Apple broke with a key marketing message & mdash; its Mac OS X does not have to worry about spyware and viruses — and recommended that Mac users install antivirus software.

In a short knowledge-base article published late last month, the company stated that users should install security software to safeguard their systems and make them more difficult to compromise. The company listed products from three companies: Intego, Symantec, and McAfee. Symantec is the owner of SecurityFocus.

"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," Apple stated in the article.

Previously, the company had claimed in its famous "Get a Mac" campaign that Mac OS X users do not need to worry about spyware and viruses. To date, only a handful of programs have been written to compromise computers running Mac OS X, but have relied on social engineering to fool the user into running the attacker's code. Security researchers, however, have repeatedly stated that Mac users will have to worry about malicious software when online criminals decide to write programs to infect the platform.

One researcher used concepts of game theory to estimate that attackers will not be enticed to write malicious code for the platform until Apple accounted for more than one of every six computers.

Apple focused on security in at least two of its "Get a Mac" commercials. In one, the Mac — played by Justin Long — tells the PC — played by John Hodgeman dressed in a trenchcoat, hat and fake mustache — that he does not need to hide from online thieves and attackers.

"I run Mac OS X, so I don't need to worry about your spyware and viruses," the Mac says.

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