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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@xxxxxxxxxx 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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