I had the same (?) issue last night. Popups over and over again but it wasn’t related to any one website. I did not have the Play Store open at the time and it seemed to recur when I did a search from the search bar. It happened in Chrome, Firefox, and Safari.

http://imgur.com/MefjfFt.png

http://imgur.com/6JjBB7a.png

I deleted Firefox and Chrome as well as related files in Application Support. The popups stopped in Chrome and Firefox but continued in Safari for a while. They all stopped at a seemingly random time when I was away from the computer for a moment.

After reinstalling Firefox, I get this error. I do not get this in Chrome or Safari. I’m not sure if they are less secure or if the Web Shield isn’t running in those any longer or what.

http://imgur.com/UpdesI4.png

Here are the details.

http://imgur.com/ZD2l96j.png

I downloaded MalwareBytes Anti-Malware and the scan came up clean. I followed all of the steps that applied to me on this page. The only thing I didn’t do is try a new network since that wasn’t practical last night. Now the popups have stopped so I don’t know if that would tell me anything.
https://support.malwarebytes.com/customer/portal/articles/2045704-what-should-i-do-if-malwarebytes-anti-malware-for-mac-didn-t-solve-my-problem-?b_id=9511

I ran a scan on Avast, which found two infections in old install files. I deleted those but the popups stopped before I deleted these files.

http://imgur.com/NuQ0e5G.png

I also scanned the network, which appears OK and my roommate doesn’t seem to be having a problem.

I searched for “blacklisted url blocking (URL:Mal)” but I don’t think that quite applies (but I could be wrong – I’m not a security expert). So now my questions are:

  1. How do I make Firefox usable?
  2. Am I safe using Safari and Chrome in the meantime?
  3. What the hell happened last night and are there further steps I need to take to make sure I am safe?