Re: "The End of SSL and SSH?"

["Perry E. Metzger" <perry () PIERMONT COM>]

"Kurt Seifried" <seifried () securityportal com> writes:
> It is also incredibly difficult for users to ascertain whether the
> key is legit or not.

Generally, if a key is already in use, it is very likely
legitimate. If a key comes up as having changed, it is probably not
legitimate.

This does leave the question of how do you get keys in the first
place. In most organizations, however, systems administration is
capable of maintaining such things reasonably well. We could perhaps
make that problem a bit better with mechanisms such as on-line
key lookup (using a sort of public key version of what kerberos
provides for private key protocols), but PKI qua PKI won't improve the
situation, and in practice you can (somewhat cumbersomely) get 90% of
the benefits right now simply by being systematic about key management.

> Most users will happily accept SSL certs that
> have expired, point to the wrong site or are self signed (all of
> which could be a man in the middle attack or a lazy admin).

And yet, SSL certs are based on the X.509 PKI architecture. You claim
a PKI will fix things, but obviously it hasn't in this instance.

> I used to religously sign email's with PGP until I realized that
> no-one probably checked, how did I know this? I started modifying
> the email after signing so that it wouldn't verify, no-one ever
> complained.

I'm hardly surprised. The tools to check are hard to use and the need
is rarely obvious.

> SSH and SSL are in my opinion poor implementations of security
> protocols, they also lack a lot of things such as
> repudiation/etc. To believe they are the best we can do makes me
> very sad. I suspect in 5 years we'll talk about ssh/ssl like we talk
> about telnet right now.

I doubt it. SSH and SSL are fine protocols, but are dependent on key
management mechanisms. What you are noting is that key management is a
hard problem. Well, so it is -- but that doesn't mean that if we
change the way we do key management that SSH and SSL would go
away. The protocols themselves are fine.

In general, PKI is probably not the answer. Among other things, the
fact that it requires revocation infrastructure in the first place
gives one pause. CRLs do not work in practice.

Perry