What Is a Botnet? Explained Simply

What a botnet is

A botnet is a network of internet-connected devices that have been infected with malware and are secretly controlled by an attacker, often without the device owners knowing. The name combines 'robot' and 'network.' Each infected device, called a 'bot' or 'zombie,' quietly follows the attacker's commands. By controlling thousands or even millions of devices at once, an attacker commands a powerful, distributed force that can be used for large-scale malicious activity. Botnets are a major tool in cybercrime.

How devices get recruited

Devices are recruited into a botnet by being infected with malware, often without the owner noticing. This can happen through Trojans, worms, malicious downloads, or by exploiting unpatched vulnerabilities. Once infected, the device secretly connects to the attacker's control system and awaits commands, continuing to function normally so the owner has no idea. Any internet-connected device can be targeted, including computers, servers, and increasingly the many smart home and Internet of Things devices with weak security.

Controlled remotely

What makes a botnet powerful is central control. The attacker, often called the 'bot herder,' can send commands to all the infected devices at once through a command-and-control system. This lets them coordinate the entire network for a single purpose, marshaling the combined power of all those hijacked devices. Because the force is distributed across many devices in many locations, it is also hard to shut down, and the scale can be enormous.

What botnets are used for

Botnets are used for a range of malicious activities that benefit from many devices acting together. A major use is launching DDoS attacks, overwhelming a target with traffic from thousands of devices at once. Botnets also send massive volumes of spam email, perform large-scale fraud, mine cryptocurrency using victims' resources, and spread more malware. The combined computing power and internet connections of a large botnet make these large-scale attacks possible.

How to protect your devices

Protecting your devices from becoming part of a botnet relies on good security hygiene. Keep your operating system, software, and devices updated so known vulnerabilities are patched. Use reputable security software. Be cautious about downloads, links, and attachments that could carry malware. Importantly, secure your smart home and Internet of Things devices by changing default passwords and keeping them updated, since these are increasingly targeted. Vigilance keeps your devices from being quietly conscripted.

Why it matters

Botnets are behind many of the largest and most disruptive cyberattacks, from massive DDoS assaults to huge spam and fraud campaigns. Understanding them clarifies how attackers harness armies of hijacked devices, why your own devices could be unknowingly involved, and why securing every internet-connected device matters. For anyone interested in cybersecurity, the botnet is an essential concept that shows the scale and coordination of modern threats.

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See also: What is a DDoS attack? Explained, What is the internet of things (IoT)? Explained.

Sources

• Botnet - Wikipedia

Published date reflects the original event date (2023-08-29). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.