WASHINGTON — The Pentagon is treating the spate of mysterious freezer malfunctions that spoiled food at military bases across the United States in August as a suspected hack, according to four officials familiar with the matter who spoke to Reuters.

Source: Reuters via WNCY

The late-August malfunctions affected at least six commissaries — the on-base stores where military personnel buy their food — according to a Reuters review of the bases' contemporaneous Facebook posts and website updates. In at least one case the freezers did not simply stop working: the cooling units' temperatures were cranked up overnight, leaving mounds of wilted or melted food in the morning. The Fort Huachuca, Arizona, base account explained on August 26 that its freezer "went into defrost mode where it heated up all the food. Trust us when we say it was 'spoiled.'"

Source: Reuters via WNCY

Asked about the investigation, the Pentagon said a unit of Cyber Command — the military's cyber force — was "working in close coordination with interagency and law enforcement partners," Reuters reported. The US Army Criminal Investigation Division said its Cyber Field Office was involved and was working with French law enforcement to better understand "the refrigeration outages in Europe." One official said military investigators were in touch with their French counterparts about the similar cyberattack on commercial freezers in France earlier this month.

The French case is the earlier development this investigation builds on: hackers overrode the temperature controls on commercial cooling units in more than 350 establishments across France, clearing frozen-food aisles of spoiled merchandise, and some units were turned up so high they caught fire, Reuters reported. One supermarket owner estimated earlier this month that the French attack's total costs could add up to tens of millions of euros nationwide — yaani, losses running into several crore euros. Experts previously told Reuters the French attack appeared easy to pull off, and the Danish firm Danfoss, whose controllers ran many of the stricken French units, said many were obsolete or running outdated firmware; Reuters could not establish whether Danfoss or any other brand of controller was in use at the affected US bases, and Danfoss did not return messages seeking comment.

Reuters said it was not able to ascertain how far along the Pentagon's investigation was, or whether it had reached any conclusions about what happened or who might be responsible — no attacker has been named. The spate of rogue freezer behaviour and the possibility of cybersabotage were first reported on August 28 by a blog called Signal and Silence; the involvement of military investigators was reported by the newspaper Stars and Stripes, and their contacts with the French by Britain's Daily Telegraph, Reuters said.