Friday, January 24, 2014

How can companies prevent cyber attacks like that of Dec 2013 Target credit card data theft ?

1//24/2014 By: Arvind Jain

By now we all know that passionate hackers are very smart and they will always have a edge over whatever known systems we can create (Firewall, IPS etc). Even the best SIO (Security Intelligence Operations) team cannot possibly know of each and every malware in advance so a traditional approach of IPS or Malware detection based on signature is so stone age thing now.

So what could have been done at Target? I am sure many experts are pondering over it but here is my simple thinking. A combination of proactive people, process and tools would have prevented it.

We need people for behavior analysis or analytics.  BlackPOS creators and Hackers in general know what a Firewall can do. So they timed data transfer to normal business hours, merged it with FTP traffic and used internal dump servers in Targets own network. This is what I gathered from iSight comment in the WSJ article today.

"ISight, hired by the Secret Service and Department of Homeland Security to help with the investigation, said the bug had a "zero percent antivirus detection rate," meaning even updated security software couldn't tell it was harmful.  So a endpoint security system or antivirus software would also have been ineffective to detect the malware.

This is where you need a joint effort on part of system, people, and process to detect anomalies.  Something like a Cyber Threat Defense solution (like the one offered by Cisco) is a good way to detect patterns and flag them.

The hack involved several tools, a Trojan horse scanned the point-of-sale system's memory for card data which was stored unencrypted in memmory. Another logged when the stolen data was stashed inside Target's network. Yet another sent the stolen data to a computer outside the company. The coordination of those functions was complex and sophisticated, but could have been easily seen as an anomalous pattern.

Like if there is traffic jammed up in freeway you know something is wrong ahead. For that matter if all traffic goes to a different side than normal for that route then also you know something is not right. To detect anomalous activity, you have to look at traffic timing, volume, direction etc. to detect activity.

These are good indicator that something has happened and potentially it requires immediate attention from people and processes. You could then take the traffic flow (using a tool like NetFlow) and look for anomalous traffic patterns.  You would have encountered something that is never before seen and that would have triggered deep packet inspection of dump files.

Typically Malwares siphoned data and stored it in local Intranet (to disguise it as internal traffic over a temporary NetBIOS share to an internal host inside the compromised network) and then attempt to send the data to the attacker over a legitimate call like via FTP or HTTP.  Compromised data was collected in .DLL files (in this case, track data, which includes all of the information within the magnetic strip) and is periodically relayed to an affected “dump” server over a temporary NetBIOS share drive.  In this particular case the DLLs weren't malicious (they just contained normal data so no system could have tracked it without insight from people or Target IT staff).

Tools like Lancope StealthWatch help you detect such anomaly. The dump server was not a host that the POS systems were required to communicate with. So when POS systems attempt to communicate to one another or to a unidentified server a Host Lock Violation alarm is generated. Similarly once the data started to be sent to the dump server, it could have triggered a Relationship High Traffic or potentially a Relationship New Flows alarm.

Internet Control Message Protocol (ICMP) is one of the main protocols of the Internet Protocol Suite used by network devices, like routers, to send error messages indicating, for example, that a requested service is not available or that a host or router could not be reached. ICMP anomalies can be detected using network-monitoring tools provided by companies like Cisco or its recent acquisition

So you do have all the tools at your disposal, all that was needed was a good brain with commonsense to do correlation between the series of activities that were happening anomalously and could have been detected by monitoring tools.


Of course if you do not have time for all these or the tools or the in-house security expertise, Cisco Advanced Services for Managed Cyber Security is at your service. Feel free to reach out to me for recommendations.


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