Did Apple give us the last update to block Backdoor.OSX.Mokes.a? I read that it has installed on PCs and Linux in the past, and now an OS X version is showing up.
There are some third party anti-malware tools that have added it to their definitions. I used the hash (as reported by the researcher who discovered the Mac variant) at virustotal.
I've not read anything so far that explains its infection vector.