Re: FW: CISCO PIX Vulnerability

[Rick Smith <rick_smith () securecomputing com>]

At 09:12 AM 6/18/98 -0400, Perry E. Metzger wrote:

> You should remember that we made DES mandatory only for
> interoperability reasons, and that the decision was made years ago. If 
> we were doing it again today, I suspect that we would have made 3DES
> mandatory instead.

I think we all realize *why* there are products with short keys. But the
point for users is that *most* of their choices involve short keys, so
that's what lots and lots of them are going to use. We need to provide
sensible guidance in using such products, instead of simply blowing off the
majority of products available. People are going to use them anyway, so we
might as well get used to talking about them.

> > On the other hand, there are NO reports of a criminal or
> > competitor having ever mounted a brute force cracking attack on a
> > commercial enterprise and caused it real damage.
>
> It is likely that you wouldn't hear about it if it happened.

Disagree. If such attacks cause financially significant damage in a number
of enterprises, then the results *will* become public. If the attacks are
relatively insignificant (i.e. they can be hidden by all victims) then they
must be relatively insignificant as security threats go.

Remember: I'm *not* saying that key length is irrelevant, I'm saying that
it's only one of many parameters. For many types of information, brute
force decryption is *not* going to represent the biggest threat to an
enterprise. Cracking a single randomly chosen message isn't going to be
worth the effort to an attacker unless all messages contain something
valuable, like a reusable secret password.

Rick.
smith () securecomputing com