Malware that steals from point-of-sale systems detected

A data stealer designed to collect users' personally identifiable information from point-of-sale (POS) systems has been detected.

Originally detected in early December by researchers at Seculert, an Israel-based advanced threat detection company, follow-up research by Trend Micro said that the malware was found in POS systems at hotels and other businesses. “Currently, the arrival infector remains undetermined,” said Jason Pantig, senior threat response engineer at the Tokyo-based security software company. However, it is unlikely that the malware is downloaded from malicious sites, as the POS systems are typically not used for web browsing.

Point-of-sale terminals are typically where payment for goods and services occur, Pantig said. "Given the wealth of data found on these payment hubs, it's expected that these are the next targets of cyber criminal activities.”

The company's analysis determined that BKDR_DEXTR.A, also known as Dexter, downloads files, sends information and checks memory for information, among other tasks.

“The center piece of the malware is its ability to collect and send certain information to a remote server,” said Pantig. Some of the data that can be stolen from POS systems includes username, hostnames, a key to decrypt the sent information, OS information and a list of running processes, he said.

This data is then presumably duplicated by remote malicious users. "The malware executable is found to be packed or encrypted and when loaded, it loads long garbage code to decrypt the actual code," he said. However, this decryption routine involves only a combination of XOR and ADD instructions, with the use of a hardcoded key. The perpetrators behind Dexter malware probably did this to make analysis difficult, he added.

Trend Micro further said that unlike other spyware, like Zeus and SpyEye, this malware does not directly infect users' systems to gather data, such as payment card details. “Instead, the crooks behind BKDR_DEXTR figured that they can generate the same result by infecting certain POS systems,” Pantig said.

Updated: Jan. 2, 2013. A version of this piece originally appeared on our sister site SC Magazine UK.

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