Below is an image of the new malware attempting to get Windows users of Firefox to install a drive-by malware labeled by Windows Defender as Trojan:Kovtar.
Valid versions of Firefox for windows are:
Stable: 47.0.1 available @ https://firefox.com
Beta: 48.0.b5 available @ https://www.mozilla.org/en-US/firefox/channel/
Nightly: 50.0.a1 available @ https://nightly.mozilla.org/
For any questions about using any or the validity of your version free free to visit:
Mozilla IRC network in channels #firefox or #sumo