Let’s get this out of the way: a Trojan horse is a type of malware; it’s not a virus. A computer virus is a program that’s designed to corrupt data. It injects its own code into other files, potentially turning them into agents of digital chaos. But a Trojan is far more sophisticated.
People say Trojan horse virus instead of Trojan horse malware because the word virus has falsely become a catch-all term for all types of malware, such as worms, adware, spyware, Trojans, etc.
What does a Trojan do?
Have you heard of the Greek mythology story about the Trojan horse? The Greeks hid soldiers inside a giant wooden horse and left it as a gift to the people of Troy. The people of Troy opened the gates and took the Trojan in as a gift. Once behind the city walls, soldiers helped their army pillage Troy.
Trojan horse malware works similarly. It can be a piece of software on a USB drive, website, or email attachment that appears friendly and functional but is quite malicious. Once a Trojan enters a system, it can perform various malicious tasks, depending on its capabilities. Here are some Trojans and what they do:
- A backdoor Trojan gives a threat actor complete access and control of your system or network.
- A banker Trojan helps a hacker steal your banking, debit card, or credit card data.
- A game thief Trojan steals sensitive information related to gaming accounts.
- SMS Trojans can spy on you by intercepting your texts.
- A ransomware Trojan encrypts your data and demands a fee to restore access to your files.
- Mailfinder Trojans share your list of contacts and their email addresses with cybercriminals.
- Botnet Trojans make your computer a part of a malicious botnet in order to attack other devices.
- Clicker Trojans help hackers defraud advertisers by artificially raising traffic volumes.
Signs of a Trojan horse infection
Even if a Trojan only uses your computer to attack others instead of attacking you directly, it can slow down your system or network. In addition, a Trojan may throw up popups on your screen. You may also notice changes to your files or folders or mysterious new programs on your computer.
If a data-stealing Trojan hits your computer, then you may notice strange activity on your credit card or bank account. You may also notice alarming activity on your credit report. Your friends or family may mention receiving strange messages from you.
How to defend yourself against Trojans
The first step towards defending yourself against Trojans is to arm your computer with anti-malware technology. Whether you use Windows or macOS, your system probably can’t block all Trojans with its default security software. Look for anti-malware software that can crush all types of malware, from viruses and worms to ransomware, spyware, and Trojans.
You should also regularly check for security updates for your software because many Trojans exploit system vulnerabilities. In addition, keep your firewall active to protect your network from Trojan attacks.
While having good security tools is critical, the best way to stop Trojans is to stay vigilant. After all, many Trojans, much like vampires, need permission. Think twice before downloading software from peer-to-peer networks, websites, emails, or instant messages to stay safe from deceptive malware.