Security News > 2021 > October > Mozilla blocks malicious add-ons installed by 455K Firefox users
Mozilla blocked malicious Firefox add-ons installed by roughly 455,000 users after discovering in early June that they were abusing the proxy API to block Firefox updates.
"Starting with Firefox 91.1, Firefox now includes changes to fall back to direct connections when Firefox makes an important request via a proxy configuration that fails."
To block similar malicious add-ons to abuse the same API, Mozilla has added a system add-on dubbed Proxy Failover.
Mozilla advises users to update their web browsers to at least the latest release version, which can make sure that they're protected from add-ons abusing the proxy API. "It is always a good idea to keep Firefox up to date, and if you're using Windows to make sure Microsoft Defender is running. Together, Firefox 93 and Defender will make sure you're protected from this issue," Tublitz and Colville added.
To make sure, try to update Firefox to the latest versions since it bundles an updated blocklist designed to disable these malicious add-ons automatically.
If you want to ensure that there are no traces left, you can also refresh Firefox to reset all add-ons and settings or start from scratch by downloading and installing a new copy of Firefox.