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Interesting, but I wouldn't worry about it.

Pay attention to where you download content, making sure that is reputable, should avoid anything like this.

Know what you are installing before hitting that button.
 
Good points, I have no plans to add any virus software to my Mac.
 
I should think you can safely ignore this article. What gave it away was this paragraph:-

"Clearly, Mac users - like their Windows cousins - should practice safe computing and only download software from official websites and legitimate download services,” according to Graham Cluley, an award-winning security blogger and senior technology consultant at Sophos security."

This marks it out as a typical "scare" article placed by Sphos the so-called security company who promote their products with articles such as this and aimed at uninitiated Mac users.
 
There is a certain amount of scare tactic here.
There is a certain amount of complete truth to this article
There is a certain amount of common sense required when using a computer and downloading content from anyplace online.

Just use your brain. If it doesn't feel right or something asks you for a password to install and you don't know what that something is, DON'T DO IT.
 
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