Windows 10 comes with the finger command, an ancient computer network tool.
You can still use it to lookup weather information, for example 🙂
It establishes a TCP connection to the hostname/IP address after the @ character, using destination port 79. And then it sends the text before the @ characters in ASCII, terminated with carriage return & line feed.
After that, it reads the reply, displays it, and closes the TCP connection.
finger.exe is not proxy-aware.
Port 79 is not hardcoded as an integer in finger.exe: the port is identified by service name “finger” (UNICODE), which is defined in the services list (%SystemRoot%\system32\drivers\etc\services). GetAddrInfo uses this list.
If you replace “finger” with “http\x00\x00” (UNICODE) in finger.exe (via binary patching, a shim, …), the finger command will connect to port 80:
As noted by many, finger.exe can be (ab)used to exchange information and files. Here I had my own go at it with finger.exe & Excel:
Didier Stevens 