Referer-based access control

Description

This lab controls access to certain admin functionality based on the Referer header. You can familiarise yourself with the admin panel by logging in using the credentials administrator:admin.

Reproduction and proof of concept

1. Log in using the admin credentials administrator:admin.

2. Browse to the admin panel, promote carlos, and send the HTTP request to Burp Repeater.

3. Open a private/incognito browser window, and log in with the non-admin credentials.

4. Browse to /admin-roles?username=carlos&action=upgrade and observe that the request is treated as unauthorised due to the absent Referer header.

5. Copy the non-admin user’s session cookie into the existing Burp Repeater request, change the username to yours, and replay it.

Exploitability

An attacker will need to log in using the credentials wiener:peter and exploit the flawed access controls to become an administrator.