[Beowulf] Intra-cluster security

Leif Nixon nixon at nsc.liu.se
Sun Sep 13 10:58:23 PDT 2009

Joe Landman <landman at scalableinformatics.com> writes:

> I won't fisk this, other than to note most of the exploits we have
> cleaned up for our customers, have been windows based attack vectors.
> Contrary to the implication here, the ssh-key attack vector, while a
> risk, isn't nearly as dangerous as others, in active use, out there.

I'm really hoping you aren't accusing me of security theatre.

This may be a case of differences between user communitites - while I
have seen one or maybe two cases where windows-related attacks were
involved, I have seen dozens and dozens of cases where ssh key theft was
involved. I have a blacklist of literally hundreds of stolen ssh keys
from a very large number of sites, and I dearly miss a key revocation
mechanism in ssh.

We try to educate our users to use either a good strong password or to
use ssh keys together with the ssh agent and agent forwarding, so that
the private key never needs to leave the user's personal workstation.

> Fake security, aka security theatre (c.f.
> http://en.wikipedia.org/wiki/Security_theater ) are things you get
> when people want to seem like they are doing something, even if the
> thing doesn't help, or worse, gives you a false sense of security. See
> every anti-virus/anti-phishing package out there for windows. If you
> think you are safe because you are running them, you are sadly
> mistaken.

And on our side of the fence, we get things like Trusted IRIX, with a
really elaborate, checkbox-compliant permissions system. Of course,
since it was built on IRIX, any serious attacker would cut through it
like a hot knife through molten butter, but there obviously wasn't a
checkbox for that.

                               / Swedish National Infrastructure for Computing
Leif Nixon - Security officer <  National Supercomputer Centre
                               \ Nordic Data Grid Facility

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