CACR: MacDefender shows Apple users no longer immune from cyberattacks (physorg.com)

Immune ... Ha! Apple computers where never immune. The attacks were just not as common, and still aren't, compared to Windows computers.

They say MacDefender is scareware, aka phishing, aka relying on user stupidity to enter the admin password when it asks for it. That's not vunerable, that's doing what the user told it to do.