[ GLSA 200904-10 ] Avahi: Denial of Service

[Robert Buchholz <rbu () gentoo org>]

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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

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