The Trojan, being called "iWorkServices" or "iServices", has been distributed via BitTorrent inside a pirated version of Apple's new iWork '09 suite.
Hackers have used a pirated version of iWork '09 as a "host" for the malware, just as Apple has loosened up anti-piracy protection in the package.
While previous versions of Apple iWork required users to enter a serial number when installing from CD ROM, the new version allows users to install the software on as many computers as they like - without apparent repercussion.
Malware affecting Apple Macs is much less frequently encountered than it is by Windows-using counterparts.
