What Is a Trojan Horse?

A Trojan horse, also known as a Trojan or Trojan virus, is a type of malware that infiltrates a device by disguising itself as legitimate software or files. Named after the Greek myth, Trojan horses trick users into secretly installing malware on their devices. Once installed, Trojans can grant backdoor access to systems and devices, spy on users and steal sensitive data.

How Does a Trojan Horse Work?

Contrary to its name, Trojan viruses are not viruses, but rather, a type of malware. They cannot replicate themselves like viruses can and need to be downloaded by a user. Cybercriminals often use social engineering tactics to trick people into installing Trojans on their devices. Trojan horses hide in email attachments, links or downloadable software from malicious websites or ads. When a user downloads what appears to be a safe file or software, they have actually installed malware on their device.

How Does a Trojan Horse Work?

Types of Trojan Horses

Here are a few of the many different types of Trojan horses.

Backdoor Trojan

Backdoor Trojan

Backdoor Trojan horses grant cybercriminals remote access to a device. When a backdoor Trojan infects a device, the device becomes a “zombie” – a device controlled by a cybercriminal. This allows cybercriminals to delete files, steal data, change settings, reboot the computer and upload other types of malware.

DDoS Trojan

DDoS Trojan

A Distributed Denial-of-Service (DDoS) attack is an attempt to disrupt the normal traffic of a targeted server. It slows down and crashes servers by overwhelming them with a flood of internet traffic. DDoS Trojans are programmed to carry out DDoS attacks by infecting devices and turning them into “zombie” devices to participate in a botnet – a network of infected computers under the control of a single attacking party. Once the cybercriminal has a large enough botnet, they can carry out a DDoS attack and flood a server with internet traffic to deny service.

Rootkit Trojan

Rootkit Trojan

A rootkit Trojan tries to conceal certain objects and activities on an injected device. The main goal of rootkit Trojans is to gain administrative access to remain undetected by the user and extend the time they can infect the device. With administrative access, this type of Trojan can turn off antivirus software and other security settings to remain undetected and steal as much data as it can.

Ransomware Trojan

Ransomware Trojan

Ransomware Trojans deliver ransomware to a user’s device to lock them out of their files or the device itself. Ransomware is a type of malware that encrypts a victim's files or devices and prevents the victim from accessing them. The cybercriminal promises to return access to the encrypted files or devices after the victim has paid a ransom; however, there’s no guarantee that a victim will regain access to their files or devices if they pay the specified ransom.

How To Detect a Trojan Horse

It can be difficult to find a Trojan horse that has infected your device. Since Trojan horses look like harmless files, they can go undetected without the use of high-end antivirus software. However, if you notice unusual behavior on your device, then a Trojan horse might have infected it. Here are some of the signs to look out for:

  • Slow performance
  • Random pop-up ads
  • Frequent crashes
  • Missing or altered files
  • Newly installed applications
  • Changed system settings
How To Detect a Trojan Horse

How To Prevent Trojan Horses

Avoid suspicious attachments

Cybercriminals will send you phishing emails to download an attachment with hidden malware. If you received an unsolicited message with a suspicious attachment, you should avoid downloading the attachment to prevent Trojan horses from infecting your device. Scan the attachment with antivirus software before clicking on it to check if it has any hidden malware.

Use antivirus software

Antivirus software is a program that detects, prevents and removes known malware from your device. Investing in high-end antivirus software will help detect and remove any hidden Trojan horses installed on your device. Antivirus software will also detect and prevent incoming Trojan horses before they can infect your device.

Only download software from reliable sources

Avoid downloading software from torrent websites, malicious advertisements and other unreliable sources. These sources often try to get you to download software that has hidden malware. Only download software and applications from reliable sources such as Apple’s App Store and the Google Play Store to prevent Trojan horses from infecting your devices.

Keep your software up to date

Some cybercriminals try to exploit the security vulnerabilities in software, an application or device to install Trojans. You should always keep your software up to date to patch any security vulnerabilities and add new security features that'll better protect your device from Trojan horses.

Store your information in a password manager

A password manager is a tool that securely stores and manages your personal information in an encrypted digital vault. With a password manager, you can safely store your login credentials, credit card information, IDs and other sensitive documents. A password manager uses strong encryption to protect your personal information from Trojans and can only be accessed with a master password.

Keep Your Information Safe From Trojan Viruses With Keeper®

You can protect your information from Trojan horses by using antivirus software and storing your personal information in a password manager like Keeper. Keeper Password Manager uses zero-knowledge encryption to protect your sensitive information from unauthorised access.

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