They didn't need to "hack." The were given access to the private networks, and had accounts with levels of access that they should never have been granted. I'd love to see if they went thought security clearances, which they SHOULD have been put through, if they had private access to congressional servers.
It's really appalling to me, as an IT security specialist. As a former email administrator for a company that was governed by SOX regulations, had I done what Hillary's employees did at her behest, I would be financially ruined, due to federal fines, and the CEO, the CIO, and I would be in federal prison for a very long time. Part of what SOX included was criminal penalties for both the administrators AND those who had to "sign off" on the audits.
Mark
Trump's got over six years to uncover all the criminal activity that went down under Obama... hopefully he'll get to the bottom of this scam within the next 2 years...