Computer began downloading hundreds of blobs then froze

Question

While my mother was trying to sign into her bank account, the download bar in Chrome filled up with hundreds of downloads. Her computer then froze so she restarted it and it seemed to work fine, and only 2 of the hundreds of files actually got downloaded. I looked back at the her history in Chrome and all she had open was her Gmail and Yahoo email accounts, the bank's website, and this IP address http://206.189.198.183 which she didn't open. I wasn't there when the downloads happened, but she says the page was one of those "Warning, you have a virus!" ones. I know she didn't click anything on it yet somehow the downloads all started by themselves and when she was trying to sign in to her bank account.

I also looked at the downloads in Chrome and all of those links look like this, just with different numbers and letters: blob:http://206.189.198.183/e0d7ab8b-b68a-4092-895a-15c69131bb88

I made sure she didn't click either of the two files that got downloaded and deleted them immediately.

I did a whois lookup and the IP address comes from California, but her bank is a local one in Arizona.

What can I do to secure her computer? How can I prevent fishy IP addresses like this from downloading a bunch of crap on her computer?

Answer 1

That site is employing something called Download Bomb. It just starts thousands of downloads at once to freeze the browser, scaring people with a fake virus warning. It only freezes the browser, and don't have any lasting effects or harms the computer in any way.

It's ironic that it affects Firefox, Chrome, Opera, Brave and Vivaldi, but does not affect Edge or Internet Explorer.

What to do? Press CtrlShiftEsc (or right click on the task bar and open Task Manager) and kill the browser processes. Disconnect from the network so the site cannot load its scripts, and reopen the browser. Close the affected tab and reconnect to the network.

Google and Mozilla are aware of the problem, and a fix is on the way.

Answer 2

Is she using an adblocker or pop-up blocker? Something like uBlock Origin should preempt most of the web's annoyances. Be sure to enable uBlock's extra filters, if you do decide to use it.

A connection filtering extension like uMatrix (essentially a point-and-click firewall for your browser) could be useful, though you'd most likely need to configure it for her beforehand-- the default settings tend to catastrophically break most websites.

Creating an executable whitelist could also help, in the event that she does download purportedly malicious software on to her computer again.

Finally, check to see that she hasn't installed any malicious browser plugins that would've prompted the downloads in the first place.