Is there currently a Firefox attack that claims it's fixing a network security issue?

It’s happened twice in the past week. I suddenly get redirected to a almost blank screen claiming a possible security intrusion was detected. Then this dramatic bar graph showing scanning progress. Then finally it offers a Firefox “security” patch. I exit my browser and clear my cache ASAP. Scares the absolute crap out of me.

My bullshit meter is off the scale on this one. Firefox automatically updates itself all the time. Why would they suddenly go for the dramatics of a bar graph showing “a security scan’s” progress? That’s 15 years out of date programming. Modern software doesn’t show bar graphs while updating or scanning anymore.

Is it a hack or not?

That sounds hugely suspicious. I would suggest you run a check with Malwarebytes or similar and check that all your add-ins like Flash and Java are up to date.

I had something similar last week but in Chrome. While navigating within a page I use often I was suddenly confronted with several windows warning of attempts to infect my PC and networks and steal passwords. I shut down everything with task manager and scanned the PC but found nothing. However I couldn’t get Chrome to reopen. Not from the task bar, the desktop or the folder. So I switched everything off, rebooted, had no luck again and deleted Chrome and did a fresh install. All has been normal since.

Prior to the incident I think I had done all my usual malware, virus and tuning stuff either one or two days before.

I have the registered version of Malware Bytes and its detected and blocked bad ads several times. I’ve also had entire sites blocked with a Whoa! Do you really want to go there? screen.

But it didn’t detect anything in this situation with Firefox.

Sounds like an obvious scam website to me.
Nothing having to do with any installed malware - this is how they get you to install it!