From the article:

Users of Apple Computer Inc.’s Macintosh computers have long enjoyed the technology equivalent of a safe neighborhood, where the viruses and security nuisances that bedevil far-more-common Windows-based PCs are practically nonexistent. Now, as the Mac is seeing some of its best sales in years, bad guys appear to be casing the joint.

In the past two weeks, information-security companies such as Inc., Sophos PLC and McAfee Inc. have identified several security issues related to the latest version of Apple’s Mac operating system, called OS X. Among the concerns: two ”worms,” programs written by unknown people that were designed to spread themselves to other Macs through Apple’s iChat instant-messaging software and Bluetooth wireless-communications capability.
And in a reminder that Macs, like Corp.’s Windows software, also contain worrisome security holes, a German graduate student last week discovered a vulnerability in OS X that could let a hacker install potentially damaging code on a Mac through the Safari Web browser.

Read Macintosh reputation for safety shaken with two worm attacks