Virus

So, on a website? As stated above it is a bogus message. Close the offending page and avoid sites that are involved in such bogus advertising tactics.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Where are you seeing this bogus message?

As stated, such messages are scams from criminals, 100% of the time, no exceptions. Do not interact with the message. Do not download anything based on such messages.

Yes, it is fake ...... 100% of the time.

You are welcome. Please read through the Apple article linked above for other information regarding scams.