rambabu-posa / play-scala-csrf

Demonstration of CSRF issue in Play Framework 2.5.0

Demonstration of CSRF issue

This project is only here to demonstrate a potential issue with the CSRF check in Play Framework 2.5.0.

Manual testing in browser

• Start application: sbt run
• Navigate to http://localhost:9000/form/notoken. This will not add a CSRF token to the session. Make sure there are no cookies present in the browser added by previous apps that ran on localhost.
• Submit the form via a POST request by clicking the Submit button.
• Due to the missing CSRF token you should get an error response, but you will see a success message.
• Now navigate to http://localhost:9000/form/addtoken. This will add a CSRF token to the session and the form. (The CSRF token in the form has been put into an input type="text" field for easier manipulation. Usually this would be an input type="hidden" field.)
• Submit the form via a POST request by clicking the Submit button.
• You will correctly see a success message, because the CSRF tokens in the session cookie matched the token in the form.
• Go back to http://localhost:9000/form/addtoken (reload the page).
• Remove or manipulate the CSRF token in the input field and submit the form again.
• You will see the request is correctly rejected, because tokens in session and form did not match.
• Go back to http://localhost:9000/form/addtoken (reload the page).
• Delete all cookies for the localhost domain in your browser, e.g. using Google Chrome's inspector, select tab Resources, select Cookies, select localhost, select the cookie PLAY_SESSION (and any other cookies that might be there).
• Put anything you want into the input field of the form.
• Submit the form via a POST request by clicking the Submit button.
• Due to the missing CSRF token you should get an error response, but you will see a success message.

Manual testing with Curl

Run the application

sbt run

Then post a request to the protected route, which should give you an error response, but doesn't:

curl -X POST http://localhost:9000/form/check

Or post a request to the protected route with any cookie, which will produce an error response:

curl -X POST --cookie "SOME_COOKIE=abc" http://localhost:9000/form/check

Automated tests

I've added tests for all this in test/CsrfSpec.scala.

Start sbt and run test-only CsrfSpec. Three of the tests will fail; whenever there is no cookie in the header of the POST request to the protected route, the action is executed.