Test callback functionality
Callbacks are malware communications seeking instructions. An adversary will test their malware to ensure the appropriate instructions are conveyed and the callback software can be reached. 
Detectable by Common Defenses (Yes/No/Partial): No
Explanation: Adversary controls the test and defender likely has no visibility.
Difficulty for the Adversary
Easy for the Adversary (Yes/No): Yes
Explanation: Adversary controls or acquires all pieces of infrastructure and can test outside of defender's visibility.
- Tony Lee. (2012, December 11). Testing Your Defenses - Beaconing. Retrieved March 9, 2017.