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Gentoo Linux Security Advisory                           GLSA 200503-02
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: phpBB: Multiple vulnerabilities
      Date: March 01, 2005
      Bugs: #82955
        ID: 200503-02

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Synopsis
========

Several vulnerabilities allow remote attackers to gain phpBB
administrator rights or expose and manipulate sensitive data.

Background
==========

phpBB is an Open Source bulletin board package.

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

    -------------------------------------------------------------------
     Package         /  Vulnerable  /                       Unaffected
    -------------------------------------------------------------------
  1  www-apps/phpBB      < 2.0.13                            >= 2.0.13

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

It was discovered that phpBB contains a flaw in the session handling
code and a path disclosure bug. AnthraX101 discovered that phpBB allows
local users to read arbitrary files, if the "Enable remote avatars" and
"Enable avatar uploading" options are set (CAN-2005-0259). He also
found out that incorrect input validation in "usercp_avatar.php" and
"usercp_register.php" makes phpBB vulnerable to directory traversal
attacks, if the "Gallery avatars" setting is enabled (CAN-2005-0258).

Impact
======

Remote attackers can exploit the session handling flaw to gain phpBB
administrator rights. By providing a local and a remote location for an
avatar and setting the "Upload Avatar from a URL:" field to point to
the target file, a malicious local user can read arbitrary local files.
By inserting "/../" sequences into the "avatarselect" parameter, a
remote attacker can exploit the directory traversal vulnerability to
delete arbitrary files. A flaw in the "viewtopic.php" script can be
exploited to expose the full path of PHP scripts.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All phpBB users should upgrade to the latest available version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=www-apps/phpBB-2.0.13"

References
==========

  [ 1 ] CAN-2005-0258
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0258
  [ 2 ] CAN-2005-0259
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0259
  [ 3 ] phpBB announcement
        http://www.phpbb.com/phpBB/viewtopic.php?f=14&t=267563

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

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

  http://security.gentoo.org/glsa/glsa-200503-02.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 2005 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