TA0011 · COMMAND AND CONTROL
Non-Standard Port
Adversaries may communicate using a protocol and port pairing that are typically not associated. For example, HTTPS over port 8088 or port 587 as opposed to the traditional port 443.
Detect it with
Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used. Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server).
Why it matters on shift
Non-Standard Port is one of the concrete ways adversaries achieve command and control. 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 command and control, the next tactic is usually Exfiltration. Search your telemetry for the transition before closing the ticket.
Kill-chain context