Adversaries may add junk data to protocols used for command and control to make detection more difficult.(Citation: FireEye SUNBURST Backdoor December 2020) By adding random or meaningless data to the protocols used for command and control, adversaries can prevent trivial methods for decoding, deciphering, or otherwise analyzing the traffic. Examples may include appending/prepending data with junk characters or writing junk characters between significant characters.
Previously unseen applications generating outbound connections with atypical data flow characteristics, such as excessive data with no return response.
Processes generating large outbound connections with disproportionate send/receive ratios, often to uncommon ports or hosts, potentially inserting meaningless data into protocol payloads.
Outbound traffic with anomalous payload sizes and patterns from non-networking processes, often observed via packet inspection or connection logs.