There are several reports out this morning regarding the leak of a preliminary report generated by the House Committee on Standards of Official Conduct, aka the Ethics Committee. See the report on the NPR site here, and on the NYTimes site here.
Although one representative deemed this to be "cyber-hacking" it appears, instead, to be a simple case of a staffer releasing the report via a peer-to-peer file sharing site. Cyber-hacking would mean, of course, that the security of the Committee's electronic files had been breached. The Committee statement about the leak is here.
This is nothing new. There have been government leaks before. What is new is that the speed and ease of the dissemination of the leaked material was facilitated by use of the Internet in ways that Congress could not foresee. If the fired staffer had used a large enough email list he would have had the same effect. We can look for hearings and possible legislation on this issue. The answer is not to put additional restrictions on file sharing or to beef up their network. The answer is for Congress to vet its employees more carefully.