deception is what Snowden used to gain roles he couldn't have otherwise. It perfectly fits the definition of impersonation. By using someone else's credentials

deception is what Snowden used to gain roles he couldn't have otherwise. It perfectly fits the definition of impersonation. By using someone else's credentials he broke the separation of duty enforcement of the RBAC model, thus he could probably escalate his privileges once he had that access. The superior who gave out his credentials probably didn't comprehend RBAC and thought he was just cutting out some red tape to chase down terrorists.