Supermarket chains in France hit by cyberattack

Police in France are searching for computer hackers who caused millions of euros of damage to supermarkets' inventories of frozen food by manipulating freezer controls.

The cyberattacks hit hundreds of stores belonging to chains, including Carrefour, Cooperative U, Intermarche, E. Leclerc, and Monoprix.

Investigators believe the hackers gained control of software provided by Danish engineering company Danfoss that was in use at the affected supermarket chains, using weaknesses they found to turn thermostats up to as high as 50 C.

Dominique Schelcher, chief executive of Cooperative U, said in a post on X social media platform that the cyberattacks were "extremely serious and unprecedented" and had overridden the freezer controls at more than 100 of the chain's supermarkets.

Intermarche and its Netto brand said freezers in around 180 of its stores had been tampered with. It said it had urgently disconnected freezers from the internet in around 100 other stores, to prevent them from suffering the same fate.

Danfoss said the older models of freezers had been susceptible to the cyberattack because they did not have up-to-date security software. The company said it had identified the risk before the attack and issued warnings.

"Reliable refrigeration is critical to our customers' operations, and we remain committed to supporting our customers and helping them maintain the secure and reliable systems they are used to," it said.

French media outlets said around 490 supermarkets out of the nation's around 15,000 had been impacted by the cyberattack.

Mousquetaires Group, which owns Intermarche and Netto, told the BBC its stores had "taken all necessary precautions" to remove compromised products from freezers, and that workers were restocking as quickly as possible.

Reuters said the attack happened on Sunday night and Monday morning and lasted for around six hours. It said food that may not have been damaged was also discarded as a precaution.

French broadcaster BFMTV said one freezer full of ice cream had risen in temperature to 26.5 C by Monday morning.

The Paris prosecutor's office said it was investigating the "large-scale cyberattack affecting the refrigerators of several major food retail chains across France".

France's Prime Minister Sebastien Lecornu said he had also ordered the National Cybersecurity Agency to investigate the attacks.

He said French law enforcement agencies would also work with counterparts across Europe, to ensure similar attacks are not repeated elsewhere.