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Gentoo Linux Security Advisory                           GLSA 200411-32
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                                            http://security.gentoo.org/
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  Severity: High
     Title: phpBB: Remote command execution
      Date: November 24, 2004
      Bugs: #71681
        ID: 200411-32

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Synopsis
========

phpBB contains a vulnerability which allows a remote attacker to
execute arbitrary commands with the rights of the web server user.

Background
==========

phpBB is an Open Source bulletin board package.

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

    -------------------------------------------------------------------
     Package         /  Vulnerable  /                       Unaffected
    -------------------------------------------------------------------
  1  www-apps/phpbb      < 2.0.10                            >= 2.0.11

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

phpBB contains a vulnerability in the highlighting code and several
vulnerabilities in the username handling code.

Impact
======

An attacker can exploit the highlighting vulnerability to access the
PHP exec() function without restriction, allowing them to run arbitrary
commands with the rights of the web server user (for example the apache
user). Furthermore, the username handling vulnerability might be abused
to execute SQL statements on the phpBB database.

Workaround
==========

There is a one-line patch which will remediate the remote execution
vulnerability.

Locate the following block of code in viewtopic.php:

    //
    // Was a highlight request part of the URI?
    //
    $highlight_match = $highlight = '';
    if (isset($HTTP_GET_VARS['highlight']))
    {
       // Split words and phrases
       $words = explode(' ', 
trim(htmlspecialchars(urldecode($HTTP_GET_VARS['highlight']))));
    
       for($i = 0; $i < sizeof($words); $i++)
       {

Replace with the following:

    //
    // Was a highlight request part of the URI?
    //
    $highlight_match = $highlight = '';
    if (isset($HTTP_GET_VARS['highlight']))
    {
       // Split words and phrases
       $words = explode(' ', 
trim(htmlspecialchars($HTTP_GET_VARS['highlight'])));
    
       for($i = 0; $i < sizeof($words); $i++)
       {

Resolution
==========

All phpBB users should upgrade to the latest version to fix all known
vulnerabilities:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=www-apps/phpbb-2.0.11"

References
==========

  [ 1 ] phpBB.com Announcement
        http://www.phpbb.com/phpBB/viewtopic.php?t=240513

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

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

  http://security.gentoo.org/glsa/glsa-200411-32.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 2004 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/2.0