TA0003 · PERSISTENCE
Port Knocking
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.
Detect it with
Record network packets sent to and from the system, looking for extraneous packets that do not belong to established flows.
Why it matters on shift
Port Knocking is one of the concrete ways adversaries achieve persistence. Recognising it in telemetry lets you name the technique in your ticket and pivot to what came before and after.
What to look for next
After persistence, the next tactic is usually Privilege Escalation. Search your telemetry for the transition before closing the ticket.
Kill-chain context