A disastrous day for French supermarkets after massive cyberattack targets refrigeration systems

Charles Dezon, owner of the Intermarché supermarket in Gradignan, in southwestern France, had never imagined that one day he would have to throw away nearly an entire dumpster’s worth of frozen food because of a cyberattack. His store, along with around 300 others in the same group – which also includes the Netto brand, as well as 100 Coopérative U stores, 80 Carrefour stores, several members of the E.Leclerc network and around 30 Monoprix stores –, was hit by a large-scale cyberattack targeting refrigeration systems overnight from October 11 to October 12, according to BFM-TV , which first reported the attack.

"The attack was probably launched around 11 pm, but we only realized it at 4 in the morning when our delivery driver saw the storeroom was flooded. The temperature had reached 50°C [122°F] in the cold room, which set off a sprinkler," Dezon told Le Monde .

In addition to raising the temperature of the defrosting system in freezers and cold-storage rooms to 50°C, the hackers extended the defrost cycle from one hour to eight hours so that alarms would go off later. The method delayed intervention and increased the damage. According to a post by the Intermarché in La Haye, in Normandy, some of the store’s equipment melted as temperatures climbed to 80°C [176°F].