When you use different devices, especially electronic and digital products, you should be aware of the risk of them being infected with viruses and malware, as well as your information being leaked. This contamination happens in various ways, such as installing a file infected with Trojans, Trojans, and viruses, clicking on malicious links, or other similar examples.

What is a Trojan?

You may have heard the name of the Trojan horse. The horse that led to the fall of the city of Troy in the ancient Greek story called the Trojan horse. In the world of computers and electronic systems, especially those that have an operating system, the situation is not much different.

In fact, the Trojan is a malware and a virus, it has a legitimate appearance; But by installing malicious programs without permission, it infects your system.

You may not have noticed the installation of this malware at first glance, but after a while you will feel that many things are not normal! Trojan viruses not only steal your personal information, but can also commit computer crimes and criminal activities with your identity.

The important thing is that Trojans are usually installed in the form of legitimate and tempting programs and games to help you and take control of your system. Their easiest job is to delete your files and disable the system.

How does the Trojan work?

So far, you are familiar with the definition of Trojan virus; In this part, we want to see how Trojan infects systems and extorts money from them.

The important thing to know is that a Trojan is an installation file. So the user mistakenly downloads and installs the infected program and then his system suffers.

The next important point is that Trojans do not multiply like viruses and are only installed on your device in the form of an installer with files in exe or apk format.

However, the most common way to install Trojans is through email and its attachments. Trojan developers usually use spam methods to send their emails. As soon as the email is opened and the attached file is downloaded, the Trojan server is installed and this malware starts working every time the system is turned on.

In addition, a system infected with Trojan malware can transmit it to other systems. Hackers take control of your system remotely and infect other systems by creating a network called botnet.

Some Trojans install additional malware on your system and then bypass your security settings. While others try to disable your antivirus.

What does a Trojan look like?

A Trojan is usually installed as a software or program on a computer or mobile phone, and usually you cannot remove it without the help of a Trojan Remover.

Get to know the types of Trojan viruses

Now it’s time to fully understand the types of Trojans and know what destructive effects each one has on your system.

Backdoor Trojan

This type of Trojan allows attackers to remotely control the infected computer. Based on this, the hacker can perform tasks such as sending, receiving, launching and deleting files, displaying information and restarting the system.

Backdoor Trojans are commonly used to create a botnet or zombie network that can lead to cybercrime.

Exploit Trojan

This malware contains data or code that exploits vulnerabilities in your system’s application software to infect it.

Banker Trojan

As the name suggests, banking Trojan malware is designed to steal your account information for online banking systems, electronic payment systems, and credit cards.

Clampi Trojan

Clampi, also known as Ligats and Ilomo, wait for a user to log in to perform a financial transaction, such as accessing online banking or entering credit card information to make an online purchase.

Clampi is so sophisticated that it hides behind firewalls and remains undetected for a long time!

Cryxos Trojan

Cryxos is commonly known as scareware or fake support requests. Typically, victims receive a pop-up message that says “Your device has been hacked” or “Your computer is infected.” The user is directed to a phone number for support. If the user calls this number because he is under pressure, he will pay the fee.

In some cases, the user may be asked to provide his device remotely to a so-called expert. In this case, you should definitely wait for your information to be stolen.

DDoS Trojan

This malware performs DDoS (Distributed Denial of Service) attacks against the target address. By sending several requests – from your system or several other infected systems – the attack on web addresses starts.

Downloader Trojan

Downloader Trojans, or downloader trojans, can download and install new versions of malicious programs, including older trojans and adware, onto your computer.

Trojan Dropper

It is interesting to know that hackers install this type of Trojan on your system so that you do not notice the installation of malware. Usually, antiviruses are not able to scan all the components inside this type of Trojan.

Fake AV Trojan (FakeAV)

This type of Trojan has an interesting function. FakeAV malware simulates antivirus functionality. Accordingly, in exchange for identifying and removing threats, even unreal ones, they extort money from you.

Game Thief Trojan

This type of Trojan steals account information from online gamers.

Trojan Geost

Geost is an Android banking Trojan. This malware hides in malicious programs that are randomly distributed through unofficial web pages with server hostnames. Victims usually use this pseudo-malware when they are looking for apps that are not available on Google Play.

After downloading and installing the application, the desired program requests permissions that, if enabled, allow malware to be infected.

Instant Messenger Trojan

These malwares steal your login information to applications such as WhatsApp, Facebook Messenger, etc. This type of Trojan allows the hacker to control chat sessions and send the Trojan to anyone in your contact list. They can also perform DDoS attacks using your computer.

Mailfinder Trojan

This Trojan can collect email addresses from your system and allow criminals to send mass messages of malware and spam to your contacts.

Ransom Trojan

This trojan changes your system information so that boiler does not work properly, or you can no longer use certain data. Hackers will restore your device’s functionality or freeze your data only after you pay the ransom they demand.

Remote Access Trojans

Remote access Trojans help hackers gain complete control over your system. These malware can be used to steal information or spy. Once the host system is compromised, the hacker uses this system to infiltrate other devices and create a botnet.

Rootkit Trojan

Rootkits are designed to hide certain activities on your system. Usually, their main purpose is to prevent malicious programs from being detected.

SMS Trojan

This malware can charge you by sending text messages from your mobile device to other phone numbers.

Spy Trojan

This type of Trojan can spy on how the system is used. For example, it can steal information by tracking the data you enter through the keyboard, taking screenshots, or getting a list of running programs.

Qakbot Trojan

Qakbot is an advanced banking Trojan. It is said to be the first malware specifically designed to collect banking information.

Trojan Wacatac

Wacatac is a powerful Trojan that can perform various malicious actions on the target system. It usually penetrates the target system through phishing emails, file sharing in infected networks, and software patches.

The purpose of this malware is to steal confidential information and share it with hackers. It can also allow remote access to hackers.

Other examples of Trojans include:

• Trojan-ArcBomb
• Trojan-Clicker
• Trojan-Notifier
• Trojan-Proxy
• Trojan-PSW

What are the symptoms of a Trojan infected system?

Trojans can look like almost anything, from free software and music to in-browser ads and legitimate-looking programs. Your smallest mistake can lead to installing a Trojan and infecting your system.

In the following, we examine the signs of a system infected with Trojans:

• poor performance of the device; For example, slow or frequent system crashes such as frequent Windows blue screen of death.
• change desktop status; For example, the screen resolution may have changed or the colors may look different.
• Changing the taskbar (Taskbar) or its disappearance.
• Show unknown programs in the taskbar that you have not installed.
• Increase pop-up windows; Not just ads, but browser windows that display antivirus products or scans. Be aware that clicking on them will immediately download malware onto your device.
• Redirected to anonymous websites while browsing online.
• Increase in spam emails.

Ways of Trojan virus transmission!

If you’re looking for signs you can spot a Trojan malware, keep the following in mind and see if you’ve used them recently!

Some programs are cracked

Downloading cracked programs with promises of a free version can be tempting. But the cracked software disguises the possible activation key as a Trojan.

Download free programs

Download unknown apps for free What looks like a free game or screensaver can be a Trojan. Especially if you found it from an untrusted site.

Opening infected emails

Opening an infected email attachment. You get a strange email with what looks like an important attachment like an invoice or delivery receipt, but when you click on it, a Trojan is launched.

Visit fake sites

Visiting websites like some popular sites that allow hackers to infect your system in just a moment. Of course, some people use tricks like playing popular movies. But they say you have to install a special player, which is a Trojan.

Are mobile phones also infected with Trojans?

We have to say yes very easily! Trojans and malware are not just for computer systems. Trojans penetrate mobile phones, especially Android models, through infected, invalid and fake applications. In this case, the Trojan pretends to be a legitimate program, although it is actually a fake version of the program full of malware.

Such trojans usually exist in illegal and unreliable app markets and infect the device with ads or through the keyboard.

It is interesting to know that browser extensions can also act as Trojans. Android users have been victims of all kinds of Trojans even from Google Play!

So, be careful that our phones are not safe from Android Trojans, and to prevent them from being infected, we must be careful about the programs we download and the links we open.

What terrible things can be done by Trojans?

Never be fooled by the innocent appearance of any program or link! Because sometimes destructive actions come from them. In the following, we review some of these measures.

espionage

Some Trojans are written with the sole purpose of spying on computers or mobile phones. These spywares wait for the right opportunity to open a specific user account (such as email, server account, etc.), or make a payment on a site, to steal your sensitive information.

These actions are the background for subsequent attacks, such as hacking the site or server and emptying your bank account.

Turning the computer into a zombie and creating a botnet

At the beginning of the article, we said that some Trojans take control of many victim systems and make them zombies, so to speak. These zombies together form a network called Botnet and are used to create various attacks.

One of the attacks carried out by the zombie network is the DDoS attack.

SMS fraud

• Another method of extorting Trojans is sending SMS from your line. This is done with 2 goals:
• An SMS containing a fraudulent link will be sent from your SIM card to extort money from others (this way no one will find the main culprit).
• SMS will be sent to numbers that deduct money from your account in exchange for receiving SMS
• Back up important files to another location where you can restore your files after they are infected with the Trojan and cleaned.
• Protecting all personal information with antivirus and firewall and running periodic scans.
• Avoid opening suspicious and insecure websites.
• Download and install valid programs from legal and reliable sources.
• Do not click on pop-up and tempting ads

Now the question is, if our system is infected with Trojan, what should we do to clean it? Come to the next section to find the answer to this question.

Ways to remove Trojans from computers and mobile phones

The first thing you should do is to immediately disconnect the system from the Internet if you detect a Trojan. Scan the system with a strong antivirus and delete the infected files. The original version of today’s antiviruses are very strong and can detect all types of Trojans.

After identifying the infected files, the System Restore function should be disabled. If this function is not disabled, all deleted malicious files will be recovered and infect the computer again.

In the next step, you must reset the system and enter Safe Mode by pressing the F8 key. Then you can delete the infected programs through Add/Remove programs in the control panel. To ensure that all programs associated with the Trojan are removed, all program files must be removed from the system.

Finally, restart the system.

Conclusion

Trojan is known as English knife; Because it infects your system in different forms and functions. This malware can have a simple function and at the same time have destructive and complex effects. It is a Trojan horse. In this article, we talked in detail about Trojan, its types, removal methods and how to identify a system infected with this malware. If you have any questions or experience dealing with Trojans, we’d be happy to discuss them in the comments section.