Botnet

A botnet is a group of compromised computers, servers or IoT devices running malware that lets an attacker control them remotely as a coordinated network. Each infected device is called a bot.

Why it matters

Botnets supply the muscle for DDoS attacks, spam campaigns, credential stuffing and click fraud. Owners rarely know their device is part of one. Because traffic comes from thousands of ordinary home or office addresses, simple IP blocking is ineffective and defenders rely on rate limiting, bot detection and DDoS mitigation.

Example

A set of unpatched home routers using default passwords is infected. On command, thousands of them send requests to one website at once, producing a traffic flood that takes it offline.

Common mistakes

• Leaving default passwords on routers, cameras and other IoT devices.
• Not updating firmware on devices that face the internet.
• Assuming a small site is too unimportant to be abused as a bot.

Related

• DDoS
• Rate limiting
• Credential stuffing
• Malware
• Tool: Uptime monitor

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