The process of setting up and using dnscat2 is documented in this article. The tool consists of a Ruby server and a small C client, and can be used to quickly establish an encrypted covert channel between two computers over the Internet using DNS traffic. Once set up, the tool is evaluated by exfiltrating data out of a network that has a pfSense firewall at the perimeter blocking direct outbound DNS requests from client machines, and also running the Snort IDS. It is is seen that a reverse shell is successfully sent out of the network and no IDS alerts are generated.
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