Previous stories on KrebsOnSecurity about ATM skimming attacks have focused on innovative fraud devices made to attach to the outside of compromised ATMs. Security experts are now warning about the emergence of a new class of skimming scams aimed at draining ATM cash deposits via a novel and complex attack.
At issue is a form of ATM fraud known as a “black box” attack. In a black box assault, the crooks gain physical access to the top of the cash machine. From there, the attackers are able to disconnect the ATM’s cash dispenser from the “core” (the computer and brains of the device), and then connect their own computer that can be used to issue commands forcing the dispenser to spit out cash.
In this particular attack, the thieves included an additional step: They plugged into the controller a USB-based circuit board that NCR believes was designed to fool the ATM’s core into thinking it was still connected to the cash dispenser.