Wonder if someone at apple got fired, hehe.
What this is probably about is that porn site video codec. A Trojan.
It needs you to click a link, download a file, double click on it install and give your user password. So it's essentially a social engineering thing that requires the user to do quiet a lot. But it's apparently enough foe apple to tell people to install a virus scanner. Eh there is really no point though only a handful out there you'll get more trouble from the virus scanner program.

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