Hackers Tamper With Estonian Supermarket Freezer

Attackers changed a freezer’s temperature setting to 50°C at an unnamed Estonian supermarket chain, Kitman Coldtech CEO Jann Mutso told ERR in a report published November 2.

He said his company responded within 10 minutes of receiving the report, preventing damage. The supplier declined to identify the retailer. The attacker’s identity remains unestablished in the published account.

A setting with physical consequences

According to Mutso, intruders reached the control computer of an older Danfoss refrigeration system. He said outdated controllers were being targeted.

The reported 50°C figure describes the manipulated setting. ERR’s account provides no verified measurement establishing that stored food reached that temperature.

The incident illustrates how access to a digital controller can affect equipment responsible for keeping food safe. The supplier’s account is the source for what happened inside the unnamed store.

Earlier warnings about industrial controls

In a December 2023 assessment, Estonia’s Information System Authority, RIA, documented attacks that disabled remote controls at heating plants and water facilities. Some operators maintained services through manual operation.

RIA recommended keeping industrial controls off the public internet, protecting necessary remote access, separating industrial networks and preparing crisis plans.

More recently, France’s CERT-FR reported multiple compromises involving Danfoss and other refrigeration controllers. Its alert was issued October 12 and updated October 16.

The French agency advised operators to remove direct internet exposure, inspect equipment configurations and restore remote access through a secure VPN or protected network. It also recommended following manufacturers’ security instructions, including firmware updates and changing default passwords.