As I understand it, all the "interesting" stuff Assange has released came directly from Russian hacking activity. Donn't forget, because of an operational procedure problem the American security files were almost a free "eat all you like" buffet. Much of what Wikileaks first posted was a collation of the myriad of files people had downloaded, stored online, etc etc. All Wikileaks did was bring them together in one place, they were responsible for finding very few of those files themselves.
The operational problem the USA had was that, because they were so paranoid about security the logon to individual stations was so involved it could take up to 20 mins to half an hour simply to access a terminal. The result was , ops left their terminals logged on 24/7 during the working week. Once you were through their "cyber front door" it took usually, less than 5 minutes to find an open terminal and away you went. It was a friend's 13 year old kid showed us how and he'd picked it up at school where it was at the time, one of the favourite pastimes amongst the computer nerds. It wasn't a few months either, it was several years that the US was almost wide open to anyone wanting to have a furtle around. The guy who was busted over the UFO files and faced extradition actually told the Yanks in real time; "Do you realise that, you have people in your system from literally all over the world, there's someone currently downloading from China?"