What is a Botnet? AI-Driven Threats, IoT Exploits, and Prevention Strategies for 2025

Botnets are one of the most dangerous cyber threats in 2025, evolving with AI-driven automation and cloud-based command systems. They target businesses, individuals, and governments, exploiting IoT devices, real-time applications, and remote work environments. 

In 2024, India saw a 115% surge in cyberattacks during Q2 compared to the previous year, highlighting the growing threat. 

With ransomware-as-a-service and large-scale DDoS attacks on the rise, organizations face financial losses, data breaches, and operational disruptions. This guide breaks down what a botnet is, explores botnet architecture, and examines types of botnet attacks. 

What is a Botnet and Why is it a Cybersecurity Threat?

A botnet is a network of compromised computers, known as “bots” or “zombies,” that are controlled remotely by a cybercriminal, often called a botmaster. These infected devices—ranging from personal computers and smartphones to IoT gadgets—operate without their owners’ knowledge, executing malicious tasks on a massive scale. 

Botnets are a major cybersecurity threat due to their ability to automate and amplify cyberattacks, making them a powerful tool for cybercriminals. 

The major cybersecurity threats from botnets are:

• DDoS Attacks – Botnets overwhelm websites or networks with traffic, causing downtime.
  • Impact: Disrupts operations, cripples online services, and leads to financial losses.
  • Example: The Mirai botnet shut down major sites like Twitter and Netflix in 2016.
• Credential Theft & Financial Fraud – Keyloggers and malware steal login credentials and banking data.
  • Impact: Identity theft, drained bank accounts, and stolen corporate data.
  • Example: TrickBot targeted financial institutions, stealing banking credentials.
• Spam & Phishing Campaigns – Botnets send mass spam emails with malware or scam links.
  • Impact: Spreads ransomware, facilitates fraud, and tricks users into sharing sensitive data.
  • Example: Necurs botnet sent 5 million spam emails per hour.
• Ransomware Distribution – Botnets spread ransomware that encrypts files for ransom.
  • Impact: Business disruptions, financial losses, and data inaccessibility.
  • Example: Ryuk ransomware, spread via TrickBot, targeted hospitals and enterprises.
• Cryptojacking – Botnets hijack devices to mine cryptocurrency.
  • Impact: Slow performance, high energy costs, and hardware damage.
  • Example: Smominru botnet infected 500,000 devices to mine Monero.

Botnets rely on complex networks to launch large-scale cyberattacks while evading detection. Understanding their structure is key to disrupting them.

How Do Botnet Architecture Operate? Key Components and Mechanisms

Botnets operate through either a hierarchical or decentralized structure, enabling cybercriminals to control vast numbers of infected devices. 

In hierarchical models, all bots connect to a central Command & Control (C&C) server, making it easier for hackers to issue commands but also easier for security experts to dismantle. 

Decentralized botnets, often peer-to-peer (P2P), distribute control among compromised devices, making them harder to track and shut down. Some botnets use domain generation algorithms (DGA) to create new command domains dynamically, preventing security teams from cutting off their communication channels.

Key Components of a Botnet

• Bots (Zombie Devices) – Infected computers, IoT devices, or servers that carry out malicious activities.
• Bot Herder (Attacker) – The cybercriminal controlling the botnet, often remotely.
• Command & Control (C&C) Servers – Infrastructure used to send instructions to compromised devices.
• Communication Protocols – Methods such as HTTP, P2P, or DNS tunneling that enable command transmission.
• Attack Execution Mechanisms – Techniques used to launch cyberattacks like DDoS, ransomware, and credential theft.

Botnets operate in five key stages, from infection to execution and evasion.

1. Infection Stage: Spreading the Botnet Malware

This is how a device first becomes part of a botnet. Cybercriminals use:

• Phishing emails that trick users into downloading malware.
• Exploits targeting software vulnerabilities in unpatched systems.
• Drive-by downloads that install malware when a user visits an infected website.
• IoT device hijacking, where weak passwords and outdated firmware make smart devices easy targets.

How to Detect It:

• Sudden system slowdowns or unusual network traffic.
• Unexpected changes in system settings or unauthorized software installations.
• Frequent security warnings or antivirus alerts.

Why It’s Dangerous:

• Once infected, the device can receive commands without the owner’s knowledge.
• The malware often operates silently, making it difficult to detect before damage occurs.

Also Read: 100 Must-Know Cybersecurity Terms for 2025

2. Command & Control (C&C) Communication: How Hackers Control Botnets

Once infected, the bot connects to the attacker’s C&C infrastructure. Hackers use:

• Centralized C&C servers where all bots report to a single command center.
• Decentralized (P2P) communication, where bots relay instructions among themselves.
• Fast-flux networks, which rapidly change IP addresses and domains to avoid detection.

How to Detect It:

• Unusual outbound network requests to suspicious or unknown IPs.
• Consistent traffic to changing domain names, a hallmark of fast-flux botnets.
• Increased system resource usage, even when idle.

Why It’s Dangerous:

• Bot herders can instantly launch large-scale attacks, from ransomware deployment to credential theft.
• Advanced botnets use encrypted communication to avoid detection by security tools.

3. Execution & Coordination: Carrying Out Cyberattacks

After receiving instructions, botnets engage in malicious activities such as:

• DDoS attacks, flooding networks with fake traffic to shut them down.
• Credential theft, capturing keystrokes or scraping login details.
• Spamming and phishing, using infected devices to send fraudulent emails.
• Ransomware deployment, encrypting files and demanding payment.

How to Detect It:

• Unusual spikes in outgoing traffic, indicating mass spam or attack execution.
• Strange background processes consuming high CPU or memory.
• Unexpected login attempts on financial accounts or cloud services.

Why It’s Dangerous:

• Attacks can target individuals, businesses, or entire industries.
• Financial losses, data breaches, and reputational damage are common consequences.

Also Read: Top 7 Cybersecurity Threats & Vulnerabilities

4. Propagation & Evolution: Expanding the Botnet

Botnets are designed to grow and adapt, using:

• Self-replicating malware that spreads across local and global networks.
• Lateral movement techniques, where bots infect additional devices in the same network.
• AI-driven evasion, where botnets alter their behavior based on security defenses.

How to Detect It:

• A single infected device in a network can lead to multiple compromised systems.
• Increased inter-device traffic within corporate networks without a known source.
• Security tools detecting multiple instances of the same malware spreading rapidly.

Why It’s Dangerous:

• Every new bot strengthens the botnet, making takedowns harder.
• Advanced botnets use polymorphic malware, changing their code to avoid signature-based detection.

Also Read: Adversarial Machine Learning: Concepts, Types of Attacks, Strategies & Defenses

5. Detection & Mitigation: Stopping a Botnet Attack

• Behavioral analysis – Identifying irregular network activity rather than relying on static malware signatures.
• Network traffic monitoring – Blocking suspicious outbound connections.
• Endpoint protection – Using AI-driven antivirus software to detect new threats.
• Botnet takedowns – Security teams work with ISPs and law enforcement to dismantle C&C servers.

How to Detect It:

• Frequent system crashes or unauthorized remote connections.
• A sudden inability to access security-related websites (a sign of malware interference).
• Devices running at maximum capacity even when idle.

Why It’s Dangerous:

• Without proper mitigation strategies, a single infection can compromise an entire organization.
• Attackers often use botnets for long-term persistence, keeping access even after initial removal attempts.

Also Read: Introduction to Cyber Security: A Complete Beginner’s Guide

Understanding the architecture of a botnet is just the first step. To effectively combat these threats, we must examine how botnets evolve through different lifecycle stages, from infection to large-scale attacks.

What are the Key Stages of the Botnet Lifecycle?

Botnets evolve through distinct stages, from initial infection to large-scale attack execution and long-term survival. Each phase strengthens their control, making detection and mitigation increasingly difficult.

Stage 1: Identifying and Infecting Vulnerable Systems

• Target Selection: Botnets scan millions of devices worldwide, looking for outdated security patches, weak passwords, and unprotected systems. A small business running an unpatched web server or a smart home device with factory-default credentials can be prime targets.
• Infection Methods:
  • A phishing email disguised as a security update tricks employees into downloading malware that silently turns their workstations into bot-controlled nodes.
  • Unsecured IoT devices, like security cameras or smart thermostats, are hijacked through default login credentials, providing attackers with entry points into larger networks.
  • Malware is embedded in free software downloads, infecting users who install what appears to be a useful application.
• Harmful Impact:
  • Devices become part of a larger malware distribution network, unknowingly spreading infections to others.
  • Infected systems may display no immediate signs, allowing the botnet to grow undetected for months.
• Detection Signs:
  • Unexplained spikes in network traffic, even during non-working hours.
  • Slow device performance, as background processes execute unauthorized tasks.

Stage 2: Establishing Communication with the Botmaster

• C&C Connection Setup:
  • Once infected, devices reach out to command servers through encrypted channels, ensuring persistent control.
  • Some botnets rely on peer-to-peer (P2P) networking, where bots communicate directly with each other, eliminating a single point of failure.
  • Others use Fast-Flux DNS, constantly changing their command addresses to prevent authorities from blocking them.
• Harmful Impact:
  • A hijacked cloud server in a financial firm quietly transmits stolen credentials to a remote attacker without triggering security alarms.
  • A group of compromised home routers forms a hidden botnet that receives daily updates on new attack targets.
• Detection Signs:
  • Devices making frequent outbound connections to unknown or rapidly changing domains.
  • Firewalls flagging encrypted traffic to unrecognized ports, which may indicate stealthy communication with an attacker-controlled server.

Stage 3: Executing Commands, Spreading Malware, and Launching Attacks

• Attack Execution:
  • A botnet army is instructed to flood a major e-commerce platform with traffic, bringing its website down during a peak shopping season.
  • Infected devices silently collect and forward keystrokes and login details, leading to widespread identity theft and corporate espionage.
  • A finance department’s computers suddenly display ransomware messages, demanding cryptocurrency payments after being unknowingly compromised.
• Self-Replication & Malware Distribution:
  • A compromised office printer unknowingly spreads malware to all connected systems, expanding the botnet’s reach.
  • A social media account taken over by a botnet starts mass messaging phishing links to unsuspecting contacts.
• Harmful Impact:
  • A single infected endpoint can lead to a full-scale breach within a company, exposing sensitive data.
  • Attackers can sell access to infected networks on the dark web, leading to further security risks.
• Detection Signs:
  • A sudden surge in unauthorized login attempts from unusual locations.
  • Email accounts sending spam messages without the user’s knowledge.

Stage 4: Expanding the Botnet and Avoiding Detection

• Growth & Adaptation:
  • A compromised smart TV in a home network acts as a gateway for infecting other connected devices.
  • Self-replicating malware moves through a university’s unsecured Wi-Fi, turning student laptops into botnet-controlled systems.
  • A botnet updates its encryption techniques, making traditional antivirus software ineffective.
• Advanced Evasion Tactics:
  • A botnet changes its malware signatures daily, making detection by traditional security tools nearly impossible.
  • Attackers use legitimate cloud services as relay points, disguising botnet traffic as normal user activity.
• Harmful Impact:
  • Organizations spend millions in mitigation after botnets remain undetected for months, causing irreversible damage.
  • A public-sector agency unknowingly leaks classified data due to botnet-activated spyware.
• Detection & Prevention:
  • AI-based behavioral monitoring detects irregular access patterns, even from seemingly safe sources.
  • Zero-trust policies limit lateral movement, reducing botnet spread within networks.

Also Read: What is End-to-End Encryption? How It Works, and Why We Need It

Each stage of the botnet lifecycle strengthens its ability to launch large-scale cyberattacks. 

Now, let’s explore the different types of botnets and their impact on cybersecurity.

Different Types of Botnet Attacks and Their Impact

Botnets vary in structure, purpose, and attack methods. Some focus on disrupting online services, while others steal sensitive data or exploit system resources. These attacks affect businesses, individuals, and even national security by compromising digital infrastructure and financial systems.

1. Centralized Botnets (Single C&C Server)

• Operate through a single command server that directs all infected devices.
• Easy for botmasters to manage but also vulnerable to takedown if the server is shut down.
• Impact: Once detected, entire botnets can be dismantled quickly, but they remain powerful if undiscovered.

2. Decentralized (P2P) Botnets

• Bots communicate directly with each other, eliminating a single point of failure.
• Harder to track and shut down since commands are relayed across multiple infected devices.
• Impact: More resilient against law enforcement actions, making them long-term cyber threats.

3. Hybrid Botnets (Centralized + P2P)

• Combine centralized efficiency with P2P resilience, balancing control and stealth.
• Can switch to decentralized mode if a C&C server is taken down.
• Impact: More adaptive and persistent, making them extremely difficult to eliminate.

4. IoT Botnets (Targeting Smart Devices)

• Infiltrate smart home devices, security cameras, and routers with weak security settings.
• Exploit default credentials and outdated firmware to take over devices.
• Impact: Create massive botnets for DDoS attacks, spying, and network infiltration.

5. DDoS Botnets (Distributed Denial-of-Service Attacks)

• Overwhelm websites and servers with fake traffic, causing downtime and service disruption.
• Often rented as "DDoS-for-hire" services on the dark web.
• Impact: Cripples businesses, government services, and financial institutions, leading to millions in losses.

6. Spam Botnets (Mass Email Spam Campaigns)

• Hijack email accounts to send millions of spam messages, spreading malware and phishing links.
• Used for fraud, scams, and spreading ransomware.
• Impact: Lowers email security, increases phishing success rates, and damages reputations of affected organizations.

7. Cryptojacking Botnets (Mining Cryptocurrency Illegally)

• Exploit system resources to mine cryptocurrency without user consent.
• Often target cloud services and high-performance computing environments.
• Impact: Slows down devices, increases energy costs, and reduces system lifespan.

8. Banking Botnets (Financial Credential Theft)

• Infect devices with keyloggers and spyware to steal banking credentials.
• Used in fraudulent transactions, identity theft, and account takeovers.
• Impact: Direct financial losses, compromised accounts, and regulatory fines for businesses failing to protect user data.

Also Read: Cyber Security in Banking: Challenges and Security Strategies for 2025

Knowing how botnets execute attacks gives deeper insight into their real-world impact. Let’s break down the most common botnet attack methods and how they work.

Common Types of Botnet Attacks

Botnets are used to automate large-scale cyberattacks, targeting individuals, businesses, and critical infrastructure. If you're wondering what a botnet is and how it poses a threat, examining these attacks will provide clear answers.

Below is an overview of how these attacks operate, their consequences, and prevention methods.

Also Read: What is Cyber Crime? Types, Example, How to Prevent?

Examining real-world botnet attacks reveals the true scale of damage they can cause and the security measures they have forced industries to adopt.

Real-World Examples of Botnet Attacks and Their Effects

Botnets have left a lasting impact on global cybersecurity, demonstrating how large-scale, automated cyberattacks can disrupt economies, businesses, and even national infrastructure. These real-world incidents demonstrate what a botnet is in action and why it remains one of the most dangerous cybersecurity threats today.

1. Mirai Botnet (2016) – The IoT Takeover

In 2016, a group of attackers weaponized insecure Internet of Things (IoT) devices like routers, security cameras, and DVRs to create Mirai, one of the most notorious botnets in history. By exploiting weak default passwords, Mirai infected hundreds of thousands of devices, turning them into a massive botnet army.

• The Attack: The botnet launched an unprecedented DDoS attack against Dyn, a major DNS provider, shutting down major websites like Twitter, Netflix, and PayPal.
• Impact: The attack caused widespread internet outages across the U.S., revealing how poorly secured IoT devices could be manipulated on a massive scale.
• Aftermath: Companies implemented stricter IoT security policies, and manufacturers were pressured to stop using default login credentials on consumer devices.

2. Emotet Botnet (2014–Present) – The Shape-Shifting Threat

What started as a banking trojan quickly evolved into one of the most resilient botnets, specializing in spreading malware and ransomware to high-profile targets, including governments and businesses worldwide.

• The Attack: Emotet spread via phishing emails disguised as invoices, shipping notifications, and even COVID-19 updates. Once a system was infected, the botnet downloaded additional malware, allowing attackers to steal financial data or install ransomware.
• Impact: Government agencies and corporations suffered data breaches, financial losses, and operational disruptions due to Emotet's ability to spread rapidly.
• Aftermath: In 2021, law enforcement temporarily took down Emotet’s infrastructure, but it resurfaced in 2022, showing how botnets can rebuild and evolve even after being dismantled.

3. Conficker Botnet (2008) – The Malware That Wouldn’t Die

Conficker infected millions of Windows computers worldwide, including military networks and critical infrastructure. Despite multiple takedown attempts, it continued to spread for years, proving the persistence of well-designed botnets.

• The Attack: Conficker exploited a Windows vulnerability (MS08-067) to infiltrate systems. It disabled security updates and antivirus software, making infected machines nearly impossible to clean.
• Impact: It disrupted military operations, infected hospitals, and even government agencies, forcing emergency cybersecurity responses.
• Aftermath: Microsoft issued an urgent security patch, and organizations began enforcing mandatory updates and network segmentation to prevent large-scale infections.

4. Zeus Botnet (2007–2010) – The King of Banking Fraud

Zeus was designed with one purpose—to steal banking credentials and drain accounts worldwide. It infected over 3.6 million devices in the U.S. alone, causing billions in financial losses.

• The Attack: The botnet used keyloggers and form-grabbing malware to record users' banking details when they logged into financial accounts.
• Impact: Stolen credentials were used to make fraudulent transactions, affecting both individuals and corporations. Many victims never recovered their funds.
• Aftermath: Authorities dismantled Zeus’s infrastructure, but its code was leaked online, leading to the creation of new, more advanced banking trojans like GameOver Zeus and Dridex.

5. Rustock Botnet (2006–2011) – The Spam King

Rustock operated quietly for years, yet at its peak, it was responsible for nearly half of all spam emails sent globally—that’s billions of fraudulent messages per day.

• The Attack: Rustock hijacked thousands of computers, using them to send spam emails promoting fake pharmaceuticals and distributing malware.
• Impact: It flooded email servers, increased phishing attacks, and drove up cybersecurity costs for businesses forced to filter out massive amounts of junk mail.
• Aftermath: In 2011, Microsoft and law enforcement took down Rustock’s C&C servers, setting a major legal precedent for botnet takedowns.

Also Read: Top 21 Ethical Hackers in India: Challenges, Future, and More

Understanding how botnets operate and the damage they cause is essential in preventing future cyber threats. Up next, we’ll explore how organizations and individuals can detect and defend against botnet attacks in 2025.

How to Detect Botnet Infections? Warning Signs & Tools

Detecting botnet infections early is crucial to prevent large-scale cyberattacks and protect personal and corporate data. Many botnets operate silently, making them difficult to detect without actively monitoring system behavior and network activity. 

Below, we cover the key warning signs of a botnet infection and the essential tools to identify and prevent them.

Botnets often exploit compromised devices without the owner's knowledge. If you notice these warning signs, your device may already be under botnet control:

Also Read: 30 Best Cyber Security Projects To Work On in 2025

Detecting a botnet infection is only half the battle—preventing botnets from infiltrating your systems in the first place is the best defense. 

Here’s how you can fortify your security against botnet attacks.

How to Prevent a Botnet Attack? Key Insights

Botnets exploit weak security measures, making proactive defense strategies essential for individuals and organizations. Implementing multiple layers of protection reduces the risk of device compromise, data theft, and large-scale cyberattacks.

Below are essential strategies to minimize botnet risks:

Also Read: Cyber Security Threats: What are they and How to Avoid

Preventing botnet attacks requires strong cybersecurity skills and hands-on expertise. upGrad equips you with the knowledge needed to stay ahead of evolving cyber threats.

How Can upGrad Help You Build Cybersecurity Expertise?

With cybersecurity attacks becoming more sophisticated, professionals must master network security, ethical hacking, and threat detection to protect organizations from threats like botnets, ransomware, and phishing. 

Understanding cyberattack methods, prevention strategies, and risk mitigation is essential for securing critical systems.

upGrad’s 200+ cybersecurity courses provide hands-on training, real-world case studies, and in-depth knowledge on detecting, preventing, and responding to modern cyber threats.

Here are  free courses to strengthen your cybersecurity skills before pursuing advanced certifications:

• Fundamentals of Cybersecurity
• Programming with Python: Introduction for Beginners
• Basics of Inferential Statistics
• Linear Algebra for Analysis

upGrad also offers executive diplomas and PG certifications to advance your cybersecurity career:

• Executive Diploma in Data Science & AI with IIIT-B
• Post Graduate Certificate in Data Science & AI (Executive)

You can also checkout the following certifications from upGrad Knowledgehut:

• CISSP® Certification (Certified Information Systems Security Professional)
• Azure Solutions Architect
• AWS Certified Solutions Architect

Not sure where to start or which cybersecurity skills are in demand? Schedule a free personalized career counseling session or visit your nearest upGrad offline center to explore the right program for you!

Boost your career with our popular Software Engineering courses, offering hands-on training and expert guidance to turn you into a skilled software developer.

Explore our Popular Software Engineering Courses

Master in-demand Software Development skills like coding, system design, DevOps, and agile methodologies to excel in today’s competitive tech industry.

In-Demand Software Development Skills

Stay informed with our widely-read Software Development articles, covering everything from coding techniques to the latest advancements in software engineering.

Read our Popular Articles related to Software