Turn off your network interfaces
Seriously though, just don't take anything for granted - Do not assume you are secure just because you are using something like SSH, VPN, telnet, etc...
Getting back to getting an xterm on your machine - have you had any luck?
If you're on a Windows PC, you might try PuTTY - it masqurades as an xterm via telnet or ssh, so you can cut and paste via the mouse, view color text, and it's highly configurable...