Lost root password lilo

From LinuxNewbie

Forgotten Root Password
by Jeffrey Howard
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You've forgotten the root password to your machine.
Platform
Linux with the lilo boot loader.
Solution
Reboot your linux machine. At the lilo prompt, type:
linux 1

assuming linux is the tag you have in lilo for your linux kernel.
Typically, this boots linux with all the priveleges of root. Just use passwd to change root's password to whatever you want. I'm sure there are also slighly more convoluted ways of accomplishing the same thing by making a bootable linux floppy from which you can mount hard drive partitions.

Yes, this does mean that it's fairly simple to get into a linux box if you're sitting in front of it. Some people try to fix this problem with a BIOS password, so the machine won't boot without a password. Of course, with enough time to unscrew the case and tamper with the motherboard, this too can be circumvented. Alternatively, someone can just take the hard drive out of your machine altogether. The point is that if someone is sitting at your machine, they can do just about anything anyway. What physical security measures you adopt depends on how likely you think it is for people to want to gain physical access to your machines to compromise them.