The news that Target stores lost 110 million customers' credit card details in a hacker intrusion has illustrated just how grave a risk malicious software presents to the average person and the businesses they patronize. Brian Krebs has good, early details on the software that the hackers used on infected point-of-sale terminals at Target, and some good investigative guesses about who planted it there and how they operated it.
Krebs suggests that a Russian hacker called "Antikiller" may be implicated in the Target hack, and that Antikiller is, in any event, the author of the malware used against the point-of-sale systems.
According to a source close to the investigation, that threatexpert.com report is related to the malware analyzed at this Symantec writeup (also published Dec. 18) for a point-of-sale malware strain that Symantec calls "Reedum" (note the Windows service name of the malicious process is the same as the ThreatExpert analysis –"POSWDS"). Interestingly, a search in Virustotal.com — a Google-owned malware scanning service — for the term "reedum" suggests that this malware has been used in previous intrusions dating back to at least June 2013; in the screen shot below left, we can see a notation added to that virustotal submission, "30503 POS malware from FBI".
The source close to the Target investigation said that at the time this POS malware was installed in Target's environment (sometime prior to Nov. 27, 2013), none of the 40-plus commercial antivirus tools used to scan malware at virustotal.com flagged the POS malware (or any related hacking tools that were used in the intrusion) as malicious. "They were customized to avoid detection and for use in specific environments," the source said.
That source and one other involved in the investigation who also asked not to be named said the POS malware appears to be nearly identical to a piece of code sold on cybercrime forums called BlackPOS, a relatively crude but effective crimeware product. BlackPOS is a specialized piece of malware designed to be installed on POS devices and record all data from credit and debit cards swiped through the infected system.
A First Look at the Target Intrusion, Malware [Brian Krebs/Krebs on Security]
