Cross-Site Request Forgery (CSRF) are request to the server initiated from other websites. Allowing this is potentially dangerous as the request piggybacks on the existing session on the server if it's ran from the same browser (imagine 2 tabs, 1 logged in on the server, the other with a malicious site that sends a request to the server).  The most suitable way to prevent this seems to be Synchronizer Token Pattern  (STP) which effectively requires a unique token to be sent...