Yes, Directory Naming Service needs security.
Oh, my, in this modern, Internet-enabled age DNS security is a larger and larger concern every man-hour. DNS Spoofing, DNS Poisoning, DNS Highjacking, just to buzzword out a few scary key words, are all issues that need to be addressed. And, once again, TechRepublic has an article on it. This time, though, it's a download: Ten Things You Should Know About Securing DNS. Granted, this is a pretty esoteric topic, but, then again, you're at the Diary of a Network Geek, where Alpha Geeks come to sniff each other's... Er, I think I've gone one metaphor too far with that one! Besides, with a name like that, did you expect something simple and user-friendly? No, gentle readers, not here. Nothing but the most difficult and challenging questions and issues. (Coming soon: Geek Dating!)
Anyway, best to read the article before someone starts calling your website names.
Take some advice from your Uncle Jim, computer security is nothing to ignore!