Mac Rumors is reporting that the first virus targeting Mac OS X has been spotted in the wild. The site is careful to classify the virus as a trojan because it doesn't exploit any hole in the OS but instead tricks the victim into executing it. The trojan spreads by masquerading as an archive called "latestpics.tgz" containing screenshots of OS X 10.5 Leopard. The archive contains files that present themselves with a standards JPEG icon but is in fact are executable, and when opened infects other executable files on the machine. Once executed, the trojan spreads itself via iChat. Sophos has named the virus "OSX/Leap-A" and given it a low prevalence rating.