Anybody else got spam from "postmaster@hotmail.com"?

This message must be spam. It looks like a typical failure notification message and comes from “postmaster@hotmail.com” but the original message is not something I sent from my hotmail any time recently (ie within the last decade). The content itself is clearly spam and the attachments could easily be viruses.

My actual question is: how can these people have an email account with that name? Aren’t names like “postmaster” already taken or blocked by Microsoft? Are they using some sort of mask on the name, or is it some back door they’ve discovered? Seems pretty malicious.

Also, is there someone I could inform of this? I’ve got my eyes open about such threats, and even I was almost fooled. So it seems pretty tricky.