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Home Depot Breach May Not Be Related To BlackPOS, Target

New analysis of the malware earlier identified as a BlackPOS variant leads some researchers to believe that they are two different malware families entirely.

Reports emerged earlier this week that a BlackPOS variant discovered last month by Trend Micro was to blame for the data breach at Home Depot, raising speculation that the breach was carried out by the same group that breached Target and with the same malware. But new analysis has led some researchers to believe that it isn't related to BlackPOS at all.

As Josh Grunzweig wrote on the nuix "Unstructured" blog: "After careful review of both [malware] samples, I don’t believe the sample in question is actually part of the BlackPOS malware family. While I thought Trend Micro’s technical analysis was fantastic and overall a good read, it does not clearly identify a connection between the two samples."

Grunzweig points to a number of ways in which the malware variants differ:

  • Subsystems were configured differently. BlackPOS was written with a Windows subsystem, while the new malware was written with a console option.

  • Installation differs. BlackPOS was configured to be run without any command-line arguments, while the new malware uses several command-line arguments. Also, the new malware uses a service dependency technique that BlackPOS does not. The new malware adds itself as a dependency to another service, to prevent itself from being easily removed.

  • String obfuscation techniques differ. BlackPOS uses character shifts, while the new malware uses an XOR encryption routine.

  • Although both malware variants dump harvested card data to a fake DLL file, they format and obfuscate that data differently. BlackPOS includes a command in the data format and obfuscates it with a customized version of Base64. The new malware includes the victim's IP address in the format and obfuscates it with a substitution cipher.

  • Both malware move the harvested data through network shares, but their techniques differ. BlackPOS uses direct system calls, while the new malware writes out to a batch script and executes with a call to a CreateProcessA() Windows API.

  • The malware calls to different APIs for process enumeration vary. BlackPOS uses EnumProcess(), and the new malware uses CreateToolhelp32Snapshot.

  • Lastly, BlackPOS uses a more focused whitelist approach to finding processes to target, while the new malware uses a blacklist. 

Jeremy Humble and Nick Hoffman from CBTS Advanced Cyber Security point out that the two pieces of malware also use different algorithms to process credit card data.

Said Grunzweig, "A single difference, or perhaps a couple of differences, might be the result of minor changes in a code base. However, the number and degree of variances between these two samples are a clear indication that they were more than likely coded by different people."

The bottom line is even if the malware isn't a BlackPOS variant, it's still powerful. "While this particular sample may not be the newest variant of BlackPOS, it is still very much a serious threat. It employs a number of simple tactics that make it difficult to detect without specific knowledge of the malware family itself," he said. "Overall, I think we can all agree that no matter what this family of malware is called, it still certainly has the capability to steal a wealth of information."

Sara Peters is Senior Editor at Dark Reading and formerly the editor-in-chief of Enterprise Efficiency. Prior that she was senior editor for the Computer Security Institute, writing and speaking about virtualization, identity management, cybersecurity law, and a myriad ... View Full Bio

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Sara Peters
Sara Peters,
User Rank: Author
9/15/2014 | 2:33:42 PM
Re: PoS malware a growing threat
@GonzSTL   All great points. The most professional malware authors are going to build on success (whether it's theirs or someone else's) not reinvent the wheel. But this is, I think, the most important thing you said:  "More importantly, why didn't these breached companies have some mechanism in place that examines data leaving their organizations and prevents data from inappropriately going out?"   I think we're seeing again and again and again that organizations aren't watching what's leaving, which is making it possible for these breaches take place over the span of months. 
User Rank: Ninja
9/12/2014 | 10:26:57 AM
Great write up!
Thanks for providing the technical details on the code.

Always nice to have some in depth reporting, and it is interesting to see the differences so cleanly laid out by someone who has access to the details.

Very much appreciated, great article!
User Rank: Ninja
9/12/2014 | 9:43:45 AM
Re: PoS malware a growing threat
Agreed, but is it really surprising that there is a potentially new malware strain that is equally nasty? I used to write software and one of my main strategies was to never reinvent the wheel, but instead, improve and optimize it. If I were to create new malware, I would look at the existing ones that have had great success, pick out the particularly good and clever aspects of each one, and combine them all into a new product, optimized and sophisticated enough to hide itself using proven methods. I view this as a natural evolution of malware; the bad guys are quite clever, and surely that is exactly what they are doing. Why is this shocking? In fact, why isn't this anticipated? Why aren't the anti-malware products equipped with this anticipated behavior detecting techniques in their heuristic algorithms? Maybe they are, but apparently not quite up to the challenge, supporting the stigma that the good guys are always playing catch up to the bad guys.

More importantly, why didn't these breached companies have some mechanism in place that examines data leaving their organizations and prevents data from inappropriately going out? Plain text data traversing the network can be easily examined and regulated for controlled content, to prevent sensitive data leakage. Encrypted data with external destinations should be suspicious and therefore carefully monitored and controlled. I am curious - did any of these breached companies even fully implement the SANS 20 Critical Security Controls at the very least, or did they simply put cursory systems in place that allowed them to mark a check in the appropriate compliance checkboxes? One of the biggest pitfalls in security is assuming that compliance means security, and I wonder if any of these companies were guilty of that.
Marilyn Cohodas
Marilyn Cohodas,
User Rank: Strategist
9/12/2014 | 8:18:15 AM
Getting the facts straight
With the almost daily reporting of retail breaches these days, it's tempting for the news media to jump to quick  conclusion that further analysis doesn't bear out. Thanks for the thoughtful reporting on this story, Sara, and for keeping the record straight at Dark Reading, Sara. 
User Rank: Ninja
9/11/2014 | 4:57:26 PM
PoS malware a growing threat
PoS malware has characterized the 2013, their evolution is the results of continuous developments offered in the underground market. Exfiltration techniques and evasion methods are making these threats even more complex and hard to analyze.

If the news in the title is confirmed security community will face with a new strain of malware with features similar to BlackPos malware that is equally dangerous.
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