US government warns of ongoing cyber threat targeting industrial, retail and military freezers

US cybersecurity agency CISA, the FBI and several other federal departments issued a joint statement on Thursday warning of an “ongoing cyber threat” to industrial refrigeration units after reports of attacks on freezers and fridges in supermarkets worldwide, on US military bases and at a blood bank in France.

The agencies said hackers are compromising internet‑connected refrigeration and cold‑chain monitoring systems in grocery stores and cold‑storage facilities, targeting critical infrastructure such as food, agriculture, transportation and medicine‑shipping sectors, and could alter temperatures to cause fire hazards, inventory loss or reduced equipment life.

Recent waves of attacks across the United Kingdom and Europe allowed hackers to raise temperatures on freezers in at least a dozen countries, spoiling food and damaging produce, with some of the affected units made by Danish company Danfoss, which had stopped providing security updates for its customers’ freezers.

Hackers also attempted to boost temperatures in refrigerated units at a French blood bank, but the intrusion was halted before blood supplies were compromised; the US Department of Defence is investigating a series of hacks on military freezers, according to Reuters, and while no group has been officially named, security researchers have broadly linked the activity to Iran and US officials reportedly suspect Iranian involvement.

CISA, the FBI and the Departments of Agriculture, Health and Human Services and Transportation urged organisations to remove remote‑control capabilities from the internet, strengthen passwords, apply available patches and retire unsupported equipment, adding that hackers may 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 CISA’s acting cybersecurity chief Chris Butera.