Russian security firm Dr. Web reports that the Flashback malware has found a home in the Mac OS X 10.6 Snow Leopard. The anti-virus specialist and discoverer of the currently active Flashback variant has recorded and evaluated the botnet's communications.

Computers running the predecessor to 10.7 Lion, 10.6 Snow Leopard are the most infected. Approximately 63% of infected Mac's run Snow Leopard, another quarter use Mac OS X 10.5 Leopard and only 11% of infected systems with the Flashback botnet are unpatched Lion machines.

Leopard users are out of luck for protection against this botnet since Apple only provides security updates for Snow Leopard and Lion. Even worse, the Flashback malware removal tool only works under Mac OS X 10.7

One of the likely reasons why significantly fewer Lion systems are affected is that Java is no longer a default component of the latest Mac operating system and must be installed manually. Apple's future plan is to completely abandon its own Java development and leave it to Oracle, which published its first sponsored Java release for Mac OS X last week.