are moving toward Mac , said Paul Henry , a forensics and security analyst at Lumension Security in Arizona . `` We all knew it was going to happen , '' he said . `` It was just a matter of time , and , personally , I think we 're going to see a lot more of it . '' The malicious software was first reported in January . It did n't gain widespread attention until recently , when Mario Ballano Barcena and Alfredo Pesoli of Symantec , maker of the popular Norton antivirus products , detailed the software in a publication called `` Virus Bulletin . '' Mac users at large , however , should not be alarmed by the incident , experts said . The program infects only computers whose users downloaded pirated versions of the Mac software iWork . The harmful software is a Trojan horse , meaning it tries to sneak into the computer with some sort of permission from the user . Computer worms travel differently . They wiggle their way into computers and replicate without the owner 's approval or knowledge . The Mac program is called a botnet because infected computers become
-LRB- CNN -RRB- -- Mac computers are known for their near-immunity to malicious computer programs that plague PCs . Some security experts say viruses are moving toward Mac as those computers become more popular . But that may be changing somewhat , according to computer security researchers . It seems that as sleek Mac computers become more popular , they 're also more sought-after targets for the authors of harmful programs . `` The bad guys generally go toward the biggest target , what will get them the biggest bang for their buck , '' said Kevin Haley , a director of security response at Symantec . Until recently , the big target always was Microsoft Windows , and Apple computers were protected by `` relative obscurity , '' he said . But blogs are buzzing this week about what two Symantec researchers have called the first harmful computer program to strike specifically at Mac . This Trojan horse program , dubbed the `` iBotnet , '' has infected only a few thousand Mac machines , but it represents a step in the evolution of malicious computer software , Haley said . The iBotnet is a sign that harmful programs