Security vendor Trustwave Dec. 18 publicly detailed a previously undisclosed point-of-sale (POS) malware variant known as Spark.
Various forms of POS malware have been taking aim at retailers throughout 2014, with one of the most pervasive being the Backoff malware. The U.S. Secret Service has warned that at least 1,000 retailers have been impacted by Backoff. The new Spark POS malware is unrelated to Backoff in terms of malware families; the only relation is that they are both malware variants that target POS systems.
A number of POS malware families have impacted retailers in 2014, including FrameworkPOS, BlackPoS and JackPOS. Spark is in fact a variant of the Alina POS malware family.
"We have investigated many retailers to date where Alina was discovered on the point-of-sale system; however, I am not aware of any that have been 'publicly outed' to my knowledge," Ryan Merritt, malware research lead at Trustwave, told eWEEK. "Also, to clarify further, Spark is a unique variant of Alina that hasn't been publicly discussed in detail until now."
Trustwave discovered Spark while performing investigations on multiple breaches of automotive repair and maintenance businesses, according to Merritt.
There is a suspected relationship between the JackPOS and Alina malware variants, Merritt said, as there are some similar technical behavioral components across the two malware families, including the use of custom credit card searching methods. Additionally, JackPOS emerged near the time when Alina use started to wane, he said, and there have been unconfirmed rumors that JackPOS is the successor to Alina as well as other industry reports of the Alina source code being sold on underground forums.
Both Alina and Spark go after Microsoft Windows machines.
"This [Spark] and all other discovered variants of Alina are compiled to execute on a Windows OS exclusively," Merritt said. "No observed variants have targeted Linux/Unix/Mac to date."
From an infection standpoint, Spark does not spread on its own, according to Merritt. Rather, it is a hacking tool criminals designed specifically to harvest credit card data and send that data back to a system the attackers control.
"Attackers deploy this tool once they have compromised a victim system, most commonly by guessing a weak password to a remote access service installed on the point-of-sale system," Merritt said.
Detecting Spark is not particularly easy as the malware's authors have taken measures to avoid detection and to keep the code stealthy. Merritt said Spark uses a technology known as AutoIT, which makes it easy for attackers to alter the malware's file signature to avoid antivirus (AV) detection. That said, Merritt noted that as in any cat-and-mouse game, AV quickly catches on to new variants and will eventually detect the new signature or common malicious behavior.
"To further protect themselves, retailers should isolate their payment networks and keep their systems responsible for accessing credit card data hardened by applying strict security policies such as strong passwords and disabling any unused services," Merritt said. "Network protections such as IDS/IPS [intrusion prevention/detection systems] and egress filtering can also detect infection and potentially limit automated exfiltration of the stolen credit cards."
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.