A German power utility specialising in renewable energy was hit by a serious cyber-attack two weeks ago that lasted five days, knocking its internet communications systems offline, in the first confirmed digital assault against a European grid operator. “It was a DOS (‘Denial Of Service’) attack with a botnet behind it,” Boris Schucht, the CEO of 50Hertz told EurActiv on the fringes of a Brussels renewables conference. “It blocked our internet domains so that in the first hours, all email and connectivity via the internet was blocked.” DOS attacks involve thousands of requests being sent to a server each second...