Everything about Trojan You Need to Know

Trojan Working
Trojan Working

Trojans are malicious programs that are disguised as something else, like free software or videos. They might seem harmless at first, but they can actually do a lot of damage to your computer.

The term “trojan virus” is not accurate; trojans are not viruses. A virus is a program that spreads by attaching itself to other software, while a trojan spreads by pretending to be useful software or content. Many experts consider spyware programs, which track user activity and send logs or data back to the attacker, as a type of trojan.

History of trojan

Trojans have been around since the early days of cyber security threats, with the first one being created in 1975 by a programmer named John Walker. It was called “Animal.” Since then, malware has become progressively more difficult to detect as it has grown in complexity.

In recent history, there have been a number of cases where Trojans have caused damage and financial loss to their unsuspecting targets. One of the most notable examples is Emotet, which was featured in Europol’s 2021 report on organized crime, SOCTA (Serious and Organized Crime Threat Assessment). Emotet became known as a banking Trojan after using email to attack its victims, causing Chilean bank Consorcio to lose approximately $2 million.

How do trojan works

In contrast to a PC infection, a Trojan horse program is not designed to show itself on a specific PC system. It requires the help of a user to download the server-side component of the application in order to be effective. The executable file would already have been installed and executed on the PC system for the Trojan to attack any device.

A Trojan infection is commonly spread through email attachments or links that appear to be legitimate. The malicious content is usually spammed to as many people as possible in order to spread it as far as possible. When the unsuspecting user opens the email, the malware from the attachment or link is downloaded and installed on the victim’s device. The malware will then automatically run every time the device is turned on.

Gadgets may likewise become contaminated by a Trojan infection when social-designing stunts and strategies are embraced. These stunts power clients into downloading this broken application. The pernicious document can be covered up inside standard advertisements, spring-up promotions or site joins. It’s difficult to tell where a Trojan horse infection has been covered up and numerous individuals load them up into their frameworks without suspecting anything. What’s more, once the Trojan is on your gadget, it can do things like taking your own data, Controlling your gadget or even debilitating it so you need to get a new one.

A PC with a Trojan horse infection is able to spread the infection to other devices. The programmer can turn an infected device into a zombie PC, which gives the programmer control over the device without the user’s knowledge. The PC would function normally, and the programmer can use its resources to spread the Trojan horse across an organization or series of PCs.

Types of Trojan

  1. Banker Trojan – A broker Trojan is a malicious program that targets clients’ financial records and data. It is designed to stealing credit and debit card information, e-payment systems, and online banking information.
  2. Backdoor Trojan – A secondary passage Trojan is a type of malware that allows an attacker to gain remote access to a computer and take control of it using a backdoor. This enables the malicious actor to do anything they want on the device, such as deleting files, rebooting the computer, stealing data, or uploading malware. A backdoor Trojan is sometimes used to create a botnet through a network of zombie computers.
  3. Downloader Trojan – A downloader Trojan is a type of malware that focuses on a PC that has already been infected with other malware. Once it’s found a compromised PC, it will then download and install more malicious programs to it. These could be additional Trojans or other types of malware, like adwareTrojan.
  4. Distributed refusal of administration (DDoS) Trojan – These Trojan projects can be really harmful to organizations by over-burdening them with traffic. It works by sending multiple requests from a single computer or a group of computers to overwhelm a target web address and cause a denial of service.
  5. Fake antivirus Trojan – A phony antivirus Trojan is a type of malware that is designed to trick users into thinking it is a legitimate antivirus program. The Trojan will scan your computer and report findings of risks or infections, even if there are none, and then prompt you to pay to have these “threats” removed. Of course, since the Trojan is fake, the risks it reports are also fake – meaning you’ve essentially just paid money to a hacker for nothing.
  6. Exploit Trojan – A malware program is designed to take advantage of weaknesses in an application or computer system. Cybercriminals target users through phishing attacks and then use the code in the program to exploit a known weakness.
  7. Instant informing (IM) Trojan – This type of Trojan virus specifically goes after instant messaging (IM) administrations in order to steal clients’ login information and passwords. The most popular instant messaging platforms that are targeted by this virus are AOL Instant Messenger, ICQ, MSN Messenger, Skype, and Yahoo Pager.
  8. Game-cheat Trojan – A game-hoodlum Trojan is a type of malware that’s designed to steal account information from people who play games online.
  9. Mailfinder Trojan – A email finder Trojan is a type of malware that is designed to steal email addresses that are stored on a computer.
  10. Infostealer Trojan – This malware can be used to introduce Trojans, or prevent the user from detecting the presence of a malicious program. The components of info stealer Trojans can make it difficult for antivirus systems to detect them in scans.
  11. Remote access Trojan – Much like a Trojan horse found in ancient literature, this form of malware gives the attacker full control over the victim’s computer. The cybercriminal maintains access to the device through a remote network connection, which they use to either steal data or spy on the user.
  12. Ransom Trojan – Ransom Trojans are a type of malware that can blocking users from accessing or using their computer. The attacker will then demand a ransom payment in order to fix the damage or release the locked data.
  13. Short message administration (SMS) Trojan – SMS Trojans are a type of malware that can infect your cell phone and allow attackers to send and intercept text messages. This includes sending messages to premium-rate telephone numbers, which increases the charges on your phone bill.
  14. Rootkit Trojan – A rootkit is a malicious software that conceals itself on a victim’s computer. It does this to prevent security programs from detecting it, which allows the malware to remain active on an infected computer for a longer period of time.
  15. SUNBURST – The SUNBURST trojan was delivered through various SolarWinds Orion Platforms. The trojanized versions of a real SolarWinds document named SolarWinds.Orion.Core.BusinessLayer.dll allowed indirect access to the systems it infected. Once on an objective machine, it would stay dormant for a period of fourteen days before retrieving commands that would allow it to move laterally, execute code, perform reconnaissance, reboot, and end system services. Communication would happen over HTTP to predetermined URLs.
  16. Spy Trojan – Spy Trojans are a type of malware that are designed to secretly monitor and collect information from an infected computer. This can include logging keystrokes, taking screenshots, accessing files and applications, and stealing login credentials.
  17. Crysis Trojan – Cryxos is often associated with scareware or fake help call scams. Typically, victims will get a pop-up message that says something like “Your device has been hacked” or “Your computer is infected”. The user is then directed to a phone number for help. If the user calls the number, they are forced to pay for assistance. Sometimes, the user may be asked to give remote access of their machine to the “customer support technician”, which could potentially lead to device seizure and data theft.
  18. Clampi Trojan – Clampi – also known as Lights and Ilomo – lies in wait for customers to login and make a financial transaction, like accessing their internet banking or entering their credit card information for an online purchase. Clampi is sophisticated enough to hide behind firewalls and go undetected for long periods of time.
  19. 19.Wacatac Trojan – Trojan Wacatac is an exceptionally harmful Trojan virus that can cause a lot of damage to your computer system. It usually invades using phishing messages, file sharing over infected networks, and software patches. Its purpose is to steal confidential information and sell it to hackers. It can also allow remote access to hackers so they can carry out dangerous tasks.
  20. Qakbot Trojan – Qakbot is a type of malware that is specifically designed to target and steal financial information. It is considered to be one of the first pieces of malware created for this purpose and is often used in conjunction with other devices.

Example of most dangerous trojan families


Zeus/Zbot is a malware package that operates in a client/server model. deployed instances of the software call back to the Zeus Command & Control (C&C) center. Zeus/Zbot is estimated to have infected over 3.6 million computers in the United States, including machines owned by NASA, Bank of America, and the US Department of Transportation.

Zeus is a virus that infects Windows computers and steals confidential data like credentials, banking details, and other financial information. The stolen data is sent to the Zeus server, where the attackers can access it. Zeus is particularly effective at stealing this type of data, which makes it a dangerous virus.

The primary weakness of the Zeus system is its reliance on a single C&C server, which was quickly targeted by law enforcement agencies. Later versions of Zeus attempted to mitigate this issue by adding a domain generation algorithm (GDA) that would allow Zbots to connect to a list of alternative domain names if the primary Zeus server was unavailable. However, this did not completely solve the problem.

Zeus has many variants:

  • Zeus Gameover
  • SpyEye
  • Ice IX
  • Citadel
  • Carberp
  • Shylock

ILOVEYOU: The ILOVEYOU trojan was released in 2000 and caused $8.7 billion in global losses, making it the world’s most damaging cyberatta2ck at the time.

Cryptolocker: Cryptolocker is a type of ransomware that’s become increasingly common in recent years. It typically distributes itself using infected email attachments. A common message will contain a password-protected ZIP file with the password included in the message. Once the user opens the ZIP and clicks on the attached PDF using the provided password, the trojan is activated. It will then search for files to encrypt on both local and mapped network drives before encrypting them using asymmetric encryption with 1024- or 2048-bit keys. The attackers will then demand a ransom be paid before they release the encrypted files.

Stuxnet: Stuxnet was a specialized Windows Trojan that was specifically designed to attack Industrial Control Systems (ICS). It’s believed that this virus was used in an attempt to attack and damage Iran’s nuclear facilities. The virus caused operator monitors to show that everything appeared to be business as usual, while it actually changed the speed of Iranian centrifuges. This caused the centrifuges to spin too long and too quickly, eventually resulting in the destruction of the equipment.

Trojan infection symptoms

If you’re seeing new applications in your Start-up menu, receiving fake alerts about viruses or downloaded **** videos, or your computer is suddenly rebooting, it could be a sign that your computer has been infected with malware.

How to defend against Trojans

Trojans usually need user permission to run, for example when users click on an email attachment or enable macros in office documents. Therefore, the best defense against Trojans is to educate users to be cautious about what they click or open. Users should verify the sources of the files sent to them or downloaded from the internet. However, in today’s busy world, it is not always possible to be 100% sure of the sources of these files. Therefore, a few additional measures should be taken.

One of the best ways to protect your computer fromTrojans is to keep all your software up-to-date, especially your operating system (OS), antivirusprogram, and web browsers. Cyber criminals often exploit security vulnerabilities in these programs to plantTrojans on victim computers. Another effective measure against Trojans is to use firewalls to secure your internet connections. Firewalls can filter out malicious traffic and prevent Trojans from being delivered to your device.

There are many types of Trojans, so no single method will get rid of all of them. The first step is to clean the temporary folder and locate malicious entries in the registry. You can then delete them manually while in Safe Mode. The best antivirus tools can detect and remove Trojans automatically. Regular antivirus updates are essential to better detection accuracy.

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