India, Nov. 3 -- Hackers who drove supermarket freezers across Europe up to 50degC on Monday could have gotten in through ageing control systems left reachable online, analysts say, warning that the aim of the cyberattacks seems to be to show just how easily food supply can be hit.

Stores in at least six countries, including Sweden, Finland, Belgium, Luxembourg, Ireland and Estonia, found fridges and freezers heated overnight, forcing them to throw out mounds of food.

The attacks followed a first wave in France in mid-October that hit between about 350 and 700 stores. Separately, in the US, the Pentagon is treating freezer failures at military bases in August as a suspected hack, Reuters reported on October 29.

The controllers behind t...