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Gentoo Linux Security Advisory GLSA 200507-20
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http://security.gentoo.org/
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Severity: Low
Title: Shorewall: Security policy bypass
Date: July 22, 2005
Bugs: #99398
ID: 200507-20

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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 *>= 2.2.5
>= 2.4.1

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.

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 (at) gentoo (dot) org [email concealed] 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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