ATT&CK MATRIX
Reference · MITREThe full MITRE ATT&CK Enterprise kill chain — every tactic column and technique cell, collected fresh from MITRE's public STIX. Cell intensity = how many tracked threat groups use the technique; ◆ = cited in advisories we collect. Click a technique for detail; filter by group to see one actor's playbook.
Adversaries may use port knocking to hide open ports used for persistence or command and control. To enable a port, an adversary sends a series of attempted connections to a predefined sequence of closed ports. After the sequence is completed, opening a port is often accomplished by the host based firewall, but could also be implemented by custom software. This technique has been observed both for the dynamic opening of a listening port as well as the initiating of a connection to a listening server on a different system. The observation of the signal packets to trigger the communication can be conducted through different methods. One means, originally implemented by Cd00r (Citation: Hartr…