[ GLSA 200409-04 ] Squid: Denial of service when using NTLM authentication

[GLSA]

Gentoo Linux Security Advisory

Title: Squid: Denial of service when using NTLM authentication (GLSA 200409-04)
Severity: normal
Exploitable: remote
Date: September 02, 2004
Updated: December 30, 2007
Bug(s): #61280
ID: 200409-04

Synopsis


Squid is vulnerable to a denial of service attack which could crash its
NTLM helpers.


Background


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.


Affected Packages

Package: net-proxy/squid
Vulnerable: <= 2.5.6-r1
Unaffected: >= 2.5.6-r2
Unaffected: < 2.5
Architectures: All supported architectures


Description


Squid 2.5.x versions contain a bug in the functions ntlm_fetch_string()
and ntlm_get_string() which lack checking the int32_t offset "o" for
negative values.


Impact


A remote attacker could cause a denial of service situation by sending
certain malformed NTLMSSP packets if NTLM authentication is enabled.


Workaround


Disable NTLM authentication by removing any "auth_param ntlm program
..." directives from squid.conf or use ntlm_auth from Samba-3.x.


Resolution


All Squid users should upgrade to the latest stable version: