Researchers identify malware existing in popular add-ons for Facebook, Vimeo, Instagram and others that are commonly used in browsers from Google and Microsoft. Extensions for Chrome and Edge browsers may contain malware and likely should be uninstalled. Avast Threat Intelligence discovered the malware after following up on research by Czech researcher Edvard Rejthar at CZ.NIC. The malware entered the system through localStorage, the general data repository that browsers make available to sites, researchers said. The full list of the identified extensions is here; some of them have been taken down, Avast said.
Source: https://threatpost.com/3m-users-malicious-facebook-insta-browser-add-ons/162350/