The Anatomy of a Trojan Horse Attack: How It Works and How to Stop It

Blog Reading Time 12 Min Read
February 22, 2023
By: Senesh Wijayarathne

The Anatomy of a Trojan Horse Attack: How It Works and How to Stop It

The Origin Story of the “Trojan Horse”

Trojan Horse Malware can come in different manners with different forms of viruses. The name ‘Trojan Horse’ is associated with the well-known legend of Troy. When we hear the term ‘Trojan Horse,’ our mind takes us back to the Trojan War, as per the legend that says it was fought in the 12th/13th century BCE. Let us go back in time; the Trojan War, which was said to be fought between the Greeks and the city of Troy, where the Greeks used a built giant wooden horse that could fit a small number of soldiers in it to enter the city of Troy by presenting the wooden horse as a gift to the city of Troy. The city of Troy did not know what they were taking into their premises, and the first chance the Greeks inside the wooden horse got, they took advantage and attacked the city of Troy from the inside.

This article about Trojan Horse Malware will give the reader a clear understanding of what Trojan Horse Malware is, how the name “Trojan Horse” comes for this Malware, how it works, types of Trojan Horse Malware, past attacks, and how to recognize and prevent such attacks.

What is Trojan Horse Malware?

How does the term “Trojan Horse” is appropriate for a cyberattack? Well, the answer to that question lies ahead. 

A type of malware that impersonates a legitimate program/application that can be downloaded to a computer or a mobile device is known as Trojan Horse Malware. Social Engineering mechanisms are the essential delivery methods used to hide the malicious code within an impersonated legitimate program/application. Executing that program/application from the victims’ end would enable the attacker to gain system-level access to the users’ device.  

A malware type that is sent to the user’s device via an attachment on an email or a hidden code within an impersonated program/application with a free-to-download file would be the simple answer to the question “What is Trojan Malware?“. The execution of the malicious code with the task that the attacker has designed would start when the attachment or program/application is downloaded to the user’s device. 

The malicious code could be designed to steal sensitive data, achieve backdoor access to management systems, espionage on users’ online activity, gain a system-level reverse shell, etc., depending on the attacker and the type of attack.

If we compare the origin story of the Trojan Horse and this type of Malware, we can see that various qualities are similar. The following are the similarities;

  • For the attackers, a unique attack strategy was the Trojan Horse. The attackers besieged the city for a decade and could not conquer it. The access they needed was given to them straightway by the Trojan Horse. Similarly, the Trojan Horse Malware can be an excellent way to get behind solid defenses.
  • The appearance of the Trojan Horse was shown as a gift. Similarly, the Trojan Horse Malware displays as an official legitimate software or application that the users require.
  • Greek soldiers who jumped out of the Trojan Horse took control of the city’s defense system from the inside. With the Trojan Horse, a malware program will take control of your computer/mobile device, which may leave it vulnerable to other attacks as well.
  • The greek soldiers could have attacked the city of Troy with different methods after coming out of the wooden horse, same as that the Trojan Horse malware can be designed(coded) to perform various malicious activities.

The Approach by the Horse

For the Trojan Horse Malware to manifest within a system, it would take the user to download the server-side of the software or application for it to work; meaning, for a Trojan attack to execute on a user’s device or system, the implementation of the executable (.exe), the android package (.apk), or the iOS app package (.ipa) should be installed. Moreover, legitimate-looking email attachments, applications, and software are primarily used to spread Trojan Malware among people. Cybercriminals also use social engineering tactics to share and infect devices. Tactics such as banner advertisements, website links, and pop-up advertisements could hold hidden malicious files that would lead to a Trojan Horse Attack.

Any devices that Trojan Horse Malware has already infected could also spread it to other devices. The infected primary device that is being used to spread Malware or Virus can be known as a Zombie Device. With a zombie device, the cyber attacker will gain remote control of the victim’s device without the user knowing about it. Using the zombie device, the cyber attacker could continue to share the Trojan Horse Malware or any other malware or virus across the devices connected to the network; this is known as a botnet.

Common Types of Trojan Horse Malware

Trojan Horse Malware could be used for various purposes, making us vulnerable to many types of Trojan Horse Malware that a cyber attacker could execute. The most common types of Trojans that have been used include:

Backdoor Trojan

Gaining remote access to a device with a Trojan attack and seizing control over it with a backdoor to the device is known as a Backdoor Trojan. The backdoor trojan allows the attacker to delete files, steal data, reboot the device, or upload malware; simply having a backdoor to a device would give you almost complete access to the device itself. A botnet is frequently used to create a backdoor trojan through a zombie device of a network.

Exploit Trojan 

When a Trojan Malware contains data or code that takes advantage of unique vulnerabilities within an application or device system, it is known as an Exploit Trojan. The victim would be targeted using methods like phishing attacks by the cyber attacker using the code or data contained within the malware to exploit a known vulnerability.

Ransom Trojan

Block data on the device or impair its performance so the user can no longer access or use it. This is the purpose of a ransom trojan. The attacker would demand a ransom for the release of the data or unlock the affected data of the device. The attacker will hold the victim’s data until the user or the organization pays the demanded ransom amount.

Spy Trojan

This Trojan Malware is designed to sit on the victim’s device and spy on their day-to-day activity. Spying on the victim’s keyboard actions, accessing the applications and software they use, taking screenshots, and tracking login data of the victim are the applications of this Trojan Malware.  

Banker Trojan

A specially designed trojan to target the victim’s financial information and banking accounts is known as a Banker Trojan. This Trojan Malware aims to steal account data for online banking systems, debit and credit cards, and e-payment systems.

Learn the History So You Can be Protected in the Future – Past Trojan Horse Malware Attacks

Trojan Horse Malware attacks were held responsible for significant damage caused on mobile and computer devices when they were infected to steal user data and information. From the beginning of Trojan Horse Malware, attacks have evolved with the new technology and caused more significant damage. Some of the well-known examples of Trojan Horse Malware attacks include:

Tiny Banker – The Tiny Banker Trojan Malware enabled hackers to steal users’ financial details, leaving them vulnerable to online banking. This Trojan Malware was discovered after it infected more than 20 Banking Institutions in the United States.

Rakhni Trojan – Since 2013, this malware has been around. However, it was used to deliver crypto jacks (which allow the cyber attacker to use the victim’s device to mine cryptocurrency) or ransomware in the recent past. The 2018 Internet Security Threat Report indicated that coin mining in the last months of 2017 was immense, and coin mining activities have increased by 34,000 percent over the year.

Zeus or Zbot – This is another old Trojan Malware that targeted banking customers. This Trojan Malware’s source code was first released back in 2011. It records the victim’s keystrokes as the victim logs into their bank account.

Wirenet – This Trojan Malware is a password-stealing trojan, but this is notable among Linux and OSX users since this was among the first to target those users. Many of the targeted users migrated from Windows operating systems to Linux and OSX operating systems based on perceived security vulnerabilities.

Closing The Stable Before The Horse Bolts! Recognize & Prevent Trojan Horse Attacks

Since Trojan Horse is used as a delivery device for quite a several different types of malware that serve different purposes, you would have to look for many of the same telltale signs if you suspect that Trojan Horse Malware may have breached your device. A few things you should look into include:

  • Poor Device Performance Is your mobile device or computer device crashing more frequently than usual or running slowly?
  • Strange Device Behavior Does your mobile or computer device have unexplained processes being executed or have programs running that you did not initiate?
  • Pop-ups and Spam Interruptions Are you noticing an uptick in the number of interruptions from email spam and browser pop-ups?

If such symptoms are exhibited from your mobile device or the computer device, your device is likely hosting Trojan Malware. Try searching for applications, software, programs, or anything that you did not download or install yourself on your device. You can also enter unrecognized file names into an online search engine to determine whether they are recognized as Trojan Malware.

Guard Your Fortress!

Effective Cyber Security software and applications should be the front line of protecting your mobile device or computer device against the most common cybersecurity threats. An effective internet security solution should have a few main features: speed, frequent scans, and alert reports or notifications as soon as Trojan Malware is detected. A few best practices that you could do in addition to installing verified cyber security software or application to help keep yourself safe from Trojan Horse are;

  • Only download or install software, programs, and applications from sources that you trust completely.
  • Never open email attachments or execute programs sent to you via email from someone you do not know.
  • Be sure to get all software updates or system updates on your devices, and be up to date with the latest patches. 
  • Make sure to download and install a recommended antivirus system and keep it running on your devices.

Keeping Trojan Horses at Bay!

The Trojan Horse Malware has many types that could affect any mobile device or computing device. Since the Trojan Horse Malware could be written with any programming language, the operating system of the mobile device or the operating system of the computer device does not matter.

The Trojan Horse Malware could be used for various attacks depending on the code the attacker has written in the program. If Trojan Horse Malware were running on your device, it would show different symptoms and unusual behaviors. If the user could keep notes of their devices, detecting any Trojan Horse Malware would be possible. Nonetheless, it is safe to take precautions before any disaster, so it would be helpful for users to download Trojan Horse Malware detectors and virus scanners to their devices.