Am I the only one that finds this highly suspicious? Bringing down XBL used to be a holy grail for DDOS script kiddies, and supposedly the new Xbox One uses a fully distributed version of XBL that's behind a global CDN (correct me if I'm wrong here). Beyond that, I'm not hearing reports of any attacks of larger-than-normal magnitude, which I would assume would be needed to take down the world's largest gaming platform.
Sounds like someone found an exploit in the Sony hack and figured out it applied to XBL as well, if you ask me. But I'm 100% not a security specialist so I wouldn't take my word for it.