Smug Mac lovers who point to Windows vulnerabilities now have something to worry about: A top security researcher claims that Windows Vista is more secure than Mac OS X.

Dino Dai Zovi recently won a $10,000 prize for hacking into a MacBook Pro, exploiting a security flaw in Apple’s Safari browser. He used the hole to open a back door and gain access to everything on the computer.

In an interview with Computerworld, Zovi said, “I have found the code quality, at least in terms of security, to be much better overall in Vista than Mac OS X 10.4. It is obvious from observing affected components in security patches that Microsoft’s Security Development Lifecycle (SDL) has resulted in fewer vulnerabilities in newly-written code.”

For years, Apple devotees have crowed that their operating system is far safer than Windows. If Zovi is to be believed, that’s no longer the case.

He’s not alone in his beliefs. Zovi won his prize at the CanSecWest security conference in Vancouver a few weeks ago, and other attendees echo his thoughts.

Dragos Ruiu, the principal organizer of security conferences including CanSecWest, told Computerworld, “I hear a lot of people bragging about how easy it is to break into Macs.”

And Theo de Raadt, OpenBSD project leader and an attendee at the conference said one reason that Mac exploits aren’t well publicized is that Apple is “extremely litigious when people do find stuff.”

I’ve long thought that one reason Apple has such a shiny reputation has nothing to do with its hardware, and everything to do with its masterful marketing. It may be that the myth of Mac security superiority is more about marketing and less about facts.