What can I do after detected under mirai malware attack

Be sure to not do anything, do not download anything.

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

//support.apple.com/en-us/HT204759

Safari browser can have history wiped and quit; a browser get faked-out

and may need force-quit. Sometimes these frauds can get out of hand.

But mostly the problem happens, in how you deal with phony scams.

• Phony "tech support" / "ransomware" popups and web pages - Apple Community

//discussions.apple.com/docs/DOC-8071

• How to install adware - Apple Community

//discussions.apple.com/docs/DOC-7471

There are other instructive Apple support sites; and a few good user tips.

Malwarebytes for Mac (14-day trial) ~ free download:

https://www.malwarebytes.com/mac-download

• Protecting against malware in macOS - Apple Support

//support.apple.com/guide/security/protecting-against-malware-sec469d47bd8/web