Botnet
zombie network · bot · zombie computer · robot network · réseau de machines zombies
A network of infected computers, servers or connected devices that an attacker controls remotely and makes act together without their owners knowing.
In practice
Each infected device, or bot, waits for orders from a command-and-control server. Botnets are used to launch DDoS attacks, send spam and phishing at scale, try stolen passwords or act as relays that hide other attacks. Connected devices such as cameras, routers and set-top boxes are ideal recruits: always on, rarely updated and often left with their factory password.
In 2016, the Mirai botnet infected home routers, IP cameras and video recorders by trying a short list of 62 default credentials. In late September it hit the French hosting company OVH with an attack of at least 1.1 terabits per second, a record at the time according to CISA.
How to protect yourself
- Change the default password on every connected device as soon as it is installed.
- Update routers, cameras and NAS devices, and replace those that no longer receive patches.
- Never expose administration interfaces to the internet.
- Monitor unusual outbound traffic, a sign that a machine is taking orders from outside.
