Oh this fake firefox-patch.js scam is very well known as you can see at https://support.mozilla.org/en-US/forums/contributors/712056 and https://support.mozilla.org/en-US/forums/contributors/712075 Its good that you recognize it is fake. The Firefox updates are done internally in Firefox (with a .mar type of file) whether on Windows, Mac OSX or Linux or by download from mozilla.org like say www.mozilla.org/firefox/all/ btw Firefox '''48.0''' has been the current Release since Aug 2nd as you appear to be using 47.0.1 https://www.mozilla.org/firefox/48.0/releasenotes/ You could try using a adblocker extension like uBlock Origin to block theses fake ads if you keep getting them. https://addons.mozilla.org/firefox/addon/ublock-origin/