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

From: Thierry Carrez (koon_at_gentoo.org)
Date: 09/02/04

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    To: gentoo-announce@lists.gentoo.org
Date: Thu, 02 Sep 2004 22:28:23 +0200

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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@gentoo.org 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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