
This sounds an awful lot like a password-guesser, not a weakness in
DES.  Merritt and I pointed out this weakness in Kerberos in a paper
that came out about 2.5 years ago, in both Computer Communications
Review and Usenix.  For that matter, it was loudly discussed on the
Kerberos mailing list even earlier.

The problem has nothing whatsoever to do with DES, and everything to do
with bad password selection.