[ GLSA 200907-13 ] PulseAudio: Local privilege escalation

[Robert Buchholz <rbu () gentoo org>]

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Gentoo Linux Security Advisory                           GLSA 200907-13
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                                            http://security.gentoo.org/
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  Severity: High
     Title: PulseAudio: Local privilege escalation
      Date: July 16, 2009
      Bugs: #276986
        ID: 200907-13

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Synopsis
========

A vulnerability in PulseAudio may allow a local user to execute code
with escalated privileges.

Background
==========

PulseAudio is a network-enabled sound server with an advanced plug-in
system.

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

    -------------------------------------------------------------------
     Package                 /   Vulnerable   /             Unaffected
    -------------------------------------------------------------------
  1  media-sound/pulseaudio      < 0.9.9-r54              >= 0.9.9-r54

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

Tavis Ormandy and Julien Tinnes of the Google Security Team discovered
that the pulseaudio binary is installed setuid root, and does not drop
privileges before re-executing itself. The vulnerability has
independently been reported to oCERT by Yorick Koster.

Impact
======

A local user who has write access to any directory on the file system
containing /usr/bin can exploit this vulnerability using a race
condition to execute arbitrary code with root privileges.

Workaround
==========

Ensure that the file system holding /usr/bin does not contain
directories that are writable for unprivileged users.

Resolution
==========

All PulseAudio users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot -v ">=media-sound/pulseaudio-0.9.9-r54"

References
==========

  [ 1 ] CVE-2009-1894
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1894

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

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

  http://security.gentoo.org/glsa/glsa-200907-13.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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