Supermarkets in Sweden, Belgium, Ireland, Luxembourg, the Netherlands, and Estonia reported problems with their fridges and freezers. The problems started overnight before Monday, November 2. Stores suspect that people used computers to change the settings from far away. Some Swedish freezers reached 122 degrees Fahrenheit.
Stores threw away food after it became too warm. In Belgium, 15 Carrefour stores reported problems. In Ireland, 13 SuperValu stores had problems. Belgium's federal prosecutor's office opened an investigation, but investigators do not know who caused the attacks.
A Belgian company that manages supermarket cooling equipment said attackers turned on a setting that melts ice inside the equipment. Stores connect these systems to the internet so workers can check problems from far away. Workers can also change settings without visiting the store. Computer safety experts recommend keeping these controls off the open internet and using safer connections.
In a separate series of attacks, hundreds of French supermarkets had similar problems in October. Some stores in France and other affected countries used cooling technology from the same company, Danfoss. However, investigators have not shown that the same people or the same computer weaknesses caused both groups of attacks.
