Halvor Molland was asleep on a brisk night in Oslo, Norway’s capital, two years ago when his phone rang around 3 a.m.
The computer servers of Norsk Hydro, the global aluminum producer where Molland is senior vice president for communications, had seized up as a crippling ransomware infection spread through the company’s networks.
“The feeling is: You really don’t believe it,” Molland recalled in a recent interview. “There was a decision then to shut down the network altogether, because at some point there was nothing left to isolate.”