This attack doesn't look like a big deal, unless you run, and naively fall victim, to the malicious codec. Just like MacScweeper, Imunizator tries to frighten Web users into believing they have a problem, or infection, on their system. Of course, by downloading, and running the software your problems will be solved. Yeah, right.
In fact, they're probably just beginning. At best, these applications get people to pay for software that doesn't do anything; at their worst, they plant snoopware on user systems. Trend Micro says that the attack looks very similar to a Windows-based attack, Zlob/MediaCodec -- which was "ported" to the Mac platform.
These attacks are money makers, for sure.
While there doesn't seem to be anything new to the Imunizator attack, it does show increased attention being paid toward attacking Mac users.