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Gentoo Linux Security Advisory                           GLSA 200608-12
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                                            https://security.gentoo.org/
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  Severity: High
     Title: x11vnc: Authentication bypass in included LibVNCServer code
      Date: August 07, 2006
      Bugs: #142559
        ID: 200608-12

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Synopsis
=======
VNC servers created with x11vnc accept insecure protocol types, even
when the server does not offer it, resulting in the possibility of
unauthorized access to the server.

Background
=========
x11vnc provides VNC servers for X displays.

Affected packages
================
    -------------------------------------------------------------------
     Package          /  Vulnerable  /                      Unaffected
    -------------------------------------------------------------------
  1  x11-misc/x11vnc       < 0.8.1                            >= 0.8.1

Description
==========
x11vnc includes vulnerable LibVNCServer code, which fails to properly
validate protocol types effectively letting users decide what protocol
to use, such as "Type 1 - None" (GLSA-200608-05). x11vnc will accept
this security type, even if it is not offered by the server.

Impact
=====
An attacker could exploit 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 x11vnc users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=x11-misc/x11vnc-0.8.1"

References
=========
  [ 1 ] CVE-2006-2450
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2450
  [ 2 ] GLSA-200608-05
        https://security.gentoo.org/glsa/200608-05

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

  https://security.gentoo.org/glsa/200608-12

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
https://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.

https://creativecommons.org/licenses/by-sa/2.5/