How do I get rid of Adobe flash update virus on Safari browser?

Thanks.

I knowingly infected Safari on my Mac with this pop-up malware.

Are you seeing pop-ups as shown in the screenshots posted below?

Force quit followed by launching Safari with the shift key down resolved the issue.

To make sure that system is clean, I ran Malwarebytes for Mac and EtreCheck.

It is possible that what you are seeing is a variant of this adware.

Download EtreCheck: https://etrecheck.com/  and post the report here.

      Click, “Free Download” button and then  “Click to download” button,

      open Downloads folder, click on it to open, and then select ”Open”.

      “Choose a problem” from the popup menu box, and then “Start EtreCheck” in the dialog.

      Click “Share Report” button in the toolbar and select “Copy report”.

      Click the “Page” button in the toolbar at the bottom of this page and paste it when you reply.

      Note: This is a diagnostic test. 

I strongly counsel against disabling Flash updates.

Flash has had many security vulnerabilities over the years.

Disabling updates for an app that run untrusted, remotely-loaded apps is precarious.

If patches are inappropriate and for whatever reason, best to remove Flash altogether.

And this case does not appear to be Flash itself given the OP’s initial update checks, but rather malware.

Make sure you have a complete and current backup. This in general, and given this is an old hard disk.

Remove the two add-on anti-virus apps per the vendor's’ instructions, reboot, and try again.

You’re short on physical memory, and this hard disk looks like it might be headed for hardware problems.

Remove Java, unless you’re using that.

I’d likely remove Google apps, as those have a habit of being resource-intensive.

Remove Flash, unless you’re using that.

Remove Microsoft Silverlight.

There’s some truly ancient software on this Mac, too. That Easy-WebPrint app is a decade old.

Upgrade Paragon, or remove it.

Check for browser plug-ins, too.

Looking at what’s loaded here, I’d be inclined to back up, wipe, install High Sierra again, and load new copies of the necessary apps. And a RAM upgrade, and an SSD, if you want to try to get a few more years.

Your upgrade issues were quite probably all the odd and the old bits here, and the add-on security bits. Which is why I suggested the path I did. Wipe, install, migrate files and docs, and load just the needed apps. Add-on anti-malware has a long history of causing problems. There’s comparatively little Mac “virus” malware around. Most of the malware—there’s a fair amount of it—is stuff that the user intentionally installs, and which means the anti-malware really can’t easily tell if it’s a feature that the user wants and needs, or if it’s junk... `The Apple anti-malware does a decent job with the most pernicious junk that’s around, too.

Some of those pop-ups are just straight up website scam postings. Web sites you visit, with themselves or their advertisers trying to get you to load malware.

As for your configuration, Adobe Flash, Silverlight, both add-on anti-virus apps, Java, Google, and the old Paragon NTFS have all been removed, and you are still getting not-website-ads pop-ups?

You’ve probably also flush Safari cookies and apps, and remove extensions?

If so... Enable full drive access in EtreCheck and then post another report, as that’ll be able to show more:

https://www.etrecheck.com/faq

Remove Flash, and see what (if anything) breaks. If there’s no Flash installed, you know any Flash references are scams.

Adobe is retiring Flash, and Flash has never existed on iPad and iPhone, and no large websites require it. A few games, yes. For the rest of us, no.

Java is not JavaScript.

I’ll leave this to somebody else, as you seem intent on your own approach, and your own path.

Please gather and post an updated EtreCheck report, and consider the possibility the network equipment you are using (specifically, its router) has been subjected to malicious tampering.

The way to recover from that is to reset its hardware and reconfigure it.

Reset Safari's history and website data (again).

Full drive access: Disabled

Please enable that feature (assuming that's an option for its free version—refer to its instructions, because I don't know) and capture another report.

And don't forget to clear Safari's history and website data:

Clear your browsing history in Safari on Mac - Apple Support

Manage cookies and website data in Safari on Mac - Apple ...

Etrecheck is in the App Store.

https://apps.apple.com/app/etrecheck/id1423715984?ls=1&mt=12