If none of the C2 servers respond and the end of the configured hosts list is reached, the modulo operation returns zero, thus host_index is equal to zero and the backdoor waits for the number of milliseconds stored in the &lt;TimeLong&gt; registry key. In our case, this was set to one minute. Then, it starts again and tries to reach the configured C2 servers, again host-by-host, until one response. If a connection to one of the configured C2 servers was set up successfully, the backdoor stays in the inner while loop (C2 control loop) and checks for commands every &lt;TimeShort&gt; number of milliseconds. C2_GetCommand_ComHandler handles the communication with the C2 server. It leverages the Windows WinHttp API similar to this Microsoft example and receives the C2 command along with its parameters. The adversaries use SSL/TLS to encrypt the C2 traffic