What is a Botnet Attack in Cyber Security? How to Prevent It?

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By Muhammad Hussain

Botnet attack is among the most widespread and severe threats in cybercrime, impacting large institutions, government organizations, and nearly every entity associated with the internet.

Have you ever come across posts on social networks or received emails in your name that you never sent? Is your computer running slowly? Do you find your screen inundated with pop-up ads? All of these issues could be symptoms of infection or might indicate that your computer is part of a botnet attack. Botnets are networks of hijacked computer devices utilized to carry out cyberattacks.

The following graph illustrates the most prevalent botnets worldwide in 2021.


In this article, we will discuss what a botnet attack is and how to prevent it. 

What is a Botnet Attack?

A botnet, often referred to as a network of infected computers or “zombies,” is a collection of malware-infected machines that an attacker can control to execute various activities. These activities may occur without the knowledge of the computer owners.

Botnet attacks facilitate cybercriminals in gaining control over these infected computers, allowing them to target servers, corporate websites, or other devices.

Botnets serve various nefarious purposes, including:

  • Propagating malware and exfiltrating sensitive information.
  • Generating and directing substantial volumes of traffic toward a targeted website or server.
  • Collecting sensitive data, such as personal or financial information.
  • Covertly mining cryptocurrencies using infected computers.
  • Distributing large quantities of spam emails.

How Does Botnet Spread?

Botnets spread by exploiting vulnerabilities and human behavior. Botnets are created and utilized by malicious actors, often with the intent of carrying out various cybercriminal activities.

Here are some common ways in which botnets can spread:

  • Cybercriminals use spam emails, which may contain links or attachments that execute malware, spread infection, and connect it to botnets.
  • Malvertisements can deliver malware to users when a user clicks on these ads.
  • Cybercriminals use human psychology to trick users into downloading and running malware. This includes fake software updates or fraud offers.
  • Some botnets spread through infected USB drives; when a user inserts an infected drive into their computers, it automatically infects the system.
  • Botnets can target vulnerable Internet of Things (IoT) devices and embedded systems such as routers, cameras, and other devices.

Types Of Botnet

Botnet comes in various forms, and each is designed for a specific purpose. They carry out different types of malware activities. 

A botnet can be used to conduct many types of attacks, including:


1. DDoS Botnet

DDoS (Distributed Denial of Service) botnets employ massive amounts of traffic to disrupt networks. The operator of such a botnet infects a considerable number of devices with malware. To facilitate their activities, the attacker employs a Command and Control (C&C) infrastructure for communication and coordination. Preparation for a DDoS attack entails selecting a target, devising a strategy, and configuring the attack. Subsequently, the attacker issues commands to compromised devices, instructing them to flood the target with traffic.

DDoS attacks can cause disruptions to online services, affecting a company’s operations, reputation, revenue, and customer trust, and can be short-lived or sustained.

2. Phishing

Phishing is a cyberattack technique used to steal valuable information and commit financial fraud by gaining unauthorized access to accounts. The attacker uses fraudulent emails, messages, or websites to deceive people into revealing their personal information, account details, or passwords. 

Phishing messages often create a sense of urgency, fear, or curiosity to prompt the recipient to take immediate action, and emails contain malicious links and attachments that install malware.

3. Spam Botnet

Spam botnets are networks of compromised computers used by cybercriminals to send out spam emails. These emails contain unsolicited and often fraudulent or malicious content. Spambots use email addresses to create accounts and send spam. 

To accomplish this, attackers convert a substantial number of computers, servers, and other devices into zombies through malware infections. They wield control over the infrastructure for botnet management, allowing them to continually alter tactics to evade detection.

4. Zbot

Zbot is also known as Zeus, it is a banking Trojan used by cybercriminals to steal sensitive financial information such as credit card numbers, banking details, and other sensitive information. 

Zbot spreads through malicious email attachments, drive-by downloads, and exploit kits and has keylogging capabilities to record keystrokes and capture data from web forms. Infected devices become part of the botnet and are controlled by attackers. 

5. Mobile Botnet

Mobile botnets are networks of compromised mobile devices controlled by cybercriminals, used to send spam, distribute malware, and conduct DDoS attacks. These smartphones or tablets are infected with malware that allows the attackers to remotely control them without the user’s knowledge or consent. 

Mobile botnets can be used to send malicious links and phishing content, leading to financial losses and data theft. Users should take preventive measures, including updating devices, avoiding untrusted apps, and using reputable security software.

Signs Your Computer is a Part of a Botnet Attack

Detecting whether your computer is infected or not could be challenging. However, several signs might indicate that your computer is attacked by the botnet. 

Take action immediately if you notice any of the following signs:

  • If your computer suddenly becomes slower, it could be a sign that it is part of the botnet.
  • Increased data usage is a sign that your computer is engaged in activities like spamming, or other malicious actions. 
  • If you notice new software, browser extensions, or plugins that you didn’t install, your computer might be associated with a botnet.
  • Malware activity can cause unexpected crashes, freezes, and error messages.
  • Malware can bypass security software to remain undetected.
  • If you find unauthorized access to online accounts, it can indicate a botnet attack.

How to Prevent Botnet Attack?

Preventing a botnet attack involves good cyber security practices. Users can install bot detector software such as SEON, DataDome, Arkose Labs, Cloudflare, and ClickGuard.

Here are some preventive measures to protect your computers against botnet attacks:

  • Regularly update your operating system, applications, and software to patch vulnerabilities.
  • Install and update antivirus and antimalware software to protect against threats.
  • Create strong and unique passwords and use different passwords for different accounts.
  • Only download software from trusted sources.
  • Enable a firewall to monitor and block unauthorized connections.
  • Back up your important data regularly to protect against ransomware.
  • Users can use biometric authentication methods such as fingerprints or face identification.
  • Make sure your employees know how to protect the network from spam, phishing, and insecure links.

Prevention is a continuous effort. Consistently implement security measures to reduce the risk of botnet attacks and other cyber security threads.


Botnet attacks pose significant risks, including data breaches, financial losses, and critical services and infrastructure disruptions. Botnet attacks are a reminder of the constantly evolving nature of cyber security threats. To foster a safer digital environment, it’s imperative to invest in technology, bolster security practices, encourage information sharing, and promote collaboration among stakeholders. 

The cyber security community must remain at the forefront of innovation, developing new tools and strategies to proactively combat emerging threats. Only through collective effort and adaptability can we effectively safeguard our digital world.

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How are botnet attacks prevented?

Botnet attacks can be prevented by technical measures, best security, and user education. Regularly update and install bug fixes for your software. Never click on spam emails, attachments, or links.

How to clean a botnet?

Install antivirus software to detect and remove malware that is used to create botnets.

How do hackers create botnets?

Botnets are created by infecting computers with malicious software in the form of a trojan horse virus. They are used to launch DDoS attacks, distribute malware, send spam, and steal data.