Password protection for the BIOS (or BIOS equivalent) and the boot loader can prevent unauthorized users who have physical access to systems from booting using removable media or attaining root privileges through single user mode. But the security measures one should take to protect against such attacks depends both on the sensitivity of the information the workstation holds and the location of the machine.

For instance, if a machine is used in a trade show and contains no sensitive information, than it may not be critical to prevent such attacks. However, if an employee's laptop with private, unencrypted SSH keys for the corporate network is left unattended at that same trade show, it could lead to a major security breach with ramifications for the entire company.

On the other hand, if the workstation is located in a place where only authorized or trusted people have access, then securing the BIOS or the boot loader may not be necessary at all.