Security researchers have found a sophisticated malware program that may have been used recently by a gang of hackers to steal more than US$350,000 from ATMs in Thailand.
A sample of the new malware, dubbed Ripper, was uploaded to the VirusTotal database from an Internet Protocol address in Thailand last week, shortly before local media reported that hackers used malware to steal 12.29 million Baht from 21 ATMs in the country.
The incident forced the state-owned Government Savings Bank to temporarily shut down all of its ATMs made by one vendor so they could be checked for malware, the Bangkok Post reported last week.
Aside from the Ripper sample coming from Thailand, other indicators suggest this program was the one used to pull off the recent ATM heist in the country, security researchers from FireEye said in a blog post Friday.
Based on their analysis, Ripper targets the same ATM brand as the one affected in Thailand, as well as two others. It can disable the ATM's local network interface, which according to some public sources, happened during the recent incident. The sample was also compiled on July 10, around a month before the attack was disclosed publicly.
Once installed on an ATM, Ripper waits for attackers to insert a card with a specially programmed chip. This mechanism, used for authentication, has been used by other ATM malware in the past. Once authenticated, the attacker can issue commands to dispense up to 40 banknotes from the ATM's cash cassettes.
Ripper also has other features seen in past ATM malware programs, including Padpin (Tyupkin), SUCEFUL and GreenDispenser. For example, it features a secure delete option that can be used to destroy forensic evidence, the FireEye researchers said.
ATM malware can be deployed in several ways. One is by insiders who work as technicians and service ATMs. Another is through the CD-ROM or USB ports of the ATMs that are available after opening their covers with special service keys, which can be bought online. This second method can only be used to target ATMs that sit outside, in unsecured places, which seems to have been the case in Thailand.