The phrase "massive hack" refers to a significant or large-scale unauthorized access into computer systems or networks. It implies that a considerable amount of data or information has been compromised or stolen by hackers. Full definition
Yahoo finally acknowledges massive hack of user data, only informed Verizon two days ago (Talking New Media) Verizon is buying Yahoo. (ebookevangelist.com)
In the past, we have experienced massive hacks on cryptocurrency exchanges, with the most recent being (smartbitcoininvestments.com)
While Congress has struggled to pass any comprehensive cyber legislation impacting the private sector as a whole, the growing number of massive hacks against companies like Anthem and Sony will likely spur them to continue regulation efforts. (cnbc.com)