Flatnuke3 Remote Cookie Manipoulation / Privilege Escalation

[kingoftheworld92 () fastwebnet it]

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

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Flatnuke3 Remote Cookie Manipoulation / Privilege Escalation

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#By KiNgOfThEwOrLd

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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
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