One problem is, the addresses used by the phishing/malware landing pages are changing every day, so Firefox's built-in bad site blocker can't keep up. Another problem is, the redirects to those sites seem to be pushed by ads on popular sites. I think developers and security people must be looking into how it's possible to distinguish a redirect coming from an ad in a page vs. the page itself, since that is a critical element of the problem and affects multiple browsers (both Firefox and Chrome users are seeing landing pages targeted to their respective browser). But cybercriminals aren't going to stop buying ads, they'll just change tactics. As part of your layered defense, you could consider using an ad blocking extension such as: https://addons.mozilla.org/firefox/addon/ublock-origin/ If you want to report a particular site as a fraud, see: [[I found a fake Firefox update]]. And if you (or someone reading this reply) did open/run the download, please try cleaning your system using Malwarebytes Anti-Malware (the free version or trial version should work the same way): https://www.malwarebytes.com/mwb-download/ You also could try some of the other tools or specialized forums in our support article: [[Troubleshoot Firefox issues caused by malware]].