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Firefox Blocks Malicious Add-Ons Misusing Its API

Update includes a system add-on for further protection

By Joshua Hawkins Joshua Hawkins Freelance Technology Reporter Full Sail University Josh Hawkins is a freelance writer for Lifewire who loves writing about the latest tech and gadgets that help make people’s lives easier. As an avid gamer and VR enthusiast, he also enjoys diving deep into the technology that helps bring those kinds of experiences to life. lifewire's editorial guidelines Published on October 26, 2021 12:47PM EDT Fact checked by Rich Scherr Fact checked by Rich Scherr University of Maryland Baltimore County Rich Scherr is a seasoned technology and financial journalist who spent nearly two decades as the editor of Potomac and Bay Area Tech Wire. lifewire's fact checking process Tweet Share Email Tweet Share Email Internet & Security Mobile Phones Internet & Security Computers & Tablets Smart Life Home Theater & Entertainment Software & Apps Social Media Streaming Gaming Mozilla has shared information detailing the discovery and removal of several browser add-ons that misused the proxy API built into Firefox. On Monday, a new post from Mozilla revealed the blocking and removal of multiple add-ons used by 455,000 users. The development team first found the add-ons in June, and Mozilla says that when installed, they would misuse the proxy API that controls how Firefox connects to the internet. It could then stop users from updating their browser, which would keep them from getting access to important changes, blocklist updates, and more. Mozilla Now that Mozilla has blocked the add-ons, it also is taking additional steps to mitigate this issue in the future. Starting with the most recent Firefox version 91.1, the browser will include changes to fall back to direct connections whenever it makes an important request. These requests include looking for significant updates, as well as downloading changes to the blocklist. If the proxy configuration fails, Firefox will move to a direct connection to ensure that users still get the latest downloads and protection. Mozilla also has deployed a new system add-on called Proxy Failover, which will be shipped with current and older versions of Firefox. Mozilla Mozilla recommends that users download the latest version of Firefox, version 93, as well as ensure Microsoft Defender is running to help keep your computer safe. Users who need to update should try downloading the update. If it doesn’t work, Mozilla says that you’ll need to follow a series of steps to unblock the proxy issues caused by the affected add-ons. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire How Do I Update Firefox? (Most Recent: Firefox 106) How to Fix the 'Internet Explorer Has Stopped Working' Error How to Use Firefox for Mac 8 Best Free Download Managers (Updated October 2022) How to Use Firefox's Privacy and Security Features How to Turn off Incognito Mode How to Turn on Incognito Mode in Your Browser How to Selectively Disable Internet Explorer Add-ons How to Disable JavaScript in Firefox How to Delete Cookies in Every Major Browser How to Prevent Firefox From Using Too Much Memory Firefox Quantum vs. Google Chrome How to Delete Your Firefox Account Managing Add-Ons in Internet Explorer 11 How to Enable and Allow Cookies on Mac How to Secure Your Firefox Browser Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies