Replaying and server side caching.

[Matt Crawford]

> > darrenr> If the attacker can re-use a TGT request that has
> > darrenr> already been sent to cause a valid TGT response to come
> > darrenr> back, then the attacker can gain access where perhaps
> > darrenr> they previously could not.
> > 
> > The TGT response won't do an attacker much good without the session
> > key.
> 
> Except that an AS-REP is encrypted in the user's long-term key,
> which allows for an offline dictionary attack.

Except that it's an unusual network state that lets the attacker
eavesdrop the request (to replay it) but not the original reply.