I'm trying to remember how many times I've seen this same article over the past two years. It's obvious people at InfoWorld don't know much about Macs. First, the only way that hackers will exploit a Mac is if the Mac user is an idiot, and most Mac users are NOT idiots (most of the intellectual world uses a Mac). Second, IT departments that run Macs (like the U of Mich) run Radmind, which definitely ALLOWS AN IT DEPARTMENT TO UPDATE SEVERAL MACS AT ONCE.
The PC world just can't stop the Mac hatred...so they're trying to plant the myth that Macs are now at risk. Yes...they've always been at risk (like any system), but I still say that any UNIX-based system is far more secure than Windows.