Per Motherboard:
Simo Rounela, CEO of Valtia, a Finnish company that manages the buildings, told Motherboard that the attack hit a DNS service; that is, servers that translate human-readable internet domain names into computer IP addresses.
Shortly after, Valtia received a number of alerts from one of their building’s automation systems, made by a company called Fidelix.
“Remote connection was not working, so went on-site for more inspections,” Rounela explained. The automated system controlling the heating, ventilation and hot water for the homes kept rebooting every 5 minutes. Eventually, it just didn’t boot-up anymore, he said.
We generally don’t understand the full impacts of connecting things to the Internet; it’s a hugely complex system that we can’t easily ‘fault test’ without breaking a lot of different services and systems. The result is that an attack on one aspect of the Internet – such as the DNS infrastructure – can have unexpected impacts around the world. It’s this potential for untold, and cross-national, impacts linked to cyber attacks that makes many of them so risky and dangerous to the general public.