Genexis Platinum-4410 P4410-V2-1.31A - 'start_addr' Persistent Cross-Site Scripting

# Exploit Title: Genexis Platinum-4410 P4410-V2-1.31A - 'start_addr' Persistent Cross-Site Scripting
# Date: 03/25/2020
# Exploit Author: Jithin KS
# Vendor Homepage: https://www.gxgroup.eu/ont-products/
# Version: Platinum-4410 Software version - P4410-V2-1.31A
# Tested on: Windows 10
# Author Contact: hhttps://twitter.com/jithinks_8<https://twitter.com/amalmohandas0>

Vulnerability Details
======================
Genexis Platinum-4410 Home Gateway Unit is vulnerable to stored XSS in the "start_addr" parameter. This could allow attackers to perform malicious action in which the XSS popup will affect all privileged users.

How to reproduce
===================
1. Login to the firmware as any user
2. Navigate to Manage tab--> Security Management
3. Enter any valid value in Start Source Address and fill all other fields. Click Add.
4. Capture this request in Burp Suite. Enter payload <script>alert(1)</script> in "start_addr" text box and forward the request.
5. Relogin as any user and again navigate to Manage tab--> Security Management
6. Observe the XSS popup showing persistent XSS