System for automated prevention of fraud

A system for preventing fraud of a web service offered by a service provider (500) at a website, which comprises:

• a fake credential distributor (100) for automatic creating a set of valid but fake credentials to access such website of the service provider and for distributing such set of fake credentials to a plurality of predefined websites;
• a fake user database (400) including at least said set of fake credentials;
• a real-time monitor (300) connected between any possible user connection (10, 10′) to such webpage and the service provider (500) for real-time monitoring any user login attempt from any origin network location to the website, and for comparing the credentials used in such user login attempt with the set of fake credentials in the fake user database (400), and
• if the credentials used in such user login attempt coincide with any fake credential in the fake user database (400), such origin network location is added to an internal list of tainted connections;
• and
• if there is any other login attempt of a user from an origin network location in said list of tainted connections, said user access request is refused, even when it is using real credentials and such user is redirected to a pre-established webpage not enabling such user to access the web service.