Lab: Host validation bypass via connection state attack

Solving this lab requires features first released in Burp Suite 2022.8.1.

1. Send the GET / request to Burp Repeater.

2. Make the following adjustments:

   • Change the path to /admin.

   • Change Host header to 192.168.0.1.

3. Send the request. Observe that you are simply redirected to the homepage.

4. Duplicate the tab, then add both tabs to a new group.

5. Select the first tab and make the following adjustments:

   • Change the path back to /.

   • Change the Host header back to YOUR-LAB-ID.h1-web-security-academy.net.

6. Using the drop-down menu next to the Send button, change the send mode to Send group in sequence (single connection).

7. Change the Connection header to keep-alive.

8. Send the sequence and check the responses. Observe that the second request has successfully accessed the admin panel.

9. Study the response and observe that the admin panel contains an HTML form for deleting a given user. Make a note of the following details:

   • The action attribute (/admin/delete)

   • The name of the input (username)

   • The csrf token.

10. On the second tab in your group, use these details to replicate the request that would be issued when submitting the form. The result should look something like this:

    POST /admin/delete HTTP/1.1 Host: 192.168.0.1 Cookie: _lab=YOUR-LAB-COOKIE; session=YOUR-SESSION-COOKIE Content-Type: x-www-form-urlencoded Content-Length: CORRECT csrf=YOUR-CSRF-TOKEN&username=carlos

11. Send the requests in sequence down a single connection to solve the lab.