Actually, it's an extension of the DNC hack. An auxiliary system maintained by the DNC containing a data base that both Sanders and Clinton campaigns could access was breached. The Clinton campaign maintains that their internal servers have been thoroughly inspected and have not been affected.
Off the top of my head I can ramble off a number of corporations that have had their servers breached, including Bank of America, Blue Cross, Target, Sony, Anthem Heath, etc.
I find it sad that there is a blame the victim mentality about these hacks, despite the fact that the FBI quite clearly believes that these DNC attacks, along with attacks on the Pentagon, DOJ and other government agencies, are initiated by Russia. All Americans, regardless of political affiliation, should be outraged that a foreign government appears to be interfering in an American presidential election. Regardless of who ends up being president next year, we will all still be Americans, after all.
I just don't understand the mindset of many on this forum.