We frequently encounter password stealers and backdoors in computers after their owners have browsed unsafe websites or opened unknown email attachments. It is more unusual, however, to see these malware directly implemented in banks’ automated teller machines. In these cases, Trojans have to be installed by people who have physical access to the machines. Data collecting and malware removal would need yet another visit or visits. It should seem obvious that such malware installation requires a high level of “cooperation” from the bank staff.
One of the first attacks occurred in Russia more than one year ago. It was announced in January 2009 when Diebold Inc. released a security fix for its Opteva Windows-based ATMs. At that time, the company said some suspects were apprehended. But it seems the gangÂ was not fully dismantled. In May, we heard of new suspicious files discovered in Eastern European ATM machines. The security firm Trustwave published a study concerning this matter. The software had been updated and new virtual robberies had been launched. On June 3, Â The Register also raised public awareness by covering the story.Â
When active, the Trojan intercepts transactions and records them on log files. To control an infected ATM, the attacker uses dedicated credit cards that allow him to activate some administrative rules. Via the ATM’s display, he can select various options from the keypad to display statistics (numbers of transactions, cards, keys), print collected data, force the machine to dispense all its cash, uninstall the malware set, and reboot the ATM. Unfortunately, I was unable to test such malware in a real environment (I do not have a spare ATM lying around), but looking at the samples is very instructive. As in the previous attacks, the vulnerable ATMs are equipped with the Diebold Agilis 91x software, and the attacker can examine the registry to display version and statistics:
Targeted currencies are the U.S. dollar, Russian ruble (RUR), and the Ukrainian Hryvnia (UAH):
The attacker can also-–through a password-protected routine–control the currency-dispensing ATM cassette:
We are not aware of any such attacks outside Eastern Europe, but we encourage financial institutions to verify the integrity of their ATM systems. Be proactive!
The known versions of this malware are detected by McAfee VirusScan as PWS-BoldDie. Many generic and unclassified versions can be detected under the name Generic Backdoor!bw.