Apple purists continue to insist how the Mac is superior to Windows because they have not been infected by malware. In my view, this is not because of any superiority in OS X (or Unix) but rather a function of market share.
Malware is has been a for profit business since 2003, and the worldwide market share of the Mac is still under 5%. If you are trying to create a zombie network, why bother with this low return target? Apple really does have serious issues, the latest being hacked keyboards. For a list of Apple updates, see http://support.apple.com/kb/HT1222.