No, it is not legitimate. What you see is only an animation and not a real scan. Anyway .exe files only run on the Windows platform and not on Mac or Linux.

You can use Help > Report Web Forgery to report such a site if you encounter one.

Thanks for the quick reply. The pop up is incredibly well done and rips off the Firefox brand "look" so I reported it as a trademark violation. Didn't know about the .exe files .... Apple newbie