Ever since the first ATMs were installed in the United States more than 40 years ago, criminals have used a variety of methods to steal money, through either physical or virtual attacks on machines or customers. The early ATMs were installed primarily through the exterior wall of bank branches, so they were generally as secure as the building's cash vault. Consequently, the attacks generally took the form of robbing customers using or employees servicing an ATM.

The industry reacted, with some state regulatory nudging, with camera surveillance, improved lighting and visibility, privacy screens, drive-up reconfigurations, and customer safety education programs. When less-armored, freestanding cash dispensers began to appear in retail locations, criminals turned to trying to pull the entire ATM out from its floor or wall anchors and then cracking it open at a remote location.

As criminals grew more sophisticated, they turned their attention from such aggressive physical attacks to stealthier ones. In one such activity, referred to as "skimming," they place false card readers over the real ones to capture the data on the cards' magnetic stripe so they can create a counterfeit card. The criminals may generally also install a pinhole camera positioned to capture the customers entering their PINs on the keypad. Card skimming has become a major problem for the card payments industry overall and has been an impetus for the migration to chip cards throughout the world and finally in the U.S.

Some recent efforts to attack ATMs have involved gaining unauthorized access to the applications controlling ATM transaction authorizations. In an incident in Oman that took place earlier this year, cyberthieves established real-time access to the authorization files on a foreign bank's prepaid card application system and changed the balance available for withdrawals. They also continually reset the daily usage counters. Using a large gang of money mules with counterfeit cards and the PIN to access the prepaid account, the criminals conducted a coordinated attack, making continuous cash withdrawals at numerous foreign ATMs until the cash supply at all the ATMs was exhausted. This gang netted the equivalent of almost US$39 million—yes, that's not a typo, it was $39 million.

It now appears there is a trend, at least in Europe, of criminals resorting to physical attacks on the ATMs again. Gangs have been injecting explosive liquids and gases into ATMs, then igniting them to blast open the ATM vault to gain access to the currency cassettes. I believe it is only a matter of time before such attacks are initiated here in the United States.

These activities emphasize that criminal attacks against our payments system will continue to take different forms and target all payment channels. In a comprehensive risk management plan, stakeholders must always anticipate the next type of attack and take the necessary and prudent preventive measures. Sometimes we are lulled into a sense of complacency with mature payment channels and focus all our efforts on the emerging channels or payment products. How long has it been since you have done a risk evaluation on your ATM delivery channel?

David LottBy David Lott, a retail payments risk expert in the Retail Payments Risk Forum at the Atlanta Fed