AFS and tokenforwarding

[Nicolas Williams]

On Thu, Oct 04, 2001 at 06:58:24PM +0100, Simon Wilkinson wrote:
> > If the token is forwarded before authentication then you don't know if
> > the server is really who you think it is, so you might be forwarding
> > your token to an impostor. Ooops.
> 
> But, assuming this is a Kerberos token you are discussing, is the
> token not protected by being encrypted with the session key, which in
> turn is encrypted with the server's host key?

Yes, but if the token is not going to be useful until after [Kerberos]
authentication then why bother sending it early?

> So, an imposter could get something to brute force, but they could get
> that via a passive attack anyway.
> 
> I would agree however, that forwarding a TGT _before_ the users credentials
> have been accepted seems theoretically wrong, however practically safe it
> may be.
> 
> Cheers,
> 
> Simon.


Nico
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