Each script scans the pcap file looking for one of the main symptoms on the network that there is a command and control server. Therefore each script produces a log file to show the results of its analysis. Note that disrupting C2 can prevent a malware infection from turning into a more serious incident such as a data breach. In fact, many large-scale cyberattacks were initially discovered when researchers noticed C2 activity.
These scripts parse pcap files and produce log files (typical of Zeek). As objectives they have:
- looking for long connections, based on duration
- seeking persistent connections, base on times "talked" to each other
- count of equal-sized packets per connection
- geolocation of the IPs , with libmaxminddb software and GeoLite2 city database
- count how many fully qualified domain names are associated with each domain
- check if there are any problems with SSL certificates, such as expired or self-signed
- check if there are any unexpected usage or unexpected application running across a well-known ports
At the following link you can find complete documentation for Zeek installation and use of scripts.