Network Security

The Importance of Retrospective Network Security

Network Security

We are experiencing a new phase in our vision of network security. There is currently no quick fix solution, no 100% proof network security protection/prevention tool or product. There is always zero-day or purposely built (very focused, low spread) APT malware that current vendors are unable to detect at the time of the breach.

Hence total prevention is a myth.

Most of the current network security solutions offer only Point-In-Time detection/prevention. Namely they inspect the traffic when the traffic goes via the firewall and if they deem the traffic is clean  or unknown, at that exact time, they will allow it and forget about it. That could lead to malware passing through and being undetected for long periods of time. All vendors rely on intercepting the C&C communication to the botnet servers but not all malware uses such a centralized operation method so that cannot be considered a proven method of detection. That is why most of the vendors will apply their own sandboxing solution, namely send all files of unknown malware type to the cloud where they will be detonated in a controlled environment and the result of their execution will be deemed malicious or not by machines or sometimes humans. Upon discovery of malicious actions, the file is marked as malware and an update is shot out to all vendor appliances out there so they can intercept and drop such files. That process however takes time (typically more than 8 hours) and usually stops more than 96% of the malware spread (it depends on how quickly the different vendors discover that the file is malicious and how quickly the update is sent out) and that percentage was deemed high-enough for most companies.

What about that 4% though? I am sure any business owner would not like to be in this position and would like greater protection and value for their money. When a mere 4% can cause 100% of your security problems, you’re not protected.

Cisco is the only vendor in the NGFW market that currently has its vision also set on the retrospective side of the network security, the so-called After-The-Attack phase. Cisco uses the combination between Firepower and AMP for both network and endpoint to be able to provide threat context and to pinpoint the progress and spread of the malware in historical time so you will know exactly when and how the malware moved in your network, which hosts were infected so that you can immediately deploy mitigation techniques. First restrict the malware, block the effect of the malware and finally remove the malware that has already breached your network. Without this continuous analysis, the attack can run rampant on the network and it will be extremely difficult to determine the scope of the outbreak and the root cause or provide on-time/adequate response. Here is an example of such an event and how Firepower and AMP deal with it.

The following 4 simple steps represent how Firepower and Amp works with zero-day malware files:

  1. Unknown file gets downloaded to a client ip (1.2.3.4 for example) via http application with Firefox, the file is then allowed to reach the endpoint. The unknown file is sent to the cloud to be detonated and given a verdict.
  2. The Firepower tracks the movement/copying of the file within the network so it sees the file being propagated via any protocol at any time. For example, the file gets copied to another host 1.2.3.5 via SMB at 12:41 AM on the 1st of Dec 2016.
  3. Within 30min the same file gets replicated to 5 more devices within the internal range, all via SMB. The Firepower has a map of the file trajectory with hosts and timing of the movements.
  4. Two hours since the file was first seen, Cisco Security Intelligence Cloud had reached a verdict that the file in question is in fact malicious. From now on all Cisco AMP and Firepower enabled devices will drop that file upon encounter and alarm/log, but here comes the difference between Cisco and other vendors, namely the retrospective part. In our example, all future transfer of the files will be blocked and the file itself will be quarantined on all endpoints that have this file (requires AMP for endpoint), even more the administrators can leverage the trajectory map and verify the malicious file has been quarantined/removed and hosts have been remediated.

Abbreviations:

APT – Advanced Persistent Threats

C&C – Command and Control

NGFW – Next-Generation Firewall

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