Has anyone encountered this issue? If yes, then how to deal with it (details inside)?

I’m using Window 8.1. I tried to access Google using Firefox, but when I went to www.google.com, I got a plain message saying: “WARNING! Your Flash Player may be out of date. Please update to continue.” I clicked OK and was redirected to a webpage seemingly of Adobe. I clicked on Install and the Internet Download Manager download screen appeared like normal (I use Internet Download Manager to download). The installation proceeded normally, but when I viewed the downloaded file it was nothing like a Flash Player installation file. It was just a program with a suspicious apple icon.

I think it was some kind of scam. But any attempt of mine to get to Google was useless. My Google Chrome suffered from the same issue too.

What is happening? What should I do to deal with this issue?