What does malware mean on Firefox?

Malware is short for "Malicious Software". It is a term generally used for software installed on your computer that is designed to infiltrate or damage a computer system without the owner's informed consent. Sometimes a problem with Firefox may be a result of malware installed on your computer, which you may not be aware of.

What does a fake Firefox update notice look like?

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:

Do I need a Firefox update?

An update is required to stay secure and an Update Now button, this is a legitimate Firefox update notice and you should update Firefox. To learn more about the "Heartbeat" feature, see the article Rate your Firefox experience, surveys and out of date messages (Heartbeat) and this Mozilla Wiki page.

How do I stop Firefox from getting a virus?

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 What happened to Tracking Protection? (enabled in Private Browsing by default).