Welcome to the Virus Encyclopedia of Panda Security.
Fortnight.D is a Trojan/worm that spreads extremely quickly by e-mail. To do this, it hides in the autosignature of outbound e-mail messages.
It is very easy to become infected by Fortnight.D as it can reach other computers through many different means: e-mail messages with infected attachments, computer networks, CD-ROMs, Internet downloads, FTP, floppy disks, etc.
The only sign indicating that Fortnight.D has infected a computer is the fact that some links to erotic websites are added to the browser's Favorites menu.