This is a theoretical exploit which involves brute forcing the NCK from the seczone the CHIPID and the NORID. So far no one has made public an instance of NCK discovery using this theoretical approach.
Given that NCKs are 15 digits long, the keyspace is 1015 (about 250). This would be searchable if all the cryptography used was symmetric. But the algorithm is TEA(RSA(token),NCK+CHIPID+NORID) TEA. So that inside RSA has to be done. A modern machine can search the 8 digit keyspace in about 5 minutes, which means we need a couple orders of magnitude speed increase to consider 15 digit.
Multithreaded NCK Brute Forcer Archived 2011-03-17 at the Wayback Machine discussion and link to download.