When a Hacker Turns Off the Freezer: Cyberattacks on the IoT and How to Secure Your Smart Home

It sounds like the plot of a sci-fi movie, but in October and November 2026, it became a harsh reality. Hundreds of European supermarkets (including the E. Leclerc and Intermarché chains) lost hundreds of metric tons of fresh and frozen food. Attackers remotely took control of the cooling systems, switched them to defrost mode, or simply set the temperature to 50 °C.

This incident fully exposed the catastrophic state of Internet of Things (IoT) security. While the commercial sector was affected by vulnerable Danfoss controllers exposed to the public internet with weak passwords, households face an equally serious threat. Your smart refrigerator, robot vacuum, or smart light bulb could at any moment become a gateway into your network or part of a global botnet.

How Hackers Exploit Home Appliances

Smart home appliances often have extremely weak computing hardware running an outdated and unpatched version of Linux. Manufacturers focus on features but ignore security. When a hacker attacks a home refrigerator, they usually have three goals:

1. Botnets and DDoS attacks: The refrigerator is silently infected with malware (such as the infamous Mirai) and joins an army of thousands of other infected devices. At the attacker’s command, these appliances then begin generating massive amounts of network traffic and taking down the servers of banks, hospitals, or government institutions.
2. Cryptomining: Although a smart refrigerator has a weak processor, with thousands of compromised units, attackers can quietly mine cryptocurrencies in the background while your electricity bill creeps up unnoticed.
3. Local network intrusion: If the refrigerator is on the same network as your work computer or home NAS server, an attacker can use it as a “pivot.” From the compromised appliance, they can scan the network, capture passwords, or deploy ransomware against your work files.

How to Set Up Bulletproof Protection for Your Home IoT Network

The basic security rule in the era of the Internet of Things is Zero Trust toward any device labeled “smart.” To secure your home against such attacks, you must implement network isolation and strict communication rules.

1. Strict isolation via VLAN or a guest network (Guest Wi-Fi)

Never connect IoT devices (refrigerators, TVs, vacuum cleaners, smart plugs) to the same network where your primary work computer, smartphone, or data storage is connected. Most modern routers offer a Guest Wi-Fi feature. Create a separate wireless network exclusively for smart devices and enable the AP Isolation (or Client Isolation) feature for it in your router’s settings. Devices on this network will have internet access so their apps can function, but they won’t be able to see each other or your personal devices on the main network. For more advanced networks, set up a dedicated VLAN.

2. Network-Level DNS Blocking (Deploying NextDNS)

Since you can’t install antivirus software on a refrigerator, you must filter threats at the network level. The ideal solution is to deploy a service like NextDNS directly on your main home router. This step gives you control over who your appliances communicate with. NextDNS, operating at the encrypted DNS protocol level, will immediately block any attempt by your refrigerator to connect to known C&C (Command & Control) botnet servers, prevent cryptocurrency mining, and dramatically limit the aggressive telemetry that many manufacturers send to Chinese or American servers.

3. Disabling the UPnP feature on the router

The Universal Plug and Play (UPnP) feature is designed to allow devices on the network to automatically open ports to the public internet. In practice, this is a massive security vulnerability. Thanks to UPnP, an infected device can open a backdoor into your network without you even realizing it. Open your router’s admin interface, find the UPnP settings, and disable it immediately.

4. Disabling Internet Access (Dumb Mode)

If you bought a refrigerator or washing machine primarily for its physical features and don’t actually use its smart functions, there’s a very simple solution: don’t connect it to Wi-Fi. A device that doesn’t have an IP address and doesn’t communicate with the outside world cannot be hacked. If the appliance constantly requires a connection, connect it, download the latest firmware, and then permanently block its access to the WAN (internet) on your router via its MAC address.

Relying on a home appliance manufacturer to write secure network code is a risk these days. Your home network architecture must be designed so that the compromise of a single sensor or appliance in no way jeopardizes the integrity of the rest of your technology.