Since the hack was accomplished with scripts and exploits that are available on the undernet (some at a cost), and honestly, was pretty ugly in how it was deployed, I'd have to say, no, it was not done with some secret backdoor.
But hey, here's some tinfoil anyway, just in case you need it.
6 posted on 12/18/2014 6:00:18 PM PST by kingu
(Everything starts with slashing the size and scope of the federal government.)