"Jihad has ethics and morals because it is for God. That means it is forbidden to kill women, children, elderly people, priests, messengers, traders and the like. Betrayal is prohibited and it is vital to keep promises and treat prisoners of war in a good way. Standing by those ethics is what distinguishes Muslims' jihad from the wars of other nations."
The CNN article indicates that it has a generic prohibition on killing "civilians", but I'm not sure if that is merely a paraphrase of the above passage (in which case it seems overbroad) or comes from elsewhere in the document.