Find sigma rule 
Attack: Exfiltration Over C2 Channel
Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.
MITRE
Tactic
- exfiltration
technique
- T1041
Test : Text Based Data Exfiltration using DNS subdomains
OS
- windows
Description:
Simulates an adversary using DNS tunneling to exfiltrate data over a Command and Control (C2) channel.
Executor
powershell