For years, many people have believed that Macs are immune to malware, viruses, and worms that have wrought havoc on PCs. In reality, however, OS X is potentially just as vulnerable to harmful programs. The difference lies in the fact that hackers generally go after what will give them the biggest bang for their buck. Traditionally, that has meant targeting PCs because they run on a more prevalent OS. Given OS X’s small market share in comparison to Windows systems, Macs are less likely than PCs to be attacked.
Since Macs are quickly gaining market share and status, however, they’re finding themselves under more frequent attacks. Apple has even alluded to this, having previously recommended that its users should get an antivirus program. For some Mac users, it may be too late, however.
Apple has been attacked by what some are calling OS X’s first official Trojan virus. The Trojan, called iBotnet, has found its way onto several thousand Macs. It does not affect Windows machines. Even though the program has reached a relatively limited number of machines, it represents a step in the evolution of malicious computer software towards Mac.
The malicious software was first reported in January, but has gained widespread attention since Mario Ballano Barcena and Alfredo Pesoli of Symantec detailed the software in a publication called "Virus Bulletin."
Experts say Mac users at large should not be alarmed by the Trojan since the program only infects computers that have pirated copies of the Mac software iWork.
This isn’t the first botnet that has been built using Mac computers, but it is interesting because it’s more flexible and has some new features. Fortunately, the potential damage that could be caused by the Mac botnet is less severe than other attacks. The botnet is perhaps most significant because it’s something other authors of malicious code can build from.
According to Gartner, Macs account for approximately 7.4% of consumer computers in the U.S. Darrell Etherington, a contributor to theAppleBlog, describes the Mac user base as more affluent than PC users. He speculates this may make Macs a bigger target as a result. Overall, Etherington notes that Macs are less vulnerable to attack than PCs.