How can Cross-Site Request Forgery (CSRF) be effectively prevented?

Implementing anti-CSRF tokens and validating requests is a robust and effective strategy for preventing Cross-Site Request Forgery (CSRF) attacks. CSRF occurs when an attacker tricks a user’s browser into making unwanted requests to a different site where the user is authenticated, such as a banking site.

Anti-CSRF tokens work by generating a unique, unpredictable token for each user session or request, which must be included with any sensitive operations (such as form submissions) that change the state on the server. When the server receives a request, it checks for the presence of this token and verifies its validity before processing the request. This means that even if an attacker manages to generate a forged request, they cannot include a valid token, and the server will reject the request.

This method effectively ensures that every state-changing request is made deliberately by the authenticated user, thereby safeguarding against unauthorized actions that could be initiated through a CSRF attack.