US government warns of ongoing cyber threat amid hacks of industrial, retail, military freezers

The U.S. government has issued a warning about an “ongoing cyber threat” to industrial refrigeration equipment, after reports of attacks on freezers and fridges in supermarkets worldwide, on U.S. military bases and on at least one French blood bank.

In a joint statement released on Thursday, the Cybersecurity and Infrastructure Security Agency (CISA), the FBI and several other federal departments said hackers are compromising internet‑connected refrigeration and cold‑chain monitoring systems used in grocery outlets and cold‑storage sites. The agencies added that the intrusions affect critical infrastructure including food, agriculture, transport and the shipment of medicines.

“If successfully exploited, the actors could change the temperature and possibly cause physical impacts such as fire hazards, loss of inventory and changes to the service life of the system,” the statement warned.

The alert follows a series of attacks on industrial refrigeration units that have hit the United Kingdom and other European nations in recent weeks. Two distinct waves allowed perpetrators to raise temperatures on freezers and chilling units in at least a dozen countries, leading to spoiled food and ruined produce. Some of the compromised equipment was made by Danish firm Danfoss, which had ceased providing security updates for its customers’ units.

Hackers also attempted to breach a blood bank in France, causing its refrigerated storage to increase temperatures in units holding donated blood, though the intrusion was halted before the blood supplies were compromised. The U.S. Department of Defence is probing a cluster of attacks on military‑run freezers, according to Reuters, with the initial reports coming from Signal and Silence.

While the United States has not formally linked the incidents to any specific group or state, security researchers have broadly pointed to Iran, and U.S. officials have reportedly said Iran is the most likely actor.

CISA, the FBI and the Departments of Agriculture, Health and Human Services and Transportation urged organisations that rely on refrigeration and monitoring to disconnect remote‑control functions from the internet, strengthen passwords, apply available patches and retire equipment that no longer receives vendor support.

A separate fact sheet from the departments warned that attackers might try to “force units into continuous heating and defrost cycles, which can cause widespread inventory loss and equipment hazards.”

“Every organization that depends on refrigeration and monitoring systems should assume it could be a target,” said Chris Butera, acting cybersecurity chief at CISA.