Botnet: What it is, how it works, and how to spot and remove it

Botnet

What it is

A botnet is a remote-controlled crowd of infected devices - PCs, phones, routers, even cameras - all taking orders from a command server. Criminals use these “bots” for spam blasts, DDoS attacks, credential stuffing, malware drops, click fraud, or cryptomining - and they often rent them out as a service. 

What you may notice

  • Internet feels slow; router lights blink nonstop

  • CPU/GPU runs hot when you’re idle (fans roar, battery drains)

  • Abuse notices from your ISP / email bounces you didn’t send

  • Unknown processes, new services, or odd outbound connections

How it spreads

  • Phishing attachments and fake installers

  • Weak or reused passwords on RDP/SSH/IoT devices

  • Unpatched routers, cameras, NAS, or VPNs

  • Drive-by downloads and malicious extensions

If you suspect you’re part of a botnet

  1. Disconnect from the network (PC and smart devices).

  2. Scan and clean with trusted anti-malware; reboot.

  3. From a clean device, change passwords and enable MFA.

  4. Update router/IoT firmware; disable UPnP, remove risky port forwards, check DNS.

  5. Factory-reset compromised IoT gear; rejoin the network gradually and monitor traffic.

Prevent it

  • Keep OS, apps, routers, and IoT patched.

  • Use unique, strong passwords + MFA; never expose admin panels to the internet.

  • Install software and extensions only from official sources.

  • Run reputable EDR/AV and consider DNS filtering for known bad domains.

    Glossary (A–Z)

    All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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