What is the purpose of locking the BIOS with a password?

[Executioner]

I bought some used laptops that had a locked BIOS. These laptops were from Dell. The one that I unlocked last month I used this site: https://bios-pw.org/ by entering in the code in the BIOS; however, today I got another Dell Latitude 5580 with a locked BIOS. Got this one unlocked also, but my question is: what is the security purpose of locking the BIOS?

 

[cjcox]

Keeps the less hard working folks out of making changes to your bios.

Remember, all security is just obscuring. Some things being "tougher" than others.

I mean, you might still use passwords somewhere (or a password manager)....

 

[toast0]

A BIOS password is one component of tight security. If your OS is secure and has a secure password, but no encrypted disk; someone could boot from a usb/floppy/PXE and read the disk and save it somewhere. If you have an encrypted disk, someone could still copy the disk, and maybe plant a pre-boot keylogger (secure boot is supposed to help with that). But if your bios is password protected, they can't change the boot config. Of course, the history of BIOS password security isn't very good; my college in the 90s had locked down systems, but the BIOSes accepted several of the well know award backdoor passwords.

On most machines, you can easily clear the password if you open the machine; laptops are sometimes a bit trickier though. If it has removable storage, you can still mess with the storage if you can open it up, and few people hermetically seal their computers... Ultra paranoid will use full disk encryption with keys in the tpm and the tpm set to erase keys if the case is opened. Kind of a big pain though.

 

[Stugots]

...boot from a usb/floppy/PXE and read the disk and save it somewhere...

This.

Also to prevent people that don't know what their doing from tinkering around in the firmware and change some setting that would prevent the system from booting or impact performance.

 

[Westwood]

This.

Also to prevent people that don't know what their doing from tinkering around in the firmware and change some setting that would prevent the system from booting or impact performance.

Hey! That's me!

I put game mode or something on and it wouldn't boot. switched it off and it was fine. no idea.

I get all nervous in BIOS.