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



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Gentoo Linux Security Advisory                           GLSA 200409-04
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: Squid: Denial of service when using NTLM authentication
      Date: September 02, 2004
      Bugs: #61280
        ID: 200409-04

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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
    -------------------------------------------------------------------
  1  www-proxy/squid      <= 2.5.6-r1                      >= 2.5.6-r2
                                                                 < 2.5

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
==========

  [ 1 ] Squid-2.5 Patches

http://www1.uk.squid-cache.org/squid/Versions/v2/2.5/bugs/#squid-2.5.STABLE6-ntlm_fetch_string

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@xxxxxxxxxx or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/1.0

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