Hacked

[Ayrehead]

I received an email from a group of professional hackers saying we gained access to your devices and we installed an exploit on your devices.

I know such emails are often hoaxes, but I have reason to believe the message may be partly true. I used antivirus software from a major company and scanned my Mac and it found zero issues. Is there something more I can do to check the Mac?

I have an iMac of 2019 vintage, intel silicon, no special security chip. Am running Sequoia which is the latest I can have.

 

[bogdanw]

It's probably just an attempt to scam you.
Install a firewall just to be sure.
Lulu is free https://objective-see.org/products/lulu.html
Little Snitch has a free trial https://obdev.at/products/littlesnitch/index.html