A common refrain when I post about Windows security vulnerabilities like Conficker is "Get a Mac!" thanks to their long history of being comparatively secure next to Windows PCs.

Those days may be about to change. Already this year a handful of exploits that target the Mac platform have begun to trickle out. Now comes news that one of those attacks which infect MacOS computers exclusively continues to spread and has been at least moderately successful in forming a botnet, a network of computers that come under the control of a remote attacker, usually with the goal of creating a coordinated attack on other machines (or, for example, sending spam en masse). 

The new network of infected machines is being called the iBotnet and is so far limited in its prevalence -- only a few thousand Macs are thought to be infected to date -- but as CNN notes, it's another ominous step toward the end of the Mac's free ride on the security train, as malicious hackers target the increasingly popular computing platform now that it's in use by a significant enough number of people to merit attention.

The botnet is being spread through pirated copies of the iWork application, the same mechanism I wrote about in January. But efforts to thwart the spread of the Trojan horse appear to have been stymied, as the botnet continues to rumble along. Apple says it is working to secure its machines from the attack (well of course it is...), but some are now starting to wonder whether the time is here for Mac users to consider installing security software, the kind of protection which is absolutely required on PCs these days.

Many of the Mac faithful say it's not yet mandatory, but I'm not so sure. Today's Mac malware may be relatively rare and largely innocuous, but that usually indicates that worse storms are on the horizon as hackers figure out how to take an idea and run with it. Better to protect yourself now before something truly awful makes headlines.

Should you install a Mac security application today? It might not be such a bad idea. And, some good news: at least one free anti-malware application is available for the Mac, too.