India, Oct. 14 -- A cyberattack knocked out fridges and freezers at about 700 of France's 10,000 supermarkets, French finance minister Roland Lescure told Parliament on Tuesday. Some stores had to bin food. Danfoss, the Danish company that supplied the refrigeration management software, said most of the affected systems were older products that no longer received software or security updates.

Machines that are left running on code no longer monitored or patched are one reason security specialists treat almost every connected device as hackable. Anything with a chip and a network connection runs code, all code has bugs, and an attacker with enough time and money will find one.

The attack hit refrigeration management systems, the computer...