Google starts to give more control to users over extension installations in Chrome browser as they decided enough! not to allow extensions installed by third party programs on Windows from Chrome v25 onwards. Till now Chrome allowed third party programs from installing extensions into the browser using Windows registry mechanism for adding useful extensions by Windows applications.
Product manager of Chrome says “Unfortunately, this feature has been widely abused by third parties to silently install extensions into Chrome without proper acknowledgment from users.“
Chrome to automatically disable extensions installed by Windows Applications
Chrome already not allowing extension installations not hosted on Chrome web store and now extended it to Windows applications as well. From Chrome version 25 onwards if any Windows app tries to install an extension silently into the browser then Chrome alerts user by showing badge on menu which when clicked shows UI dialog (check the screenshot below), when user explicitly gives the permission then only extension will be installed if not will be disabled by default.
Chrome follows Firefox in extension blocking
If some extensions already installed in this fashion, Google not leaving them either -Chrome scans for all external extensions installed by programs and disables them automatically, but user will be shown one-time prompt to re-enable any of extensions which is much similar to what Firefox doing now.