[225] in linux-security and linux-alert archive
Re: LILO hole
daemon@ATHENA.MIT.EDU (Jon Green)
Wed May 3 05:12:56 1995
To: "David A. Blankenship" <dblanken@Paranor.pc.cc.cmu.edu>
Cc: linux-security@tarsier.cv.nrao.edu
In-reply-to: Your message of "Tue, 25 Apr 1995 08:49:18 EDT."
<Pine.3.89.9504250810.A85-0100000@Paranor.pc.cc.cmu.edu>
Date: Thu, 27 Apr 1995 22:20:26 -0500
From: Jon Green <jcgreen@fire.com>
[mod: Questions on where to get sulogin to the author, please. Quoting
trimmed. --okir]
> It seems that there is a rather amusing security hole in lilo. If you
>enter 'linux single' at the boot prompt it boots linux single user. Doesn't
>ask for a password or anything. Of course it also mounts the hard drive
>read-only, but its very easy to remount it read/write.
Actually, this is pretty simple to fix. I have this in /etc/inittab:
# Shell to run in single user mode.
su:S:wait:/sbin/sulogin
And from the handy man pages:
SULOGIN(8) SULOGIN(8)
NAME
sulogin - Single-user login
SYNTAX
sulogin [ tty-device ]
DESCRIPTION
sulogin is invoked by /etc/init prior to allowing the user
access to the system when in single user mode. This fea-
ture may only be available on certain systems where init
has been modified accordingly, or where the /etc/inittab
has an entry for a single user login.
The user is prompted
Type control-d for normal startup,
(or give root password for system maintenance):
-Jon
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