Microsoft made a big deal about Windows NT getting a C2 security rating. They were much less forthcoming with the fact that this rating only applied if the computer was not attached to a network and had no network card, and had its floppy drive epoxied shut, and was running on a Compaq 386. Solaris's C2 rating was just as silly.

Secrets and Lies: Digital Security in a Networked World (ed. 2011)