Level 18: No Shell For You

This level is a bit of a prank. You log in via SSH, and the very second you arrive, the server runs a startup script that boots you. Connection closed. No interactive shell, no ls, nothing.

It feels like you're locked out, but there's a loophole. SSH doesn't actually require an interactive shell to work. You can tell SSH to execute a specific command on the remote server and then exit immediately.

Since the server kicks you out after the initial command is processed, you can just bypass the shell entirely and tell the server to cat the flag for you.

ssh ghost17@204.168.229.209 -p 2222 'cat flag'

The server executes the command, spits out the password, and then kicks you out. Mission accomplished.

Result: REDACTED

TL;DR: If a server kicks you on login, use SSH to execute a single command (ssh user@host 'command') to bypass the interactive shell requirement.