For a period between the end of October and November 3 2016 the heating and hot water systems in two buildings in the city of Lappeenranta, Finland were knocked out by a distributed denial of service attack designed to make the systems fail. The systems responded by repeatedly rebooting the main control circuit, which meant that the heating was never working - at a time when temperatures had already dropped below freezing. Specialists in building maintenance noted that companies often skimp on…