Fridges in French supermarkets hit by cyber attack

The hackers did not simply switch off individual fridges. They gained control of software that regulates refrigeration temperatures and ordered cold units to warm up and stay hot. This mattered because supermarkets depend on steady temperatures to protect fresh and frozen food.

Intermarché said some fridges heated to 50C for six hours overnight into Monday. A freezer in an ice-cream aisle showed 26.5C, and managers in several branches encountered hot air from the units. Some locations even reported small fires.

The attack affected software supplied by Danish engineering firm Danfoss. The company said the targeted units were older models with security software that could not be updated against an identified risk. Stores disconnected some systems, removed affected products, and threw away food when its safety or condition could not be guaranteed.

The attack reached several major French food retailers rather than one isolated chain. More than 100 Coopérative U supermarkets were targeted, while 180 Intermarché and Netto stores were affected. Carrefour reported 80 hacked stores, and Monoprix said 5% of its more than 400 stores were hit.

Individual figures suggest about 400 stores were affected out of roughly 15,000 supermarkets across France. Intermarché also disconnected another 100 shops from the internet urgently, to prevent the same attack from reaching them. Carrefour, Monoprix and E.Leclerc were among the other retailers reporting effects.

The financial damage remains uncertain. Two supermarkets in Alsace reported combined losses of €270,000. Because food was discarded across many chains, the national cost could run into millions of euros, although the full scale had not been established.

Refrigeration protects food by keeping it cold, while freezing preserves frozen products. When units heat dramatically, food can spoil or lose the condition needed for safe sale. The article reports that stores removed products whenever their condition could not be guaranteed.

Intermarché said its fridges reached 50C for six hours overnight and that it threw away all affected food to avoid health risks. Monoprix also removed food from sale where safety or condition was uncertain. A freezer in one ice-cream aisle displayed 26.5C, showing how far conditions could move from normal cold storage.

The response caused major waste and financial losses, but it reduced the chance of selling compromised food. The article does not provide a precise safe-temperature threshold or identify specific illnesses. It does show that retailers treated the temperature exposure as serious enough to empty units and restock them later.

Remote refrigeration-management software is a digital system that allows retailers to manage cold units from a distance. The article says Danfoss supplied the software and that it lets businesses manage refrigeration units remotely. This makes it possible to coordinate equipment across stores without visiting every freezer.

The attackers exploited that remote control. They gained control of the temperature-regulating software and ordered some units to heat up and remain hot. The same software was used by several major retailers, including Coopérative U, Intermarché, Netto, Carrefour, Monoprix and E.Leclerc, allowing the incident to spread across many sites.

The article does not describe the software’s exact network design or how attackers entered it. It does show the operational risk of connected refrigeration: a problem in shared control software can disrupt equipment far from the original system. Retailers disconnected some stores from the internet to block further effects.

Older refrigeration units were more exposed because Danfoss said their security software could not be updated to address a risk the company had identified. Danfoss said it had long advised businesses to keep supported systems up to date. Unmaintained software can therefore leave known weaknesses in place.

An update could strengthen the security of systems that still support one. That may reduce the chance of unauthorised control, although the article does not claim that updating would guarantee protection. For units that cannot be updated, limiting their connection may be important.

Intermarché provides a direct example: after 180 stores were affected, another 100 shops were urgently disconnected from the internet. This did not repair the affected equipment, but it was intended to prevent the same thing happening there. The incident shows why retailers need replacement plans for unsupported units and rapid isolation procedures.

Danfoss is the Danish engineering firm whose software controlled the affected cold units. It said older models could not receive security updates against an identified risk and stressed the importance of keeping supported systems current. The company also said it would support customers in maintaining secure and reliable systems.

The supermarket chains were responsible for responding in their stores. Coopérative U, Intermarché, Netto, Carrefour, Monoprix and E.Leclerc reported impacts. Staff disconnected some shops, removed food, discarded products exposed to dangerous warming, and worked with refrigeration specialists to restore operations and restock shelves.

French prosecutors are investigating the incident as a specific cyber-crime case. The Paris prosecutor’s office called it a large-scale cyber-attack affecting refrigerators across France. European Food Commissioner Christophe Hansen condemned the hack, while Coopérative U chief executive Dominique Schelcher called for an investigation.

The food cold chain is the continuous use of refrigeration or freezing to keep food in the required condition as it moves through storage and retail. Supermarket fridges and freezers are a crucial final part of that system. If cooling fails, fresh and frozen products may no longer be suitable for sale.

In this incident, hackers controlled temperature software supplied by Danfoss. Some units heated to 50C for six hours, while one ice-cream freezer displayed 26.5C. Stores removed products when their condition could not be guaranteed, and Intermarché discarded all affected food to avoid health risks.

Reliable refrigeration protects both food supplies and retailers’ businesses. The attack affected about 400 stores, caused reported losses of €270,000 in two Alsace supermarkets, and could cost millions nationally. The response highlights the need for secure systems, supported equipment, and plans to isolate affected stores quickly.