Iran rejects French claims it was behind supermarket fridge hacking

France has accused Iran's Islamic Revolutionary Guard Corps (IRGC) of being behind cyber-attacks that raised the temperatures of supermarket fridges and freezers across the country last month.

Foreign Minister Jean-Noël Barrot said the attack was "unprecedented in both its scale and its level of aggression", adding those who were responsible would be hit with sanctions.

Iran has yet to respond officially, but some Iranian media outlets have dismissed the allegations as baseless.

The French hacking, which led to the destruction of tons of frozen and chilled food in France was followed by a similar attack against supermarkets across several other European countries. It is not known if the instances are linked.

Barrot said the attack on France's supermarkets "marks the first large-scale cyber-attack aimed at sabotage on our national territory, and it constitutes a major attack on the nation's interests and the security of the French people".

He said the government had summoned the Iranian ambassador to Paris to "lodge a very strong protest against this extremely grave act".

France will take "any other necessary and proportionate measures" to respond to the incident and "deter anyone who might seek to repeat it", Barrot added.

The Paris prosecutor said an investigation had been opened into the head of an offensive cyber unit associated with the IRGC as well as his two deputies.

Laure Beccuau named the unit as Shahid Kaveh, which she said had an affiliation with the electronic and cyber centre of the IRGC.

Shahid Kaveh is the name given to a cluster of hackers thought to be directly employed by the Iranian regime.

In recent weeks, a number of commentators and politicians in Iran have argued that the country should extend any retaliation beyond the Middle East if the US and Israel resume the war they started earlier this year.

If the IRGC carried out the cyber-attacks, it remains unclear whether they were part of Iran's deterrence strategy.

On 11 October, hackers gained control of the software that regulates the temperatures of the refrigeration units used in many of France's supermarkets.

More than 100 of Coopérative U's supermarkets were hit, as well as 180 stores from Intermarché and its Netto brand. In some stores, temperatures of the fridges reportedly rose to 50C (120F) overnight.

Other major food retailers including Carrefour, Monoprix and E.Leclerc were also hit by the attack, which targeted software provided by Danish engineering firm Danfoss.

The software allows retailers to manage their cold units remotely.

Earlier this month a second wave of hacks took place, hitting more than 100 stores across Europe.

Supermarkets in Belgium and Luxembourg were affected, while a smaller number of shops were hit in countries including Sweden, Ireland, the Netherlands, Estonia and Finland.

Separately in August a small number of US military bases had fridges mysteriously malfunction, spoiling food. This incident is also being investigated as deliberate cyber-attacks, Reuters news agency has reported, citing sources familiar with the matter.

Since the waves of attacks on freezers, experts have been speculating which hacking groups could be responsible, with Iran being on a list of potential suspects.

In spite of a pair of Russian-aligned hacktivist groups claiming they were responsible on Wednesday, few believed them.

The French government has not said how it reached the conclusion that Iran was responsible, and attribution of cyber-attacks is extremely hard as hackers are able to hide their locations.