We've all gotten some variant of this email before, even legitimate ones. A package can't be delivered. Maybe they couldn't get access to a building; maybe the address was typed incorrectly.
This attack, which does a fairly good job of spoofing FedEx, claims that FedEx couldn't deliver your package, because the delivery address was wrong.
In order to remedy this, they want you to fill in some information on an attachment. This attachment is actually fairly common and it is indeed malicious.
