Researchers say 500 Google Chrome browser extensions were part of a massive malvertising campaign. Malvertising often is used as a vehicle for fraudulent activity, including data exfiltration, phishing or ad fraud. The extensions, all of which have now been removed, were downloaded millions of times from Google s Chrome Web Store. The extension would connect browser clients to a command-and-control server and then exfiltrate private browsing data without the users knowledge. Google has implemented new user data privacy policy guidelines, requiring extensions handle user data to have a privacy policy.
Source: https://threatpost.com/500-malicious-chrome-extensions-millions/152918/