It’s always been claimed by Mac advocates that the lack of Mac OSX malware was not to do with the fact that malware writers were logically targeting the largest OS population, but rather was to do with the fact that OSX was inherently more secure.
It seems that with the rise in the population of OSX users, people are starting to exploit it, proving the previous assertion false.
Reading this article, this vulnerability is equivalent to the one that allowed the infamous Blaster worm on Windows to propagate – that is, a remote exploit that gives the hacker root access to deploy any code they wish to the compromised system.
My company has numbers of clients who run Mac servers that are open to the wider world sans any kind of firewall. We even have one I know of that you can get remote access to their server without a password. We've advised them that's a bad idea, but they believe their Mac will remain secure. It's a product of the misinformation by Apple that because presently there are no major threats, that the situation will continue. Hopefully, people will begin to realise that being under the radar only provides you security while you're small enough to fit there.
If you use a Mac and you're reading this - be smart. OSX is not magically all-secure. Firewalls and virus protection are good, good things.
@Nathan: I certainly wouldn't describe this post as "whiny". Maybe "gloatish"? lol.
@Frances: More mind-bent philosophy/less computer-nerdish technobable post is coming soon, I promise. :)