Device, system, and method of differentiating over multiple accounts between legitimate user and cyber-attacker

Abstract

Devices, systems, and methods of user authentication, as well as automatic differentiation between a legitimate user and a cyber-attacker. A system detects that two different accounts of the same computerized service, were accessed by a single computing device over a short period of time. The system may employ various techniques in order to determine automatically whether a legitimate user accessed the two different account, such as, a husband accessing his own bank account and shortly after that accessing also his wife's bank account, or a payroll company accessing bank accounts of two clients for payroll management purposes. Conversely, the system is able to detect that the same user exhibited the same pattern of interactions when operating the two accounts, a pattern of interactions that does not frequently appear in the general population of legitimate users, thereby indicating that the single user is a cyber-attacker.