Less than an hour after the last misdelivery notice arrived, I changed my iCloud password, and although there were a number of misunderstandings between Apple and me over the course of the next few hours, I note that no further "Delivery Notification: Delivery has failed" messages landed in my inbox following my first password change. This suggests either that the Russian assholes were spoofing my return address for just a couple of hours on Monday and then inexplicably left off, or that something changed that rendered my electronic addy unavailable. Since the password change was the principal change in the environment during taht narrow window, I'm inclined to think that this was the vulnerability that was exploited. Govno!

cordially,