A serious vulnerability has been found in the authentication process of the popular network LinkedIN. The attack is possible due to an error in validating of the security token (CSRF token) that allows to the attacker to send an unlimited number of requests using the same token for different users. The only secure mechanism implemented against the attack is a Captcha challenge-response test after a dozens of attempts. Any vulnerability in this type of systems exposes users to risks of identity theft, a hacker could collect information about the victim using its profile for other purposes.”]