Willie Sutton is often quoted as saying he robbed banks because that’s where the money is. Though the quote is apocryphal, it could very easily be used to summarize the attitude of attackers targeting automatic teller machines (ATMs).
Using malware to target ATMs is not new. However, researchers at multiple security firms recently turned a spotlight on an attack affecting ATM machines in Mexico. It begins with a picked lock and ends with a machine spitting out money in unauthorized transactions.
According to researchers at Symantec, after picking the lock and gaining physical access to the machines, the attacker inserts a new boot disk into the CD-ROM drive that installs the Ploutus malware.
“The criminals created an interface to interact with the ATM software on a compromised ATM, and are therefore able to withdraw all the available money from the containers holding the cash, also known as cassettes,” Symantec’s Security Response team. “One interesting part to note is that the criminals are also able to read all the information typed by cardholders through the ATM keypad, enabling them to steal the sensitive information without using any external device.”
Ploutus runs as a Windows service named NCRDRVPS. The attackers created an interface to interact with ATM software on a compromised ATM through the NCR.APTRA.AXFS class. The malware was developed with .NET technology and obfuscated with the Confuser 1.9 software, and its binary is PloutusService.exe.
According to Symantec, the malware generates a randomly assigned number for the compromised ATM machine. It then sets a timer to dispense money. This only happens within the first 24 hours after it was activated.
The malware was spotted last month on ATM machines in Mexico.
“The emergence of new malware with ability to directly extract cash from ATMs is a very alarming sign for self-service device security,” Stanislav Shevchenko, chief technology officer at Russian security firm SafenSoft, blogged Sept. 27. “Malware like this allows the cybercriminals to skip the whole process of cash withdrawal they have to take part in after using traditional ATM trojans and skimmer-like devices to steal the plastic card information.”