Mysterious cyberattacks are hitting grocery store refrigeration systems across Europe and the U.S., and officials don't yet know who is responsible.

• Fridges and freezers at supermarkets in Belgium, Sweden, Ireland, Estonia, and Luxembourg overheated in a suspected cyberattack, ruining huge amounts of food.
• A similar attack hit over 500 stores in France weeks earlier, with some fridges overheating badly enough to catch fire.
• Six grocery stores on U.S. military bases had the same kind of failure, suggesting the problem isn't limited to Europe.
• The pattern looks like someone testing whether they can take down an entire country's food supply through hacking.
• The U.S. just launched a plan called Fortress to help military bases keep running if power grids and other critical systems get knocked out, partly in response to this; separately, Iran has warned it has a "surprise weapon" that could target undersea internet cables, data centers, and AI facilities if fighting resumes.

Outlook: Expect more scrutiny of food and infrastructure cybersecurity as governments try to identify who's behind the attacks before they spread further.