A newly discovered Point of Sale (PoS) malware is being delivered via a dropper that is manually loaded and executed on the targeted systems, Arbor Networks Security researchers warn.
The new threat was associated with command and control (C&C) servers used by Flokibot in a campaign targeting Brazil. Dubbed LockPoS, the malware appears to have been compiled in late June and to use a dropper that injects it directly into the explorer.exe process.
After being manually loaded and executed, the dropper continues by extracting a resource file from itself. The resource contains multiple components that are injected into explorer.exe and which act as a second-stage loader. Next, it starts decrypting, decompressing, and loading the final LockPoS payload.
While analyzing the malware, Arbor Networks researchers discovered it uses a regular “registry run” method for persistence. The malware obfuscates important strings using XOR and a key of “A”. It also stores an initial configuration unencrypted as a binary structure.
The malware’s communication with the C&C server is performed via HTTP, using a very telling User-Agent. Information sent to the server includes username, computer name, and bot ID, Bot version (1.0.0.6), CPU, Physical memory, Display devices, Windows version and architecture, and MD5 hash of currently running sample.
“The malware’s PoS credit card stealing functionality works similarly to other PoS malware: it scans the memory of other running programs looking for data that matches what credit card track data looks like. Here’s a snippet of the matching function,” the security researchers explain.
Until now, the new malware has been distributed via a Flokibot botnet, and, with both threats sharing a common C&C server, the researchers believe that same threat actor controls both of them. Because the Flokibot campaign associated with the server was targeting Brazil, the researchers believe LockPoS will target the same country as well.
Although the same C&C at treasurehunter[.]at was used in another PoS malware campaign in what FireEye referred to last year as TREASUREHUNT, Arbor Networks says that LockPoS is a different malware family from TREASUREHUNT.
“It is currently unclear whether LockPoS is an exclusive malware associated with one threat actor or whether it will be sold on underground forums like Flokibot was. Based on the internals of the malware described in this post, LockPoS seems to be coded well and stable, but doesn’t particularly raise the bar when it comes to ‘highly advanced malware’, the researchers note.
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