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                                    CERT-Renater

                         Note d'Information No. 2006/VULN434
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DATE                      : 04/08/2006

HARDWARE PLATFORM(S)      : /

OPERATING SYSTEM(S)       : Systems running LibVNCServer.

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Gentoo Linux Security Advisory                           GLSA 200608-05
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                                             http://security.gentoo.org/
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   Severity: High
      Title: LibVNCServer: Authentication bypass
       Date: August 04, 2006
       Bugs: #136916
         ID: 200608-05

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Synopsis
========

VNC servers created with LibVNCServer accept insecure protocol types,
even when the server does not offer it, resulting in unauthorized
access to the server.

Background
==========

LibVNCServer is a GPL'ed library for creating VNC servers.

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

     -------------------------------------------------------------------
      Package                /  Vulnerable  /                Unaffected
     -------------------------------------------------------------------
   1  net-libs/libvncserver       < 0.8.2                      >= 0.8.2

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

LibVNCServer fails to properly validate protocol types effectively
letting users decide what protocol to use, such as "Type 1 - None".
LibVNCServer will accept this security type, even if it is not offered
by the server.

Impact
======

An attacker could use this vulnerability to gain unauthorized access
with the privileges of the user running the VNC server.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All LibVNCServer users should upgrade to the latest version:

     # emerge --sync
     # emerge --ask --oneshot --verbose ">=net-libs/libvncserver-0.8.2"

References
==========

   [ 1 ] CVE-2006-2450
         http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2450

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

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

   http://security.gentoo.org/glsa/glsa-200608-05.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.org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2006 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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