I found a fake Firefox update
We have received reports from many users who were interrupted in their browsing experience and who got redirected to a fake page purporting to provide an "urgent" or "critical" update and prompting to download a firefox-patch.js (or .exe) file. Some people have also reported seeing ads prompting them to download a Firefox update. More recently, there have been occurrences of fake Firefox requires a manual update pages that try to trick people into installing a malicious extension.These are scam tactics trying to trick you into installing malware!
Firefox has an automated background update mechanism which will never prompt you to manually download and execute a file, except in the case of a Heartbeat notification (as shown above). You can always check for updates within Firefox yourself - to learn how, see Update Firefox to the latest version.
To our knowledge, fake update notices are a form of "malvertising". Those fake notices get triggered by code contained in ads that are displayed on otherwise legitimate websites you are visiting and get spread through advertisement networks. This is an example of what a fake Firefox update notice might look like - these are hosted on randomly generated and quickly changing domains:
What you can do if you spot a fake update notice?
- Always click Cancel on these pop-ups. Never save and open/run unsolicited files!
- Install an ad-blocking addon from addons.mozilla.org to avoid such kind of malvertising in the future.
- Report web forgeries to the Google Web Forgery site.
What you can do to prevent malware on your computer
- Run a malware scan on your computer to make sure your computer was not infected. (See Troubleshoot Firefox issues caused by malware.)
- Avoid downloads from unreliable sources in the future.
- Use Tracking Protection (available as a Test Pilot experiment or in Private Browsing).
To learn more about malware
Fake updates have been spotted for other popular browsers. Although we cannot root out every bad actor on the web, we are continuing to improve Firefox's defenses against malware. Knowing how to recognize and report such frauds helps us keep the Internet open and safer.