A botnet is a group of internet-connected devices that have been infected and quietly controlled together. The owner may still use the device normally while it is also taking instructions from someone else.
Does this affect you?
Use this for computers, phones, routers, security cameras, smart speakers, and other smart home devices. Any internet-connected device can become part of a botnet if compromised.
How a botnet works, step by step
The infection path is familiar, but the scale is what makes botnets powerful.
- A device gets infected through a phishing link, malicious app, unpatched vulnerability, weak router setting, or default smart-device password.
- The malware connects quietly to a command server run by the botnet operator.
- The device becomes one bot among many, sometimes thousands or millions of devices spread across homes and businesses.
- The operator sends commands to the whole network at once.
- The owner often notices little or nothing because good botnet malware tries not to slow the device enough to attract attention.
What botnets are used for
One infected device is small. Many infected devices acting together can do damage.
- DDoS attacks flood a website or service with traffic until it becomes unavailable.
- Spam and phishing campaigns can be sent from many infected devices to avoid easy blocking.
- Credential stuffing uses stolen username-password pairs against many sites at high speed.
- Cryptocurrency mining can steal processing power and electricity from infected devices.
More control
Smart devices are attractive targets
Routers, cameras, and smart gadgets often run all day, get few updates, and may keep factory passwords. Change default passwords as soon as devices are installed.
Keep firmware updated
Install router, camera, computer, phone, and smart-device updates. Many botnet infections rely on known vulnerabilities that updates already fix.
Watch for quiet symptoms
Unusual data use, slowdowns, hot routers, random restarts, or device lights active when idle are worth checking. Restart the device, update firmware, and change passwords if something looks wrong.
Sources
- CISA – Botnets (2025)
- FBI Internet Crime Complaint Center – Botnets (2025)
- Cloudflare Learning Center – What Is a Botnet? (2025)