If you use Google’s web browser Chrome, and you’ve noticed that some extensions are causing problems, take heart. Google recently discovered that about 200 Chrome extensions are injecting ads in deceptive ways, often leading users to malware. These extensions have been killed by Google, and measures taken to prevent this type of abuse in the future. Note that Google doesn’t explicitly bar ad-injection extensions; however, such extensions are subject to certain limitations.
If you suspect that your installation of Chrome is running one or more of these rogue extensions, your best bet is to uninstall Chrome completely and reinstall it.
Update 2015Apr09: Google’s efforts to identify and remove problematic extensions are ongoing. More announcements of this type are expected. For example: the extension ‘Webpage Screenshot’ was found to be collecting user data inappropriately, and was also killed.