CUPERTINO, CA — It’s not the first time that Mac users have been reminded that they aren’t impervious to harm but, according to CNET, it is the most recent time that the message has been conveyed: Install antivirus software even if you own an Apple computer. As Security blogger Elinor Mills explains, Apple’s operating systems haven’t suddenly become less stable, they’ve simply become more popular – and therefore, more appealing to walware creators.

With an ever-increasing number of computer users going online, where both genuine and disguised downloads tantalize, Apple has one again reminded its fans via its Support website that it “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.”

Three software recommendations are made, with Intego VirusBarrier X5, Symantec Norton Anti-Virus 11, and McAfee VirusScan for Mac earning praise.

While Apple has never specifically claimed to be ironclad against attacks, its users and some of its television ads have certainly emphasized the infrequency with which malware has targeted Apple systems. Retail clerks have been known to assure new buyers that antiviral programs are an unnecessary protective luxury – but that honeymoon period may well be coming to an end.

“Apple is realizing that malware these days is targeting data, and valuable data exists just as much on an OS platform that is a Mac as it does on an OS platform that is Windows,” director of security research and communications at McAffee, Dave Marcus, is quoted as saying on Mills’ blog.

Backing up Marcus’ observation is the fact that Trojans and other Web-originated malware is finding its way onto Apple systems – as are application-specific wares that are more interested in app vulnerabilities than the systems supporting them.

According to Marcus, one of the biggest offenders today are the “password-stealing Trojans,” that affix themselves to apps and then “are dropped onto the machine to do something. They don’t infect files and copy themselves. They are looking for specific information and they send that information somewhere else.”

Windows machines remain the most popular targets for Trojans and various other forms of attack ware, with Office and Internet Explorer still leading the pack, but Macs are increasingly gaining attention. Last year one Mac-focused Trojan targeted porn fans while this summer saw the introduction of “AppleScript.THT.”

Installing and running an antiviral program is always advised, regardless of what operating system one runs, although there are differing opinions about the value of employing multiple products on one computer, since they often jockey for limited system resources and can cause software conflicts.