France accuses Iran's Revolutionary Guard of hacking supermarket fridges, spoiling tons of food

On the night of 11 October, the software that controls refrigeration in many of France's supermarkets was taken over by hackers. By morning, in some stores, temperatures in fridges and freezers had reportedly climbed as high as 50C (120F). Tons of chilled and frozen food had to be destroyed.

The scale of it is now clearer. More than 100 Coopérative U supermarkets were hit, along with 180 stores from Intermarché and its Netto brand. Carrefour, Monoprix and E.Leclerc were also affected. The attackers targeted software from the Danish engineering firm Danfoss, which lets retailers manage their cold units remotely.

This week the French government named who it believes is responsible: Iran's Islamic Revolutionary Guard Corps. Foreign Minister Jean-Noël Barrot called the attack unprecedented in both its scale and its level of aggression. He said it was the first large-scale cyber-attack aimed at sabotage on French national territory, and described it as a major attack on the nation's interests and the security of the French people. Paris has summoned the Iranian ambassador to lodge what Barrot called a very strong protest against an extremely grave act, and he promised that those responsible would face sanctions. France, he added, will take any other necessary and proportionate measures to deter anyone who might try to repeat it.

The judicial side is moving too. Paris prosecutor Laure Beccuau said an investigation has been opened into the head of an offensive cyber unit associated with the IRGC, and into his two deputies. She named the unit as Shahid Kaveh, which she said is affiliated with the IRGC's electronic and cyber centre. The name refers to a cluster of hackers thought to be directly employed by the Iranian regime.

Iran has not responded officially. Some Iranian media outlets have dismissed the allegations as baseless.

The French incident was not the last. Earlier this month a second wave of hacks hit more than 100 stores across Europe. Supermarkets in Belgium and Luxembourg were affected, and a smaller number of shops in Sweden, Ireland, the Netherlands, Estonia and Finland. It is not known whether the two waves are linked. Separately, in August a small number of US military bases saw fridges mysteriously malfunction and food spoil; Reuters, citing sources familiar with the matter, reports that this too is being investigated as deliberate cyber-attack.

The context is a tense one. In recent weeks, commentators and politicians in Iran have argued that any retaliation should extend beyond the Middle East if the US and Israel resume the war they began earlier this year. If the IRGC did carry out the attacks, it is unclear whether they were part of an Iranian deterrence strategy.

The attribution itself rests on thin public ground. The French government has not said how it concluded Iran was responsible, and pinning down the source of cyber-attacks is extremely difficult because hackers can hide their locations. Two Russian-aligned hacktivist groups claimed responsibility on Wednesday, though few believe them. What to watch now: the sanctions Barrot has promised, whether any evidence is made public, and whether investigators connect the French attack to the European wave and the US base incidents.