[35348] in bugtraq
Re: Unprivilegued settings for FreeBSD kernel variables
daemon@ATHENA.MIT.EDU (Eygene A. Ryabinkin)
Fri Jun 18 14:44:37 2004
Date: Thu, 17 Jun 2004 18:33:49 +0400
From: "Eygene A. Ryabinkin" <rea@rea.mbslab.kiae.ru>
To: bugtraq@securityfocus.com
Message-ID: <20040617143349.GA80355@rea.mbslab.kiae.ru>
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In-Reply-To: <xzpzn74prwm.fsf@dwp.des.no>
On Tue, Jun 15, 2004 at 09:01:13PM +0200, Dag-Erling Sm?rgrav wrote:
> I've already told you that there is no such threat, since the attack
> you describe can only be initiated by someone who already has
> unrestricted access. Please stop wasting everybody's time.
You are wrong. Unrestricted access means _really unrestricted_ and
kernel securelevel restricts access to certain places even to root.
IMHO, it's dagerous bug, because some administrators can think "...hmm,
I've enabled the hardest securelevel and even if a hacker would break
into my host with r00t privileges he will be restricted in certain ways.
The only thing he can do is to change /etc/rc.conf (for example) and
_reboot_ my host. But I will notice the reboot." So, for certain
people the following formulae may hold:
Hardest securelevel + no reboots = good security.
But this bug changes things. One can lower securelevel, do some nasty things
and raise it again _without reboots_. So, as I've already noted, you are wrong.
The bug _gives_ you almost unrestricted access.
rea
