phpBB: Remote command execution — GLSA 200411-32

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

Affected packages

Package	www-apps/phpbb on all architectures
Affected versions	< 2.0.10
Unaffected versions	>= 2.0.11

Background

phpBB is an Open Source bulletin board package.

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

Release date
November 24, 2004

Latest revision
May 22, 2006: 02

Severity
high

Exploitable
remote

Bugzilla entries

71681