If crooks find it too difficult to penetrate fraud-prevention layers protecting online merchants, corporations or bank accounts, they revert to “old-fashioned” fraud methods aimed at easier targets.

One of those “tried-and-true” scams involves simply calling the target, pretending to be someone else and coming up with a reason for the victim to send money, says Julie Conroy McNelley, senior analyst and fraud expert with Boston-based Aite Group.