How does the article's Downloader (C2) communicate between the server and client, and what information does the client send?

The server listens on a specified port and parses POST data, while the client connects periodically, sending system information such as the hostname and operating system version. The server can then respond with control commands, which the client executes using `child_process.exec`. If no command is received, the client sleeps for a set interval before retrying. This mirrors command-and-control patterns discussed in Penetration Techniques - Deletion and Bypass of Windows Logs.