Linux computer console is a physical device to operate a computer / server. Here are few steps which, if taken, make it more difficult for an attacker to quickly modify a system from its console.
Set BIOS Password
The BIOS is boot firmware, designed to be the first code run by a PC when powered on. It controls many important system parameters, including which devices the system will try to boot from, and in which order. Assign a password to prevent any unauthorized changes to the BIOS configuration. Reboot the server. Press special key like F2 (this key may vary from system to system). Go to BIOS configuration menu to add a password. Save and close the bios by pressing F10 (again key may vary)