Multiple news outlets [ZDNet, CBC, The Register and Washington Post] are reporting on what appears to be the first malicious botnet made up only of machine’s running Apple’s Mac operating system.
The botnet is directly linked to a previously known Trojan that was embedded into pirated copies of Apple’s iWorks program. It was being used in the past to launch denial-of-service attacks. The full analysis of the botnet is available at Virus Bulletin [subscription required]