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

http://security.gentoo.org/

Severity:	normal
Title:	Squid: Denial of service when using NTLM authentication
Date:	09/02/2004
Bugs:	#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	Vulnerable	Unaffected	Architecture(s)
net-proxy/squid	<= 2.5.6-r1	>= 2.5.6-r2	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:

    # emerge sync
    
    # emerge -pv ">=net-www/squid-2.5.6-r2"
    # emerge ">=net-www/squid-2.5.6-r2"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200409-04.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.