Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts. By impersonating legitimate protocols or web services, adversaries can make their command and control traffic blend in with legitimate network traffic.  

Adversaries may impersonate a fake SSL/TLS handshake to make it look like subsequent traffic is SSL/TLS encrypted, potentially interfering with some security tooling, or to make the traffic look like it is related with a trusted entity. 
Protocol Impersonation
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1001/003  external_id: T1001.003     source_name: University of Birmingham C2  description: Gardiner, J.,  Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.  url: https://arxiv.org/ftp/arxiv/papers/1408/1408.1136.pdf     