Trojan Horse Examples (2024): The 6 Worst Attacks Ever

By Tibor Moes / Updated: January 2024

Trojan Horse Examples (2023): The 6 Worst Attacks Ever

In the ever-evolving landscape of cybersecurity, Trojan horse attacks represent a significant and persistent threat to individuals and organizations alike.

This article delves into the history of six of the most devastating Trojan horse attacks, offering insights into their mechanisms, impacts, and the lessons learned from these cyber incursions.


  • ILOVEYOU (2000): This worm masqueraded as a love letter, rapidly infecting millions of computers worldwide. It infected over ten million Windows PCs starting from May 5, 2000.
  • Zeus (2009): A powerful Trojan that targeted financial information, Zeus compromised thousands of FTP accounts including those of major companies. Over 74,000 FTP accounts on high-profile sites were compromised by June 2009.
  • CryptoLocker (2013): This ransomware encrypted users’ files and demanded payment for their release. Between 200,000 to 250,000 computers were infected, with operators extorting around $3 million.
  • Emotet (2014): Initially a banking Trojan, Emotet evolved to deliver other malware and caused significant financial damage. It has cost governments up to $1 million per incident to remediate.
  • Dyre (2014): Dyre targeted banking credentials, showing a marked increase in infection rates and financial theft. Infections rose from 500 to nearly 3,500 instances, with over $1 million stolen from enterprises.
  • BlackEnergy (2015): Initially a simple Trojan, BlackEnergy evolved to disrupt critical infrastructure, notably in Ukraine. It left about 1.4 million people without electricity for several hours in Ukraine.

Don’t become a victim of a trojan horse. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Trojan Horse Examples

1. ILOVEYOU (2000)

In the early days of May 2000, a seemingly harmless email began circulating with the subject line “I LOVE YOU.” What appeared as a digital note of affection was, in fact, one of the most virulent computer worms of its time. According to, the ILOVEYOU worm rapidly infected over ten million Windows personal computers globally, beginning its spread on May 5, 2000.

The worm exploited human curiosity and trust, using a simple email attachment to infiltrate and replicate across networks. Its reach was not only vast but also alarmingly swift, showcasing the vulnerabilities in personal and corporate cybersecurity practices at the dawn of the 21st century.

The ILOVEYOU incident serves as a stark reminder of how digital trust can be exploited and the profound impact of cyber threats on a global scale.

2. Zeus (2009)

Fast forward to 2009, and the cybersecurity world witnessed the emergence of Zeus – a Trojan horse that epitomized the growing sophistication of cybercriminal tactics.

As reported by, in June 2009, it was discovered that Zeus had compromised over 74,000 FTP accounts, infiltrating the online defenses of high-profile companies such as Bank of America, NASA,, ABC, Oracle,, Cisco, Amazon, and BusinessWeek.

This malware was not just a tool for data theft; it was a full-fledged operation that targeted the very foundation of corporate and financial security. The Zeus Trojan showcased the escalating arms race in cybersecurity, where the stakes were not just personal information but also the integrity of critical corporate and governmental infrastructures.

3. CryptoLocker (2013)

In 2013, the digital world was introduced to a new form of cyber terror: ransomware. CryptoLocker, a formidable player in this domain, emerged as a ransomware Trojan that held personal files hostage for a ransom.

According to, by mid-December of that year, between 200,000 to 250,000 computers were infected by CryptoLocker. The Trojan demanded payment in Bitcoin, exploiting the anonymity of digital currency to carry out its extortion. The operators behind CryptoLocker demonstrated a chilling efficiency, managing to extort an estimated total of around $3 million from victims.

This attack not only highlighted the vulnerability of personal data but also underscored the growing threat of ransomware in the digital age, where data encryption could be weaponized for financial gain.

4. Emotet (2014)

The following year, in 2014, the cybersecurity landscape faced another formidable challenge with the advent of Emotet. Initially a banking Trojan, Emotet evolved into a sophisticated malware delivery service. reported that Emotet infections have cost state, local, tribal, and territorial (SLTT) governments up to $1 million per incident to remediate.

This malware was particularly notorious for its ability to evade standard antivirus detection, making it a persistent threat. Emotet’s impact extended beyond financial losses; it compromised the security of government systems, posing a threat to public sector operations.

The case of Emotet is a stark reminder of the continuous evolution of cyber threats and the escalating costs associated with combating these sophisticated attacks.

5. Dyre (2014)

In the latter part of 2014, the cybersecurity community faced a significant surge in the activity of Dyre, a notorious banking Trojan. reported that in October 2014, the IBM Trusteer team observed a dramatic spike in Dyre infections, escalating from 500 instances to nearly 3,500.

This malware specialized in stealing banking credentials, and IBM Security uncovered an active campaign using a variant of Dyre malware that successfully siphoned more than $1 million from targeted enterprise organizations.

Dyre’s rapid proliferation and financial impact underlined the escalating threat posed by banking Trojans. They no longer just targeted individual consumers; they had evolved to launch sophisticated attacks against large organizations, posing a serious threat to corporate financial security.

6. BlackEnergy (2015)

The year 2015 marked a pivotal moment in cyber warfare with the BlackEnergy attack. According to, a significant incident occurred in Ukraine, where approximately 1.4 million people were plunged into darkness for several hours due to a cyberattack.

BlackEnergy, originally designed as a relatively simple Trojan, had evolved into a sophisticated tool capable of carrying out large-scale infrastructure attacks. This incident in Ukraine was particularly alarming as it demonstrated the potential of cyberattacks to cross over from the digital realm into causing real-world, physical disruptions.

The BlackEnergy attack not only disrupted daily life for millions but also signified a new era in cyber threats, where critical infrastructure became a prime target.


As we have seen through these examples, Trojan horse attacks pose a significant and evolving threat in the digital landscape. From the widespread infection caused by ILOVEYOU to the sophisticated financial and infrastructural disruptions by Zeus, CryptoLocker, Emotet, Dyre, and BlackEnergy, the impact of these attacks is both far-reaching and deeply concerning. These incidents underscore the importance of vigilance and proactive measures in cybersecurity.

In light of these threats, the importance of robust antivirus solutions, especially for Windows 11 users, cannot be overstated. Brands like Norton, Avast, TotalAV, Bitdefender, McAfee, Panda, and Avira offer comprehensive protection against such malware.

Investing in these antivirus programs provides not just real-time protection against known threats, but also employs advanced technologies to detect and neutralize emerging threats. With cybercriminals constantly evolving their tactics, having a reliable antivirus is an essential line of defense for safeguarding personal and organizational data.




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.