File: go-pear.php
Affects: v0.2.2 (May affect other versions)
Date: 6th January 2006

Issue Description:

A vulnerability exists within version 0.2.2 of go-pear.php, part of PHP's PEAR Package.
The problem lies in the scripts capacity to utilize a proxy server.

An attacker can take advantage of this option by providing it with a malicious proxy server
that is configured to redirect the original request to another file server.
By simply mirroring the requested content from the intended file server
the attacker can assure the script continues running uninterrupted.

Hosting a modified version of "Tar.php" and pre pending code to the extractModify() function
will allow the attacker to run any PHP code of their choosing. This occurs because go-pear uses
"Tar.php" to extract all the packages it previously retrieved, in doing so it invokes the now
compromised version of extractModify().

Scope:

This vulnerability has the most serious implications for Apache2Triad users
as the go-pear.php script is installed by default and is accessible at

http://www.yoursite.com/php/pear/go-pear.php

Recommendation:

Regular PEAR users should simply update to the latest version available
at http://pear.php.net

Apache2Triad users who simply wish to address this issue should do the following:

[1] Go to your apache2triad directory
[2] Navigate to \php\pear
[3] Rename or delete the "go-pear.php" file

Discovered By: Gammarays