Flatnuke3 Remote Cookie Manipoulation / Privilege Escalation

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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