Re: [patch] Add basic sanity checks to the syscall execution patch

From: Pavel Machek
Date: Sun Sep 07 2008 - 08:52:56 EST


On Sat 2008-09-06 17:45:51, Ingo Molnar wrote:
>
> * Willy Tarreau <w@xxxxxx> wrote:
>
> > Then they will simply proceed like this :
> > - patch /boot/vmlinuz
> > - sync
> > - crash system
> >
> > => user says "oh crap" and presses the reset button. Patched kernel boots.
> > Game over. Patching vmlinuz for known targetted distros is even easier
> > because the attacker just has to embed binary changes for the most
> > common distro kernels.
>
> a reboot often raises attention. But yes, in terms of end user boxes,
> probably not. Anyway, my points were about transparent rootkits
> installed on a running system without anyone noticing - obviously if the
> attacker can modify the kernel image and the user does not mind a reboot
> it's game over.

Well, install a rootkit in /boot/vmlinuz, sync, then wait for user to
reboot its system?

Even well-kept servers are rebooted from time to time.

I agree -- the only way to win is not to play this game.

--
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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