A cyberattack on supermarket refrigeration systems across France has forced retailers to discard large quantities of fresh and frozen food after hackers remotely interfered with temperature controls, turning essential cold-storage facilities into dangerously hot spaces.
The attack, which occurred overnight on October 11–12, affected stores operated by major retail groups, including Carrefour, Intermarché, Netto, Coopérative U, E.Leclerc and Monoprix. Temperatures in some refrigeration rooms reportedly climbed to 50°C, while some installations suffered more severe equipment damage.
According to Reuters and Le Monde, the incident prompted a criminal investigation after food losses and fires were reported at several locations. French Prime Minister Sébastien Lecornu directed the country’s National Cybersecurity Agency (ANSSI) to investigate the attack.
How hackers turned refrigeration systems against retailers
The attackers reportedly gained remote access to connected refrigeration-control systems and manipulated their defrost settings. Instead of maintaining the low temperatures required to preserve food, the systems were made to run extended defrost cycles.
In one case reported by Le Monde, a supermarket owner said the temperature in a cold room had reached 50°C by the time the disruption was discovered early in the morning. The overheating reportedly triggered a sprinkler system, while other affected stores experienced equipment damage.
The incident demonstrated how cybercriminals can disrupt physical operations without necessarily targeting payment systems, customer databases or conventional IT networks. By interfering with equipment responsible for preserving food, attackers can create substantial financial losses and potentially compromise food safety.
Danfoss systems under scrutiny
Investigators identified refrigeration-management software supplied by Danish engineering company Danfoss as a potential point of vulnerability in the initial wave of attacks. The company said many affected installations were obsolete and no longer receiving software or security updates.
Danfoss had previously issued security advisories concerning vulnerabilities in some of its systems and urged customers to install available updates or migrate from unsupported equipment to newer solutions.
However, the precise method used in the attack, the identity of those responsible and the extent to which previously disclosed vulnerabilities were exploited remained under investigation.
Hundreds of stores affected
The scale of the disruption was significant. According to reporting by Le Monde, around 300 Intermarché and Netto stores, approximately 100 Coopérative U outlets, 80 Carrefour stores and about 30 Monoprix locations were among those affected. Several E.Leclerc stores also reported problems.
Retailers faced the immediate task of removing potentially compromised stock, assessing equipment damage and restoring refrigeration operations. Losses were expected to run into millions of euros, with some reports suggesting that the overall impact could reach tens of millions.
The incident also highlighted the operational risks associated with connected equipment used across large retail networks. Refrigeration systems are essential infrastructure for supermarkets, particularly those handling meat, seafood, dairy products, frozen foods and other temperature-sensitive goods.
A warning for the food industry
The attack raises important questions about cybersecurity across the food supply chain. Supermarkets increasingly depend on remotely monitored equipment to manage refrigeration, energy consumption, inventory and store operations. While connectivity can improve efficiency, outdated software, weak access controls and internet-exposed devices can create opportunities for malicious interference.
For food retailers and manufacturers, the implications extend beyond financial losses. A refrigeration failure can force the disposal of entire batches of products, disrupt deliveries, increase food waste and create uncertainty over whether affected goods remain safe for sale.
Cybersecurity experts and equipment manufacturers have repeatedly stressed the importance of installing security updates, replacing unsupported systems, restricting remote access and separating operational technology from ordinary corporate networks.
The French incident is a reminder that food safety depends not only on hygiene standards, inspections and temperature monitoring, but also on protecting the digital systems that keep food safe. As the investigation continues, the case could prompt retailers across Europe and elsewhere to reassess the security of their refrigeration and other critical store infrastructure.