What is a Trojan horse attack?

What is a Trojan horse attack?

8 mins read12.8K Views Comment
Anshuman Singh
Senior Executive - Content
Updated on Apr 16, 2024 17:08 IST

A cyber attack is an attack to stop computers, steal data, or launch additional attacks using a compromised computer system.


Cybersecurity refers to protecting systems, networks, and programs from digital attacks. These cyberattacks aim to gain access to, alter, or destroy sensitive information, extort money from users, or disrupt normal business processes. The Trojan horse is one such method.

You can also explore – What is an Ethical Hacker?

In this article, we will be discussing the Trojan horse attack in detail. But, before moving any further, let’s go through the topics that we will be covering in this blog:

What is the significance/meaning of the Trojan horse?

During the Trojan War, the Greeks created a massive hollow wooden horse to gain entry into Troy. The Greeks sailed to the nearby island, pretending to escape from the war, leaving behind a vast horse structure. The people of Troy were convinced that the horse was an offering to Athena (goddess of war) that would make Troy impregnable. Despite the warnings, the horse was led through the city gates. Greek warriors emerged from it that night and opened the gates, allowing the Greek army to return.

The figure shows a Trojan horse.

The word Trojan horse refers to externally introduced subversion. In the early days, the term “Trojan horse” was applied to seemingly harmless computer codes written in order to harm or disrupt computer programming or collect sensitive information

What is a Trojan horse?

Trojans are malicious programs that appear to perform one function but perform another. Attackers can disguise Trojans as free software, videos, or music, or they could appear to be legitimate advertisements. They can also use Trojans as standalone tools or as a platform for other malicious activity.

Attackers, for example, use trojan downloaders to deliver future payloads to a victim’s device. Hackers can use Trojan rootkits to remain active on a user’s device or a corporate network.

Examples of a Trojan horse

Some well-known examples of Trojans are:

Zeus/Zbot: The Zeus (Zbot) trojan is malware software that targets Microsoft Windows-based devices. It infiltrates devices by generating a trojan horse, which appears to your system as a legitimate file but is malware that can grant third-party access to your system.

Rakhni Trojan: Rakhni is a high-risk Trojan that can spread through spam emails. This Trojan infects devices by delivering ransomware, also known as a crypto jacked tool, which enables the hacker to use a device to mine cryptocurrency.

Kaspersky products detected Rakhni in Russia, Kazakhstan, Ukraine, Germany, and India. The malware primarily spreads through spam email attachments. For example, the sample examined by experts was disguised as a financial document. This implies that cybercriminals are interested principally in incorporating “clients.”

Tiny Banker: Tiny Banker allows hackers to steal financial information from users. It was discovered after infecting at least 20 banks in the United States. A Tiny Banker outbreak in Turkey in 2012 affected approximately 60,000 systems. Other incidents occurred in the Czech Republic and the United States. Tiny Banker’s source code was released on a malware website in 2014, and since then, new iterations of this malware have continued to emerge, leading to Tiny Banker being named one of its Top 10 Most Wanted malware in 2016.

ILOVEYOU: The Trojan was distributed in the form of a phishing email with the subject “Kindly check the attached love letter coming from me” and an attachment named “ILOVEYOU” that appeared to be a text file. Recipients who opened the branch became infected; the Trojan overwrote files on the machine before sending itself to their entire contact list. The virus spread to millions of computers due to this simple but effective method of propagation.

Stuxnet: It was a specialized Windows Trojan that was designed to target Industrial Control Systems (ICS). The discovery of Stuxnet, a 500-kilobyte computer worm that infected the software of at least 14 industrial sites in Iran, including a uranium-enrichment plant, heightened awareness of such threats in June 2010. It is said to have been used to attack Iran’s nuclear facilities.

Is Trojan horse a virus or malware?

According to most definitions, the term “trojan virus” is technically incorrect; Trojans are not viruses. A virus spreads by attaching itself to other software, whereas a trojan spreads by masquerading as helpful software or content. Many experts consider spyware programs a type of Trojan because they track user activity and send logs or data back to the attacker.

Whether you call it Trojan malware or a Trojan virus, it’s essential to understand how this intruder operates and what you can do to keep your devices safe.

How does the Trojan horse work?

Let’s try to understand the working of a Trojan horse through an example to understand it in a better way.

You may believe you have received an email from a friend and click on what appears to be a legitimate attachment. A cybercriminal sent the email and the file that you downloaded and opened — installed a Trojan on your device.

The Trojan can spread to other files on your computer when you run the program and cause damage. You may be unaware that anything unusual has occurred because your computer may continue to function normally without indication that it has been infected.

The malware will remain undetected until you perform a specific action, such as visiting a particular website or using online banking. The malicious code will activate once you do any of such activities, and the Trojan will carry out the hacker’s desired action. After the desired action (destroy, change, transmit) has been performed, the malware may delete itself, go dormant, or remain active on your device, depending on the type of Trojan and its creation.


What are the most common types of Trojan horses?

Some of the most common types of Trojan horses are:

Backdoor Trojan: A backdoor Trojan. A Trojan allows an attacker to gain remote access to a computer and control it through a backdoor. This gives the malicious actor complete control over the device, allowing them to delete files, reboot the computer, steal data, or upload malware. A back entrance

Banker Trojan: This Trojan targets users’ banking accounts and financial information.

Game-thief Trojan: This Trojan steals user information from people playing online games.

Distributed denial-of-service attacks (DDoS) Trojan: These programs carry out attacks that cause a network to become overburdened with traffic.

Must Explore- What is a Denial-of-Service (DoS) Attack?

Rootkit Trojan: It is a type of malware that hides on a user’s computer. Its goal is to prevent malicious programs from being detected. Thus, allowing malware to remain active on an infected computer for a longer period.

SMS Trojan: Itis a type of short message service (SMS) Trojan. The Trojan infects mobile devices and has the ability to send and intercept text messages.

Mailfinder Trojan: This Trojan harvests and steals email addresses that a user stores on his/her computer.

Infostealer Trojan: This Trojan installs Trojans or prevents users from detecting the presence of a malicious program.

Downloader Trojan: This Trojan targets an infected computer with malware and then downloads and installs additional malicious programs.

Fake antivirus Trojan: This Trojan masquerades as antivirus, and it also detects and removes threats in the same way that a regular antivirus program does.

Instant messaging Trojan: This Trojan steals users’ logins and passwords from IM services.

Trojan Exploit: This Trojan contains code or data that uses specific vulnerabilities to take advantage of an application or system.

Trojan-Spy: This program monitors how you use your computer, for example, by tracking the data you type into your keyboard or taking screenshots

How to recognize a Trojan horse?

A Trojan horse virus can stay on a device for days or weeks without the user realizing it. Even so, early symptoms of the presence of a Trojan include sudden changes in computer settings, a decrease in computer performance, or unusual activity. The most effective way to detect a Trojan is to search the device with a Trojan scanner or malware-removal software.

What are the different ways to remove a Trojan from your device?

Once a Trojan has infected your device, the universal way to clean it up and restore it to its original state is to run a full system scan with a high-quality, automated anti-malware tool. Some of the tools to remove a Trojan are:

  • MalwareFox
  • Spybot – Search & Destroy
  • SUPERAntiSpyware 
  • Malwarebytes
  • Emsisoft Emergency Kit

Many free antivirus and anti-malware programs detect and remove adware and malware. Many anti-malware programs prevent further infection by cutting off communication between the inserted malware and any backend server, isolating the Trojan.

How to protect against Trojans?

Because Trojans rely on tricking users into allowing them to enter the computer, you can avoid most infections by remaining vigilant and practicing good security habits. Maintain a healthy skepticism toward websites that offer free movies or gambling, preferring to download free software directly from the producer’s website rather than from unauthorized mirror servers.

Other good practices include:

  • Using long passwords
  • Using a firewall to protect your system
  • Conducting routine diagnostic scans
  • Avoiding untrustworthy or suspicious websites
  • Being wary of unverified attachments and links in unknown emails
  • Keeping your applications up to date and ensuring that any security flaws are patched
  • Configuring automatic updates for your operating system software to ensure you have the most recent security updates

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What distinguishes the Trojan Horse?

Trojan horses, unlike viruses, do not replicate themselves, but they can be just as destructive.

Can antivirus software detect Trojan?

An effective antivirus program searches files for valid trust and app behavior, as well as trojan signatures, in order to detect, isolate, and remove them as soon as possible.

Is Trojan considered malware?

A Trojan Horse is a form of malware that infiltrates a computer by pretending to be a legitimate program.

What distinguishes worms from Trojan horses?

A worm replicates itself and spreads to other computers via a network. A Trojan Horse is a type of malware that steals sensitive information from a computer system or a computer network. Worms' primary goal is to consume system resources.

About the Author
Anshuman Singh
Senior Executive - Content

Anshuman Singh is an accomplished content writer with over three years of experience specializing in cybersecurity, cloud computing, networking, and software testing. Known for his clear, concise, and informative wr... Read Full Bio