Malware on Mac prompting me to renew Norton

Skarpness wrote:

Do I need to worry about remnant processes that might run in the background?

No.

This is spam, not malware. This is advertising. Junk.

As for the general mess that exists, more than a little of the add-on anti-malware around is way too close to actual malware, too. Some of the better known stuff for Apple platforms got caught and later fined for collecting and reselling personally-identified web browsing and web purchasing data, and I’d be floored if the add-on VPNs weren't also collecting and reselling metadata. VPNs badly solve a problem that hasn’t existed for a decade or so, but doing so in a way that’s perfect for collecting, after all. The anti-malware is getting harder to distinguish from malware.

But here? This was advertising spam. Not malware.

The spam lied about the detected viruses too, because websites cannot scan your Mac. Malware scans are deeply intrusive. If a website could scan your Mac for malware, they’d not bother with the ruse and would just upload and steal your data directly.

BTW: You have built-in anti-malware tools and scanning, and built-in malware removal, within macOS, too.

The typical spam chatter involves notifications: Stop unwanted Notifications - Apple Community

Included there is how to block any future prompts for subscribing to notifications, as well.

It's just spam advertising but if you still feel insecure do a scan with malwarebytes.