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Re: Compilers make a system less secure?
- To: misc_(_at_)_openbsd_(_dot_)_org
- Subject: Re: Compilers make a system less secure?
- From: jared r r spiegel <jrrs_(_at_)_ice-nine_(_dot_)_org>
- Date: Tue, 2 May 2006 18:16:35 -0400
On Tue, May 02, 2006 at 09:49:07PM +0100, Constantine A. Murenin wrote:
> On 02/05/06, jared r r spiegel <jrrs_(_at_)_ice-nine_(_dot_)_org> wrote:
> > if we didn't have that little PIII/450 sitting next to the
> > machine now, for the purposes of bringing live, getting
> > patches onto, making .tgzs, and then copying them over to
> > untar onto host B, what bob beck criticized about would be
> > entirely accurate about me.
> One thing I didn't follow in this story is why did this 'virus' change
> the host key?
> It's not like you can't use the old key with the new sshd install, is it?
it installed its own replacement sshd and host_*_keys. had its
own config dir. didn't overwrite anything in /etc/ssh .. was
either /etc/ssh2 or /usr/local/etc/ssh2.... i don't
believe we found the src for it lying around, but here's the
stuff i did find and save from it:
( the sshd is gone, might've been some symlinks i whacked too )
$ find r00*
commandline utils ( eg: ssh-keygen ) were also suid root.
> Another thing is trusting the updated hostkey. Imagine you are a
> sysadmin at a university. Do you keep the old hostkey when you
> reinstall the system on a specific host?
in this case, no, :). the "host B" has since been replaced/installed
in situations of non-compromise, regarding the question of
hostkey-retention after reinstall/etc, i usually let the new
one ride and just give anyone appropriate a heads-up.
i've also had it in my mind to finish up a setup using SSHFP records
and a reasonably noncomplicated infrastructure to allow various
users to update the hostkeys they're responsible for ( eg
in a VPN or an environment where a team of persons have
individual primary maintainership of a variety of hosts ). that's
wicked OT tho.
> What about when you upgrade a
> Sun workstation, but keep the old hostname? How am I as a student may
> know if the new hostkey is legitimate? Good thing if I have an entry
> of another Sun workstation in the destination network in my
> .ssh/known_hosts, to which I could ssh and see if the host in question
> shows the same signature 'locally', but what if I don't?
would using a global /etc/ssh/ssh_known_hosts file (which was
under your jurisdiction) help solve that? i haven't ever used
a global one so don't know first-hand if that's its purpose.
certainly wouldn't help if the student accessed the newly-upg'd
workstation from their own desktop or whatever; but if they
hit it from some other lab workstation (or etc) instead of
from their personal machine...
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