North Korea was behind the theft of approximately $1.5bn in virtual assets from a cryptocurrency exchange, the FBI has said, in what is being described as the biggest heist in history.The haul, which reportedly has since lost some of its value, exceeded the previous record sum of $1bn stolen by the dictator Saddam Hussein from Iraq’s central bank before the 2003 war, and underlines the North’s growing expertise in cybercrime.Describing this particular form of North Korean malicious cyber activit...