Screen: UTF-8 character handling vulnerability

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Gentoo Linux Security Advisory                          
GLSA 200611-01
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                                             http://security.gentoo.or
g/
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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-200
6-4573

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

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

   ht
tp://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
securitygentoo.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