Containment, eradication, and recovery
Once you have a good understanding of the attack you are dealing with, it's time to apply some containment measures.
The most common thing you can do is to block connections to the command and control servers. Without this, the threat actors can hardly do any harm to the network – of course, if they didn't deploy some scheduled tasks, for example, which'll run another backdoor with another command and control server.
So, it may be a good idea to isolate the whole network from the internet. But, of course, it depends on the stage of the attack life cycle. If you managed to detect it at an early stage, isolating the whole network may not really be a good idea, but if the threat actors spent a month inside, well, why not!
Another thing many ransomware affiliates commonly use is legitimate remote access applications. Here are some examples commonly seen during ransomware incident response engagements:
- TeamViewer...