Botnet Examples (2024): The 6 Worst Attacks of All Time

By Tibor Moes / Updated: January 2024

Botnet Examples (2023): The 7 Worst Attacks of All Time

Botnets represent a significant cybersecurity threat, leveraging networks of compromised devices to launch widespread and disruptive attacks.

In this article, we will explore six of the most devastating botnet attacks in history, shedding light on their impact and the lessons learned from them.


A botnet is a network of internet-connected devices infected by malware that are controlled as a group without the owners’ knowledge, often to send spam or launch attacks.

  • Storm Botnet (2007): This botnet was known for its massive email campaigns. On one day in 2007, it sent a record 57 million emails.
  • Conficker (2008): A botnet that exploited Windows vulnerabilities, Conficker potentially controlled up to 10 million computers.
  • Zeus (2009): Specializing in financial theft, Zeus compromised over 74,000 FTP accounts on various high-profile websites.
  • Cutwail (2009): One of the largest spamming botnets, Cutwail used up to 2 million computers to send 74 billion spam messages a day.
  • Miraibotnet (2016): This botnet, targeting IoT devices, amassed around 500,000 compromised devices to launch DDoS attacks.
  • Emotet (2014-2020): Starting as a banking Trojan, Emotet evolved into a costly malware, with incidents costing up to $1 million each to remediate.

Don’t let your PC become part of botnet. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Botnet Examples

1. Storm Botnet (2007)

In 2007, the digital world witnessed a staggering display of the destructive power of botnets with the Storm Botnet. This cyber behemoth, on a particularly notorious day, orchestrated an email blitz like no other, sending out a record-breaking 57 million emails within a mere 24-hour period.

This figure, highlighted by Fast Company, underscores the immense scale and efficiency of the botnet. The Storm Botnet, named after the storm-related subject lines used in its emails, utilized these messages to spread malware and expand its network of infected computers.

This massive email surge not only demonstrated the botnet’s vast reach but also highlighted a grim reality of the internet era: how swiftly and stealthily malicious software can propagate, turning ordinary computers into unwitting accomplices in widespread cyber-attacks.

2. Conficker (2008)

The following year, 2008, saw the emergence of another formidable cyber threat: the Conficker botnet. According to F-Secure, a cybersecurity firm, Conficker potentially amassed a zombie army comprising nine to ten million compromised computers. This staggering number illustrates the sheer magnitude of the botnet’s infiltration.

Conficker, also known as Downup, Downadup, and Kido, exploited weaknesses in Microsoft Windows to infect computers and link them into a vast, covert network. The botnet’s capability to hijack millions of computers worldwide not only posed a significant threat to individual and organizational cybersecurity but also signaled a worrying evolution in the sophistication and scope of cybercriminal activities.

The scale of Conficker’s reach, silently converting everyday devices into components of a massive, controlled network, served as a wake-up call about the vulnerabilities inherent in our interconnected digital world.

3. Zeus (2009)

In 2009, the cyber world was rocked by the discovery of Zeus, a botnet that turned out to be far more insidious than previously imagined. According to The Tech Herald, an investigation in June 2009 revealed that Zeus had compromised over 74,000 FTP accounts.

This was not just a random array of websites; the list included high-profile names such as the Bank of America, NASA,, ABC, Oracle,, Cisco, Amazon, and BusinessWeek. This startling revelation shed light on the botnet’s sophisticated capabilities in infiltrating and extracting sensitive information from a diverse range of victims.

Zeus, primarily known for targeting online banking systems, demonstrated a frightening proficiency in bypassing security measures, leading to substantial financial and data breaches.

The exposure of its vast reach was a grim reminder of the escalating threats in the digital world, where even the most secure websites could fall prey to meticulously orchestrated cyber-attacks.

4. Cutwail (2009)

Meanwhile, 2009 also saw the notorious ascent of Cutwail, a different breed of botnet, known for its colossal spamming capabilities. Research from the University of California, Santa Barbara, and data from security provider MessageLabs painted a staggering picture of Cutwail’s operations.

The botnet, comprising an estimated 1.5 to 2 million individual computers, had the capacity to send a jaw-dropping 74 billion spam messages per day. To put this into perspective, that’s about 51 million spam emails every minute, accounting for 46.5% of the worldwide spam volume at the time. Cutwail’s spamming frenzy not only clogged inboxes across the globe but also served as a vehicle for distributing malware and phishing campaigns.

The botnet’s sheer size and output rate underscored a significant problem in the cyber world: the ease with which malicious actors could harness vast networks of unsuspecting computers to propagate digital chaos and disruption on an unprecedented scale.

5. Miraibotnet (2016)

In 2016, the cybersecurity world was introduced to a new kind of threat with the emergence of the Miraibotnet. Unlike its predecessors, Miraibotnet specifically targeted Internet of Things (IoT) devices. According to Netscout, the original Mirai botnet network comprised around 500,000 compromised IoT devices worldwide.

This was a groundbreaking and worrying development. Mirai’s strategy was to infect devices like digital cameras and DVR players, turning them into a formidable army of bots. This botnet, by exploiting vulnerabilities in IoT devices that were often overlooked in terms of security, showcased a frightening new frontier in cyber threats.

The scale of this network signified a seismic shift in the landscape of cyber-attacks, highlighting the growing vulnerability of the increasingly interconnected digital world where even seemingly harmless devices could be weaponized to launch massive Distributed Denial of Service (DDoS) attacks.

6. Emotet (2014-2020)

Emotet, operational from 2014 to 2020, represents another dark chapter in the annals of cybercrime. As reported by Heimdalsecurity, Emotet infections proved to be not only disruptive but also staggeringly expensive, with costs for state, local, tribal, and territorial (SLTT) governments reaching up to $1 million per incident for remediation.

This financial toll underscores the devastating impact of the botnet, which evolved from a simple banking Trojan to a sophisticated malware delivery service. Emotet’s modus operandi involved spreading through phishing emails and then installing other types of malware, leading to extensive data breaches, financial losses, and significant disruption of services.

The costs associated with Emotet incidents reflect the extensive resources required to address the aftermath of its attacks, from system restoration and security enhancements to loss mitigation.

Emotet’s legacy is a sobering reminder of the economic and operational devastation that sophisticated malware can inflict on public and private sectors alike.


The history of botnets, as exemplified by the Storm Botnet, Conficker, Zeus, Cutwail, Miraibotnet, and Emotet, vividly illustrates the evolving and persistent threat that these networks pose to digital security.

From sending billions of spam emails to stealing sensitive financial data and commandeering IoT devices for massive DDoS attacks, botnets have demonstrated their capacity to cause widespread disruption and significant financial damage. These examples underscore the critical need for constant vigilance and robust security measures in the face of ever-advancing cyber threats.

In light of these threats, particularly for users of Windows 11, investing in reliable antivirus software has never been more crucial. Brands like Norton, Avast, TotalAV, Bitdefender, McAfee, Panda, and Avira offer advanced protection against a wide range of cyber threats, including those posed by botnets.

These antivirus solutions provide real-time defense mechanisms, regular updates to tackle the latest malware, and comprehensive system scans to detect and neutralize threats. By choosing a reputable antivirus product, individuals and organizations can significantly bolster their defenses against the sophisticated and diverse threats presented by modern botnets.

This investment in cybersecurity is not just a measure of protection; it is an essential component of responsible digital stewardship in an increasingly interconnected world.




Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor has tested 39 antivirus programs and 30 VPN services, and holds a Cybersecurity Graduate Certificate from Stanford University.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

You can find him on LinkedIn or contact him here.