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UNIRAS Brief - 713/06 - Gentoo Linux Security Advisory: GLSA 200611-01 - Screen: UTF-8 character handling vulnerability



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______________________________________________________________________________

 UNIRAS (UK Government CERT) Briefing - 713/06 dated 06.11.06 time 14:55
 UNIRAS is part of NISCC (the UK National Infrastructure Security
 Co-ordination Centre)
______________________________________________________________________________

 UNIRAS material is available from the NISCC website at www.niscc.gov.uk
______________________________________________________________________________

Title
=====

Gentoo Linux Security Advisory: GLSA 200611-01 - Screen: UTF-8 character handling 
vulnerability

Detail
======

cstone and Richard Felker discovered a flaw in Screen's UTF-8 combining
character handling.


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Gentoo Linux Security Advisory                           GLSA 200611-01
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                                             http://security.gentoo.org/
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   Severity: High
      Title: Screen: UTF-8 character handling vulnerability
       Date: November 03, 2006
       Bugs: #152770
         ID: 200611-01

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Synopsis
========

Screen contains an error in its UTF-8 character handling code that
would allow a remote Denial of Service or possibly the remote execution
of arbitrary code.

Background
==========

Screen is a full-screen window manager that multiplexes a physical
terminal between several processes, typically interactive shells.

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

     -------------------------------------------------------------------
      Package          /  Vulnerable  /                      Unaffected
     -------------------------------------------------------------------
   1  app-misc/screen       < 4.0.3                            >= 4.0.3

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

cstone and Richard Felker discovered a flaw in Screen's UTF-8 combining
character handling.

Impact
======

The vulnerability can be exploited by writing a special string of
characters to a Screen window. A remote attacker could cause a Denial
of Service or possibly execute arbitrary code with the privileges of
the user running Screen through a program being run inside a Screen
session, such as an IRC client or a mail client.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Screen users should upgrade to the latest version:

     # emerge --sync
     # emerge --ask --oneshot --verbose ">=app-misc/screen-4.0.3"

References
==========

   [ 1 ] CVE-2006-4573
         http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4573

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

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

   http://security.gentoo.org/glsa/glsa-200611-01.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@xxxxxxxxxx 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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______________________________________________________________________________

UNIRAS wishes to acknowledge the contributions of Gentoo for the
information contained in this briefing.
______________________________________________________________________________

This notice contains information released by the original author.
Some of the information may have changed since it was released. If the
vulnerability affects you, it may be prudent to retrieve the advisory
from the site of the original source to ensure that you receive the most
current information concerning that problem.

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<End of UNIRAS Briefing>

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