the permissions of the user running Squid.

Workaround

There is no known workaround at this time. All users are encouraged to upgrade to the latest available version.

Resolution

All Squid users should upgrade to the latest stable version:

 # emerge sync

 # emerge -pv ">=net-proxy/squid-2.5.5-r2"
 # emerge ">=net-proxy/squid-2.5.5-r2"