Grub Bootprompt: init=/bin/sh severity?

Headhunter123 · Guru Joined: 19 Oct 2002 Posts: 509

Hello folks,

as you might know, you can edit the Grub Bootprompt by pressing 'e'.
Replacing or adding a line like "init="/bin/sh" will start a nice little rootshell for you, once the server is started.
You can change the passwords and do everything you want. Hey, you're root!

How severe do you think this problem is? Is it a problem at all? What can you do to prevent these kind of hacks?

Thanks for answers,
Bye

Chris W · Posted: Tue Mar 21, 2006 8:44 am Post subject:

This particular exploit needs access to the machine or to the machine's console if that is a separate device. Deny that access and this is not an exploit. You cannot secure a machine that is physically insecure.
_________________
Cheers,
Chris W
"Common sense: The collection of prejudices acquired by age 18." -- Einstein

Headhunter123 · Guru Joined: 19 Oct 2002 Posts: 509

Yeah, I know. But I bet 99% of all Linux desktop installations are unguared, and I bet another time that 99% of all Linux Users think their installation is more secure than the nextbest WindowsXp.
I tell you: With init=/bin/sh it ain't!

Is there any change to disable this security hole by design?

Chris W · Posted: Tue Mar 21, 2006 10:03 am Post subject:

GRUB includes an ability to set a password on the interactive features of the boot manager.

http://www.gnu.org/software/grub/manual/html_node/Security.html#Security
_________________
Cheers,
Chris W
"Common sense: The collection of prejudices acquired by age 18." -- Einstein