Danfoss Controllers Hit as Cyberattack Spoils Food Across Hundreds of French Supermarkets

A cyberattack disrupted refrigeration across hundreds of French supermarkets on October 12, raising temperatures and forcing affected stores to discard fresh and frozen food. Intermarché, Cooperative U and E. Leclerc confirmed refrigeration-related disruptions, while the Paris prosecutor’s office opened an investigation into what it called a large-scale cyberattack.

The confirmed scale already extends across several major chains. Retailers said at least 300 Intermarché or Netto stores, more than 100 Cooperative U outlets and several E. Leclerc locations were targeted. Carrefour separately said 80 supermarkets were attacked, although most of its approximately 6,000 stores were unaffected. Danfoss has not disclosed how many of its control systems were involved, so retailer totals should not be treated as a count of compromised controllers.

What investigators know and what remains uncertain

BFM TV reported that the attackers remotely activated forced defrosting and altered refrigeration temperatures. Forced defrost is a normal operational function used to clear ice from refrigeration equipment, but an unauthorized command that keeps temperatures elevated can break the controlled conditions needed to preserve food. Intermarché said affected branches would have to “throw away all of the products” that were fresh or frozen.

E. Leclerc said a cyberattack affected one of its refrigeration-equipment suppliers, disrupting systems in several stores. A person close to the issue identified refrigeration controllers made by Danish manufacturer Danfoss as the target. Danfoss subsequently said its AK-SM800 and AK-SC355 controller families were notably affected. It described most affected equipment as “legacy” products that “no longer receive software or security updates” and said one version of the AK-SM800 was using outdated firmware.

A source close to the French prime minister said the national cybersecurity agency had identified a vulnerability in software supplied by a Danish company and contacted the vendor. French authorities were also coordinating with European counterparts because systems in other countries might be affected. However, no perpetrator has been identified, and neither the precise vulnerability nor the method used to gain control has been established publicly.

The prosecutor’s investigation will seek to identify victims and determine whether the cyberattack was connected to reported food losses and fires. That wording is important: fires have been reported, but their cause and relationship to individual refrigeration systems have not yet been established by the investigation.

Remote management creates a shared operating dependency

Connected refrigeration controls give retailers and maintenance providers a practical advantage. A control panel can coordinate numerous display cases, refrigerators and freezers, while remote access allows specialists to monitor temperatures and adjust equipment without traveling to every store. Across a large retail network, that can reduce response time and simplify maintenance.

The same architecture can also concentrate operational risk. If many stores use remotely reachable controllers with similar software and configurations, one software compromise can affect physical equipment at multiple locations over a short period. The result is not merely a disabled office computer: it is a temperature excursion that can invalidate inventory and interrupt the cold chain.

Unsupported equipment makes that tradeoff more severe. Once a controller no longer receives security updates, newly discovered weaknesses may remain in service even though the hardware continues performing its refrigeration-management role. Replacing such equipment can involve more than changing a box; retailers may have to coordinate software, sensors, store operations, refrigeration contractors and planned downtime. That integration burden helps explain why industrial controls often remain installed for long periods, but it does not remove the accumulating security exposure.

The incident also demonstrates why food safety and cybersecurity cannot be managed as separate functions. Temperature records, alarms, remote commands, network access and product-disposal rules form one operational system. When control integrity becomes uncertain, retailers may have to remove food from sale even before the full technical cause is known, because product condition not simply whether a refrigerator restarts determines whether normal operations can resume.

Danfoss said it had long advised customers to keep supported systems updated and migrate from legacy products to current-generation equipment. French authorities are now trying to identify other exposed companies while coordinating beyond France. The next decisive facts will be the number and location of vulnerable systems, whether affected operators can isolate or replace unsupported controllers, and whether investigators can establish a verified connection between the intrusion, the food losses and the reported fires.

By Thomas Caldwell — AMI’s senior editor for mechanical and mobility engineering, covering vehicle electronics, systems integration, electrification, chassis systems, propulsion, and safety policy.