Supermarkets across Europe reported problems with their fridges and freezers on Monday, 2 November. The problems started during the night. Shops in Belgium, Sweden, Ireland, Luxembourg, the Netherlands and Estonia reported trouble. People used computers to change the cooling controls from outside some shops.
Some Swedish freezers reached 50°C. Shops had to throw away food after it became too warm. In Belgium, 15 Carrefour shops had problems. In Ireland, 13 SuperValu shops reported problems too. Investigators do not yet know who caused the attacks.
Many supermarket cooling systems connect to the internet. This lets workers check problems and change settings without visiting a shop. But attackers can also change temperatures if they get into these systems. In Belgium, a company said someone changed the controls to melt ice in the cooling equipment.
In a separate attack in October, hundreds of French supermarkets had similar problems. Investigators have not shown that the same people carried out both attacks. Computer safety researchers say shops should remove cooling controls from the open internet. Workers should use safer ways to connect.
