Trojan Horse Virus: What is it and How to Eliminate it [Ultimate Guide]

During the Trojan War, the Greeks pretended to abandon their siege and left a large wooden horse outside Troy. The Trojans believed it was a peace offering and brought it into the city. At night, the Greek soldiers hidden inside the horse emerged, opened the gates, and the Greek army destroyed Troy from within.

Although the story is a myth, the name “Trojan horse virus” fits the virus exceptionally well because Trojan horse viruses are malicious software found inside legitimate software. Just like Trojans, you install them on your server with consent, and then these malicious scripts take over your computer, allowing the perpetrator to control your computer remotely. 

Thus, protecting your computer from such deadly software is essential.

How? You may ask. In this article, we will show you exactly that. What is a Trojan virus and its types, how does it work, how to detect and prevent a Trojan virus. 

Buckle up; this is going to be a long ride!

How Does Trojan Horse Spread

Hackers usually use a variety of ways to inject this virus into your software. The most common one is social engineering attacks. Cyberattackers may use phishing or spear-phishing attacks to trap the victim, sparking an ingenuine sense of urgency and referring to the Trojan-injected software as the solution. Most victims fall for the trick and install the software, unaware of the devastating consequences that can follow. 

Trojan horse virus can also spread through other infected computers. The cyber attacker can hop through interconnected computers after injecting Trojan into any computer into the server. This allows them to alter or intercept sensitive information throughout the server or contaminate the entire server.

Hackers may also leverage the practice of malvertising to inject machines with Trojans. Malvertising refers to running advertising campaigns that lead to malicious websites. These websites are full of Trojans in the form of banners, pop-ups, or other kinds of ads we usually see on a website.

Sometimes, upon landing on such a website, the Trojan-injected software may also download without the user’s consent or any kind of interaction with the website. In such a case, do not open the file, especially if it is an executable (.exe) file.

Types of Trojan Horse Virus

There are different types of Trojan viruses. Some can alter the files on your computer, while others can send your sensitive information to the cyberattacker. In one way or another, all of them have severe consequences. Here are the most common ones:

• Backdoor Trojan — Enters from the back door of the website; hence, it is named backdoor trojan. This Trojan allows attackers to access your computer even when turned off.
• Downloader Trojan — This Trojan enters your device and downloads other Trojan viruses.
• Ransom Trojan — Refers to the trojan horse virus that holds your website hostage until you provide a ‘ransom.’ The ransom can be cash, bitcoins, NFTs, or anything valuable.
• SMS Trojan — This Trojan impacts smartphones, allowing attackers to intercept incoming or outgoing text messages.
• Banker Trojan — The Trojan steals credentials for online banking, e-payment systems, credit or debit card information, etc. Simply put, this type of Trojan steals information that can be used to extract your hard-earned cash.
• Spy Trojan — As the name suggests, it allows perpetrators to ‘spy’ or monitor the victim, allowing them to collect sensitive information from the infected device.
• Remote Access Trojan — Remote access Trojan seems harmless as it does nothing except include a back door for the cyberattacker.
• Info Stealer Trojan — The name explains it. It is usually injected using malvertising—a practice of injection advertisements that lead to unsafe websites. 
• Game-thief Trojan — It is a Trojan that specifically targets gamers by stealing their user account when they indulge in online games. 
• DDoS Trojan — The Trojan works similarly to a DDoS attack by sending overwhelming requests from a group of computers, causing operational interruptions. Learn more about a DDoS attack in our guide: How to Prevent a WordPress DDoS Attack.
• Infostealer Trojan — Works as a defense system for Trojans. This malware makes it challenging for antivirus programs to detect it.
• Anti-virus Trojan — The last one on the list, the anti-virus Trojan works exactly like a legitimate antivirus but points at non-existent issues to extort cash from users.

How to Detect a Trojan Horse Virus

Before you learn how to get rid of the Trojan virus, you must learn how to recognize it. Since the Trojan horse virus wedges into the system’s file, detecting it can be laborious. Here are a few early signs that can help you detect malware and potentially mitigate its impact:

• Abrupt decline in performance — Trojan viruses can disrupt your device’s performance. If you suddenly experience an unexplainable change in performance, that can be a sign of a trojan horse virus.
• Unexplainable activity — If you notice applications or files that you don’t remember downloading, that can be a sign of a Trojan horse attack. In the previous section, we learned about Trojan types that can download other malicious software. 
• Check your background process — Trojans can hide in your system’s file. Check your task manager (or activity monitor for iMac) regularly. For Windows, press CTRL + ALT + Delete, and scroll down to “Background processes,” and attentively monitor what processes are using the RAM.

• For WordPress — To detect trojans and malware in WP sites, you can use dedicated security plugins such as Quttera Web Malware Scanner, SecuPress, or Jetpack Security.

How to Eliminate the Trojan Horse Virus [Step-by-Step]

After pointing it out, now you have to eliminate it. This section will walk you through the process.

Eliminating a Trojan horse virus can be done effectively by following these steps:

Step #1: Disconnect the Internet and Go into Safe Mode

Malware, like the Trojan horse virus, persistently communicates with a remote server operated by the attacker, which allows the hacker to spy on or control another device remotely. Cutting your device off the internet will interrupt communication, removing the hacker’s interference. 

After cutting the hacker off, restart your device and go into safe mode. The process varies based on your device and operating system. It’s usually the F8 key. Safe mode cuts off most trivial processes, allowing only essential processes to operate, which can help you filter out legitimate and malicious processes.

Step #2: Run an Antivirus or Malware Specific Tools

Once in safe mode, run an antivirus scan. Ensure your antivirus is updated because newer updates bring new measures to eliminate threads we were unaware of before. We have already discussed the Trojan virus, which masquerades as an anti-virus. So, it’s imperative to choose one that is reliable.

Sometimes, antiviruses may fall short of extracting stubborn Trojans. Thus, it’s also wise to use dedicated malware-specific tools that can get the job done more efficiently.

Step #3: Clear the Remnants of The Trojan Horse Virus

After clearing everything up, access the task manager again and end the tasks that you think can be malicious. If you see unfamiliar tasks, look them up. If they are illegitimate, clear them up.

Afterward, go to the Control Panel >> Programs, look for all the unfamiliar software, and carefully eliminate them as well. Lastly, run disk cleanup. Search ‘disk cleanup’ in the start menu. It deletes all the redundant files, including the harmful ones.

Step #4: Update Your Software

Once you are Trojan-free, don’t forget to review and update your software. Update your browsers and extensions. Trojans reside in the extensions as well. So, make sure to eliminate each extension that you believe can be malicious. 

For enhanced safety, never download extensions from third-party websites. If any are in your browser, these should be the first ones to go.

After all, also make sure to update your operating system as well. Security patches are crucial in preventing vulnerabilities that Trojans exploit. Check for updates and install them regularly.

This is the safest Trojan virus removal method. Taking these steps should help eliminate the Trojan horse virus. Finally, if the Trojan persists, reformat as the last resort. 

How to Prevent the Trojan Horse Virus in the Future

Trojans can come from various places. Here’s what to do to ensure safety and prevent catching Trojan horse virus in the future:

• Use VPN when accessing a file-sharing site: File-sharing websites or applications like Dropbox, Google Drive, etc., can be infected with the Trojan virus. As we discussed earlier, once injected, hackers can hop to and from interconnected devices. Thus, using a VPN can mask your identity, saving you from potential threads.
• Don’t respond to suspicious emails: Phishing emails are the number one source of Trojans spreading in your devices. Thus, be mindful of attachments before downloading them on your device. Do not install a file from an unknown sender unless you are entirely sure of its authenticity.
• Stay away from unsecured websites: Hackers love unsecured websites because they make it easier to steal sensitive information and inject malicious code into visitors. Thus, if a website doesn’t have a secure connection, move out of it as soon as possible.
• Use VPN when using public WiFi or don’t use them at all: Public WiFi and security don’t go well together. Therefore, if possible, avoid using it. Otherwise, always use a VPN before connecting to a public Wifi. It hides your IP address and protects you from cyber threats.
• Download only from trusted sources: Avoid downloading files from untrusted sources. If the browser is warning you, evaluate your decision and step back if necessary. Remember, you are just one download away from infecting your device with Trojans. 

The Verdict

Don’t be Trojans! Simply put, Trojans routed the giant horse inside their tribe, and everything spiraled out of control. Similarly, downloading resources from unknown sources can cause circumstances similar to theirs.

The only way to prevent the Trojan horse virus is to take calculated steps and be careful of what you do online. Cyberattackers work tirelessly to invent new malware and viruses. With the advancements in cyber crimes, protecting yourself online is becoming more challenging.

Thus, follow the best security cybersecurity practices at all times. Use a reliable VPN—especially when connecting to a public Wifi—and regularly run your devices through antivirus scans. 

Lastly, until you remove the trojan from your website, make sure to keep it private by using the Password Protected plugin.

Frequently Asked Questions