Use Any.Run or a local VM with Wireshark to monitor network callbacks.
For .NET files, use dnSpy ; for compiled C/C++, use Ghidra . Common Challenge Objectives 21018.rar
If the RAR contains .exe , .scr , or .bat files, they should only be handled in a . Use Any
Use the file command to confirm the magic bytes (Rar! ....). for compiled C/C++
Use unrar l 21018.rar to view file names without extracting.