Flatnuke3 Remote Cookie Manipoulation / Privilege Escalation

---------------------------------------------------------------
 ____            __________         __             ____  __   
/_   | ____     |__\_____  \  _____/  |_          /_   |/  |_ 
 |   |/    \    |  | _(__  <_/ ___\   __\  ______  |   \   __\
 |   |   |  \   |  |/       \  \___|  |   /_____/  |   ||  |  
 |___|___|  /\__|  /______  /\___  >__|            |___||__|  
          \/\______|      \/     \/                         
---------------------------------------------------------------

Http://www.inj3ct-it.org             Staff[at]inj3ct-it[dot]org 

---------------------------------------------------------------

Flatnuke3 Remote Cookie Manipoulation / Privilege Escalation

---------------------------------------------------------------

#By KiNgOfThEwOrLd

---------------------------------------------------------------
PoC:

When an user log in, flatnuke set him a cookie value like this: 
myforum=nomeuser. If we try to change it, flatnuke will ask us to log in again. 
The code is:

$req = $_SERVER["REQUEST_URI"];
if (strstr($req, "myforum="))
die(_NONPUOI);

So, we can bypass this filter, using nullbyte and login as admin. For example, 
Replace: 

myforum=yourusername 

with: 

myforum%00=adminusername

PHP Execution PoC:

I saw that in download module, if we set to "1" the fneditmode, we can make 
directory. So, we can write a description for the directory, and this 
description will be saved in /Download/[Dir_Name]/description.it.php . Yes, we 
can insert php code in the description and it will be execute! Nice, dontcha? :P
---------------------------------------------------------------