How do you protect yourself if no click is needed?

By removing what the worm needs: an unpatched flaw or an access left open. Updates and changed default passwords are the main protection here, and caution around messages, however useful elsewhere, has no purchase at all.

Are my connected devices affected?

They're often the most exposed, because they stay on all the time, rarely update themselves, and keep their factory password. A camera or recorder forgotten in a corner is an entry point nobody keeps an eye on.

Computer Worm

In plain terms

A program that spreads by itself from one device to another, without anyone opening or clicking anything. That's what makes it fast.

Definition

A worm is malicious software that reproduces and moves through a network on its own, without needing any user action or host file. This autonomy sets it apart from a virus, which needs to be opened, and from a trojan horse, which needs to be installed.

How it works

The worm searches, from a machine where it's running, for other reachable machines, and exploits a weakness that requires no human approval to install itself there: an unpatched software flaw, an open service, a default password never changed. It then starts over from each new machine, which produces rapid progression. Two practical consequences follow. First, individual vigilance — not clicking, not opening — is powerless here: there's nothing to click. Second, protection is essentially collective and material: applying updates, changing default passwords, and not needlessly exposing a device to the internet. In a household, the router and connected devices are just as concerned as computers.

Warning signs

Network slow or saturated with no usage that explains it
Several devices on the same network behaving abnormally at the same time
Devices restarting on their own, or services stopping for no reason
Continuous outgoing traffic from a device nobody is using
A warning from your internet provider flagging unusual activity on your line

How to verify

Look at the scale: a worm affects several devices on the same network, which sets it apart from an isolated problem. Review the list of devices connected to your router and the state of their updates, especially those without a screen that get forgotten.

What to do

Enable automatic updates on everything connected, including the router and screenless devices. Change default passwords. Don't expose a device directly to the internet without necessity — which is often, without saying so clearly, what the remote-access option on many home devices does.

If it already happened

Isolate the network: cut internet access rather than turning off a single device, since the spread is lateral. Update then restart devices one by one, starting with the router. On a work network, notify IT before doing anything, since uncoordinated action can erase evidence that's needed. Report the incident to cybermalveillance.gouv.fr.

Frequently asked questions

How do you protect yourself if no click is needed?: By removing what the worm needs: an unpatched flaw or an access left open. Updates and changed default passwords are the main protection here, and caution around messages, however useful elsewhere, has no purchase at all.
Are my connected devices affected?: They're often the most exposed, because they stay on all the time, rarely update themselves, and keep their factory password. A camera or recorder forgotten in a corner is an entry point nobody keeps an eye on.

Official sources

Cybermalveillance.gouv.fr — Assistance and reporting (French government cybersecurity assistance service)

Also known as: worm, network worm.

This article is part of the Malware family. Last updated: 2026-09-03.