I'd be worried if it weren't utter bollocks. The flashback 'virus' was written as a proof of concept 3 years ago to establish the fact that flash apps/movies make a great delivery mechanism for virus/malware, and doesn't actually do anything.
its one of the reasons apple still won't allow flash on ipads/iphones etc.
the vulnerability itself was closed 2 years ago! had a quick poke of the networks of some of my clients yesterday just on the off chance - not a sniff - thats several thousand macs at the beeb, kelloggs and several colleges
suspect there's as much in terms of mischief making here by folks trying to slow Apple's mega growth down a bit bit stirring up a bit of panic