Botnet je síť počítačů nebo zařízení s prolomeným zabezpečením, které může útočník vzdáleně ovládat a provádět s nimi škodlivé činnosti.

What is botnet?

Botnet is a network of computers, servers, or smart devices that have been infected with malware and secretly taken over by an attacker. The owner of the infected device is usually unaware that it’s being controlled. The attacker can remotely command the entire botnet to perform malicious activities—such as launching large-scale DDoS attacks, sending spam, spreading malware, or attempting brute-force logins on other systems.

How botnet appears in practice

Examples of real-world scenarios:

• A company laptop infected with malware joins a botnet as soon as it connects to the internet—without the user's knowledge.
• An attacker uses thousands of compromised devices to overwhelm an e-commerce website, bringing it offline (DDoS attack).
• Unsecured printers or IP cameras in a company network are quietly hijacked and used as nodes in a botnet.
• The corporate email server unknowingly starts sending thousands of spam emails.
• The botnet attempts to brute-force access to a company’s CRM system using automated logins from multiple devices.

Botnets pose a serious risk—even to companies that aren’t the primary targets. Their infrastructure may be abused to support broader cyberattacks, spread malware, or damage the company’s reputation.

Botnet vs. related terms – What’s the difference?

• Botnet vs. malware
  Malware is the software that infects devices. A botnet is the network of those infected devices under external control.
• Botnet vs. DDoS
  DDoS (Distributed Denial of Service) is an attack method that uses a botnet to flood a target with traffic.
• Botnet vs. zombie počítač
  A zombie is a single device within a botnet. The botnet is the collection of all such devices working together.

Understanding these distinctions helps clarify how a simple infection can escalate into a coordinated cyberattack involving thousands of devices.

How to prevent your company from becoming part of a botnet

Recommended steps:

1. Keep all systems and software up to date with the latest patches.
2. Use firewalls and antivirus tools on endpoints and servers.
3. Monitor network traffic for unusual patterns—such as unknown IP communication.
4. Segment your network—separate critical systems, IoT devices, and standard workstations.
5. Use security tools like EDR (Endpoint Detection & Response) and SIEM for real-time detection and response.
6. Train employees—lack of awareness is often the gateway to infection.

Many businesses don’t realize they’re part of a botnet—their devices “work for the attacker” silently in the background. Proactive prevention, consistent monitoring, and strong security policies help maintain control of your infrastructure and avoid contributing to larger cyberattacks.