Security Of Linux's Singal User Mode?

[jedipi 0]

i currently tried linux's singal user mode.After login as a super user, I can change the password for root.How can this happen??After I did some research, I found that password can be assigned to grub in order to prevent this problem.Does anybody know how to do that??

[qwijibow 0]

In single user mode, securety is non existant.
However, to boot into single user mode, someone would need physical access to your computer, to enter the single user command before linux boots (in the grub screen)

If your computer is left un-supervised around people you do not trust, you can add a password to grub like you said. but someone could circumvent grub with a bootable rescue CD / rescue floppy.

so a password on grub is not enough, you also need a password your BIOS, to stop people from booting CD's or floppy's

But the bios password can be circumented by taking the case off, and re-setting your bios.

In Other words, Unless you weld your case shut, anyone who has hands on access to your computer can circument securety.

For more info, read.
http://forums.xisto.com/no_longer_exists/

to answer your equstion....
as root run the command

marla root # /sbin/grub-md5-cryptPassword: helloworldRetype password: helloworld$1$zShlv0$twgu4mY7e72psiK1PEbxe1

the output string at the bottom is your encrypted password.

open up /boot/grub/menu.lst with a text editor, and add the line

password --md5 $1$zShlv0$twgu4mY7e72psiK1PEbxe1

to the TOP of the file, must be the first line.

ofcourse replace the encrpyred password i gave with one of your own.