What is a Trojan horse virus? (and what to do if your system gets infected)

If you remember your Greek mythology, you know what a Trojan horse is — but what about the online version? This kind of sneak cyber attack can breach operating systems and cause significant damage. If undetected, they continue running in the background, stealing more and more sensitive information.

Understanding how these viruses work and how to eliminate them is crucial for staying safe and secure online. In this article, we explain what a Trojan horse virus is, common signs of this kind of cyberattack, and how to remove a Trojan horse virus from your system. Let’s go!

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The Trojan horse virus takes its name from Greek mythology. According to the story, a wooden horse was presented to the people of Troy and brought within the city gates — but the hollow horse was actually filled with enemy soldiers. Similarly, a Trojan horse virus deceives users into installing it on their computer system, where it wreaks all kinds of havoc. This type of malware is disguised as legitimate software, but once installed, it steals sensitive information, damages files, or gives the attacker further unauthorized access to their victim’s system. 

Trojan horse viruses are one of the most common types of cybersecurity threats. They can be spread through email attachments, software downloads, or infected websites, and can be difficult to detect and remove. To prevent attacks by Trojan horse viruses and to lessen their impact if you do get attacked, it’s essential to take the proper security measures.

In our security series, we're covering different types of malware and viruses that can compromise the security of your systems and data — and therefore, your bank account. Compared to other types of malware, there are a few characteristics that make Trojan horse viruses unique. 

Overall, Trojan horse viruses use a particular method — similar to scareware — to deceive their victims and infect computer systems. Unlike viruses, which can self-replicate and spread to other systems, Trojan horse viruses rely on users to install them manually. They can even be hidden in legitimate software or files, making them difficult to detect. 

Once installed, Trojan horse viruses get up to all kinds of mischief, although they do have specific goals that are different from other malware, such as worms and ransomware. Worms are self-replicating and can spread quickly through networks, while ransomware is designed to encrypt files and demand payment in exchange for the decryption key. In contrast, a Trojan horse virus is focused on gaining access and then performing specific actions, like stealing sensitive information or giving the attacker remote access to the system.

Trojan horse viruses can have a severe impact on computer systems and cause more than their fair share of harm. Here are some of the ways these viruses can affect your computer:

• Stealing personal information: One of the most common ways Trojan horse viruses can harm your computer is by stealing personal information such as login credentials, credit card numbers, and other sensitive data. The attacker can then use this information for identity theft, financial fraud, or other nefarious purposes.
• Damaging files: Trojan horse viruses can also damage files on your computer by deleting, modifying, or corrupting them. This can lead to data loss, system crashes, and computer performance issues.
• Giving unauthorized access: Trojan horse viruses can give unauthorized access to the attacker, allowing them to control your computer remotely. They can then use your computer to send spam emails or spread malware to other systems.
• Installing other malware: Trojan horse viruses can also install other types of malware on your computer, such as spyware, adware, or ransomware. This can lead to unwanted pop-ups, system slowdowns, or even complete system lockouts.

Not only are Trojan horse viruses sneaky, they can do a lot of damage. It’s vital to protect your computer by using antivirus software, avoiding suspicious downloads and emails, and keeping your software up-to-date. If you suspect that your computer has been infected with a Trojan horse virus, the most important thing is to remove it as quickly as possible and minimize the damage. But first, you’ll need to know the signs of an infection.

• Slow computer performance
• Pop-up ads and unwanted toolbars
• Unusual error messages
• Changes to your homepage or search engine
• Unexplained network activity
• Missing or corrupted files
• Unauthorized access to your accounts or personal information

If you think your system has been attacked by this type of virus, there are a few steps you can take to remove it. Make sure to take action immediately, before the situation gets worse!

Knowing how to remove a Trojan horse virus makes you much better equipped to prevent further damage and future attacks. There are a few main actions you need to take: identify and remove malicious software, clean up infected files, and implement new security measures to prevent future attacks. Let’s go through the process step by step.

• Disconnect from the Internet: First, turn off your Internet connection. This prevents the virus from communicating with its command-and-control server.
• Boot in Safe Mode: Restart your computer and boot it up in Safe Mode. This way, the virus can’t run any processes or services.
• Identify the virus: Use reliable antivirus software to scan your system for malware. Make sure to use reputable, up-to-date software that can catch the latest virus variants. Once the scan is complete, the antivirus software should have identified the Trojan horse virus.
• Remove infected files: Follow the antivirus software’s instructions for removing or quarantining the infected files.
• Clean up your system: Use malware removal software to clean up any remaining traces of the virus. This software will scan your system for any leftover files or registry entries and remove them.
• Restart your computer: Once the cleanup is complete, restart your computer in normal mode.
• Update your software: Make sure to update all your software, including your operating system, web browser, and antivirus software, to prevent future infections.

By taking these steps, you can clear a Trojan horse virus out of your system and stop it from doing any further damage. And if you keep your software up to date, you can reduce the risk of your system being infiltrated in the first place.

At first, Trojan horse viruses might sound like just an annoyance, but they can steal your data or give unauthorized access to attackers — and that can have other nasty consequences for your personal information and even for your finances. So, it’s well worth taking the time to protect yourself!

At N26, we take security seriously. That’s why we’re continually updating our blog with articles on cybersecurity best practices and need-to-know information about the latest scams and attacks. Check out our online security guide for extra tips, and remember to create a strong and secure password.