I've just received a scamming email with an attachment that has the .js (JavaScript) file extension. On saving the file & inspecting it, the file contains heavily obfuscated JavaScript code. Fortunately I work in web development & realised that this was a threat.
I'm surprised that BD IS didn't flag a .js file email attachment as dangerous/probable virus. I think it should do this.
I've submitted the attachment as a 'false negative' via your system.
Bitdefender Internet Security 2015
Build 18.23.0.1604
Windows 7 Professional, 64-bit
Thunderbird email client 45.7.1