Talk about muddying an issue.

For years most Mac users have proudly refused to buy and use third-party antivirus software, leaving that hassle to Windows users.

While security experts sometimes have criticized this attitude as irresponsible and risky, Mac users had several good reasons to ignore antivirus protection.

One reason is that OS X’s Unix foundation makes it difficult, if not impossible, for a virus to surreptitiously install itself on a Mac. A better reason is that as of today, some seven years after Mac OS X debuted, there are still zero viruses for it.

This view – that Macs don’t need antivirus software – took a sudden hit when Washington Post tech blogger Brian Krebs noted last week that Apple in fact had a KnowledgeBase article on its Web site recommending that Mac users install antivirus software.

Security experts declared themselves vindicated. Apple haters gloated. Mac users began to fret.

The very next day, Apple pulled the KB article, with Apple spokesman Bill Evans explaining to Computerworld that it was “old and inaccurate.”

Now here’s where things start to get cloudy. Evans continued: “The Mac is designed with built-in technologies that provide protection against malicious software and security threats right out of the box. However, since no system can be 100% immune from every threat, running antivirus software may offer additional protection.”

So apparently Evans is saying Mac users have no need for antivirus software, but should run it anyway just in case they do. Ack!

And what about that “old and inaccurate” article Apple yanked? Here’s what it said:
“Apple encourages the widespread use of multiple antivirus utilities so that virus programmers have more than one application to circumvent, thus making the whole virus-writing process more difficult.”

This “old” article was posted in 2007 and updated in 2008, so Apple can’t say it was referring to the Classic Mac OS of the 1990s. If that article is “inaccurate” now, surely it was inaccurate in 2007.

Or does it mean Apple’s 11 new security features in Leopard made that big of a difference? Because if that’s true, Apple should issue a warning to the Mac community of the risks of using earlier versions of Mac OS X.
Why the mixed signals? Cynics on the Web have theorized Apple pulled the KB article as a PR move; it was embarrassed that the public had discovered its recommendation to use antivirus software even as its advertising touted Macs as a virus-free paradise. I’m inclined to agree.

Evans’ widely quoted statement clarified little, since he comes close to contradicting the party line when he says no system is immune from all threats and suggests Mac users install antivirus software – just as the withdrawn KB article did.

With Apple leaving its customers befuddled over what they should do, it fell to tech Web sites to dispense recommendations.

It’s been said before, but it always bears repeating: while Mac users have little to fear from the sort of self-propagating viruses that plague Windows PCs, they still need to be wary of other cyberthreats.

The biggest comes from phishing schemes – attempts to fool people into divulging their passwords or credit card information. Most of these come in the form of fake e-mails from banks or retailers. The e-mails link to phony Web sites, so it doesn’t matter whether you use a Mac or Windows.

And although no viruses exist for Mac OS X, several Trojan horses lurk out there. But this variant of malware also relies on user gullibility. One usually needs to visit a shady Web site (like a porn site), where the user gets a message that they need some sort of plug-in to view the, uh, material.

Instead of downloading a plug-in, however, clicking on the link downloads the malware. Even then the user must still type in an administrator password to install it, but at that point the urgency of the moment probably has caused the desertion of all reason.

Skeptics will continue to scoff at Mac users who refuse to bow to the tyranny of the security fearmongers. But until a credible threat surfaces that requires the use of antivirus software on a Mac, I expect few Mac users will bother with it.

PS: If you’re still feeling a bit paranoid but don’t want to shell out the money to Symantec, Intego or McAfee, check out the free ClamXavMac antivirus software.