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Gentoo Linux Security Advisory                           GLSA 200904-10
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: Avahi: Denial of Service
      Date: April 08, 2009
      Bugs: #260971
        ID: 200904-10

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Synopsis
========

An error in Avahi might lead to a Denial of Service via network and CPU
consumption.

Background
==========

Avahi is a system that facilitates service discovery on a local
network.

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

    -------------------------------------------------------------------
     Package        /   Vulnerable   /                      Unaffected
    -------------------------------------------------------------------
  1  net-dns/avahi      < 0.6.24-r2                       >= 0.6.24-r2

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

Rob Leslie reported that the
originates_from_local_legacy_unicast_socket() function in
avahi-core/server.c does not account for the network byte order of a
port number when processing incoming multicast packets, leading to a
multicast packet storm.

Impact
======

A remote attacker could send specially crafted legacy unicast mDNS
query packets to the Avahi daemon, resulting in a Denial of Service due
to network bandwidth and CPU consumption.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Avahi users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-dns/avahi-0.6.24-r2"

References
==========

  [ 1 ] CVE-2009-0758
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0758

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

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

  http://security.gentoo.org/glsa/glsa-200904-10.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 2009 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/2.5