Some industry sources are telling me that Sony got hacked because their IT department wasn't minding the store. Log files show repeated unauthorized intruders in their system. Had the IT department been doing its job it would have checked the logs, and clamped down on the intruders. They sat on their fannies, and it cost Sony as much as the Target hack cost Target last year.
For that matter their top execs ought to be fired for allowing a company culture of badmouthing other Hollywood figures in email.