The misbehaving Firefox add-ons were misusing an API that controls how Firefox connects to the internet.
Mozilla’s Firefox team has blocked add-ons that were abusing the proxy API in order to prevent around 455,000 users from updating their browsers.
In a Monday post, Mozilla’s development team members Rachel Tublitz and Stuart Colville said that they’d discovered the misbehaving add-ons in early June. The add-ons were misusing the proxy API, which APIs use to control how Firefox connects to the internet.
Add-ons are powerful snippets of software that can be added to Firefox or other apps to customize the browser by doing things like preventing tracking, blocking ads, downloading videos from websites or providing content translation.
On the flip side, they can be nasty little critters that install malware, like the 28 add-ons for Facebook, Vimeo, Instagram and others that researchers found in commonly used browsers from Google and Microsoft last year. The add-ons were siphoning off sensitive data, had the ability to enable further malware downloads, and were tweaking links that victims clicked on in order to redirect them to phishing sites and ads.
The Firefox team said that the misbehaving Firefox add-ons they found