Hardening BSD is definitely trickier than hardening a Linux based workstation being that the top 3 distributions of BSD, Net, Open, Free, have done an excellent job of strengthening the systems on their own. Using FreeBSD at home while I write this, I'll try to focus in on it, but in general (and I may get flamed from the OpenBSD advocates or even NetBSD advocates) you could follow suit between the three. (Dare I say it)
FreeBSD does its daily audit via way of /etc/periodic/daily/$SCRIPTS which are run to ensure some integrity is met on the machines however after installing third party programs, you're going to lose some of the integrity you could otherwise expect on a default install.
News: Server Security
