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ERRATA: [ GLSA 200507-20 ] Shorewall: Security policy bypass
From: Thierry Carrez <koon () gentoo org>
Date: Sat, 17 Sep 2005 14:31:52 +0200

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Gentoo Linux Security Advisory [ERRATA UPDATE]        GLSA 200507-20:02
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: Shorewall: Security policy bypass
      Date: July 22, 2005
   Updated: September 14, 2005
      Bugs: #99398
        ID: 200507-20:02

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Errata
======

The "unaffected" version was incorrectly set to 2.4.1 in the initial
advisory, the correct "unaffected" version is 2.4.2.

The corrected sections appear below.

Synopsis
========

A vulnerability in Shorewall allows clients authenticated by MAC
address filtering to bypass all other security rules.

Background
==========

Shorewall is a high level tool for configuring Netfilter, the firewall
facility included in the Linux Kernel.

Affected packages
=================

    -------------------------------------------------------------------
     Package                 /  Vulnerable  /               Unaffected
    -------------------------------------------------------------------
  1  net-firewall/shorewall      <= 2.4.1                     >= 2.4.2

Description
===========

Shorewall fails to enforce security policies if configured with
"MACLIST_DISPOSITION" set to "ACCEPT" or "MACLIST_TTL" set to a value
greater or equal to 0.

Impact
======

A client authenticated by MAC address filtering could bypass all
security policies, possibly allowing him to gain access to restricted
services. The default installation has MACLIST_DISPOSITION=REJECT and
MACLIST_TTL=(blank) (equivalent to 0). This can be checked by looking
at the settings in /etc/shorewall/shorewall.conf

Workaround
==========

Set "MACLIST_TTL" to "0" and "MACLIST_DISPOSITION" to "REJECT" in the
Shorewall configuration file (usually /etc/shorewall/shorewall.conf).

Resolution
==========

All Shorewall users should upgrade to the latest available version:

    # emerge --sync
    # emerge --ask --oneshot --verbose net-firewall/shorewall

References
==========

  [ 1 ] CAN-2005-2317
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2317
  [ 2 ] Shorewall Announcement
        http://www.shorewall.net/News.htm#20050717

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200507-20.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 2005 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/2.0

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