We explain what a Trojan is and the ways in which this malicious software can be removed. Also, their types and how to protect yourself from them.
What is a Trojan?
A Trojan (or Troy Horse) it is malicious computer software that appears to be a legitimate and safe program, but when a user executes it, it gives the attacker access to the computer remotely. The term is used in computing and refers to the Trojan horse used by the Greeks in Homer’s Odyssey.
This malware (malicious file) allows the attacker to access information on the computer, in most cases, to copy and steal personal data.
A user’s computer can be infected with a Trojan when suspicious email attachments are opened or contents of unknown web pages are executed. Unlike viruses or worms, Trojans are characterized by not being able to replicate themselves automatically.
Purposes of Trojans
Trojans are widely used by virtual criminals or cybercriminals to access confidential data, account theft and, mainly, money theft.
Some of the purposes for which a Trojan is created are:
- Use the computer to send spam.
- Install other malicious programs.
- Take screenshots.
- Observe the keystrokes.
- Extract photos from webcam.
- Erase or damage the hard drive.
- Delete or modify data.
- Steal access data and confidential information and then forward it.
Types of Trojans
There is a wide variety of Trojans that fulfill certain functions or attack different areas of a computer. The most common are:
- Backdoor Trojan. Type of Trojan through which the attacker has access to the computer (it does so by generating a backdoor or backdoor) and remotely execute actions.
- Download Trojan. A type of Trojan that unauthorized downloads of content onto the infected computer, which in many cases is other malicious software.
- Banking Trojan. A type of Trojan that copies and steals user data from banking or online payment sites.
- Trojan info and password stealer. A type of Trojan that copies and steals passwords and user information.
- Distributed service Trojan. A type of Trojan that sends requests to a certain web page from infected computers, in order to saturate it and make it fall.
- Clicker Trojan. A type of Trojan that opens certain websites without the user’s consent to give that page more visits.
- Trojan keylogger. A type of Trojan that records the keystrokes made by the user to copy and steal the information that the user sends through this external device.
How do you know if a computer is infected?
Some of the guidelines that indicate that a computer has a Trojan are:
- The computer restarts or shuts down by itself.
- The system works very slowly.
- The operating system does not start.
- Files on the computer disappear or are modified.
- Windows with advertising and / or pornography are opened.
- Pop-ups with strange messages or constantly appear.
- Programs run by themselves or stop working.
- Websites open suddenly.
- The default search engine of the web browser is altered.
How do you remove a Trojan?
When a computer is infected with a Trojan, the performance of certain computer functions is affected and the user runs the risk of having personal data copied and stolen. For this reason, cleaning your computer from Trojans is essential and can be done by following these steps:
- Download and install an updated antivirus.
- Disconnect the equipment from the internet, whether it is connected via Wi-Fi, with an ADSL modem or a network card.
- Open the internet browser (albeit offline) and clear the cache and cookies. It is important to do this step with each browser that is used.
- Run the antivirus in “safe mode”. From there, the antivirus will perform a scan of the computer. This activity may take several minutes, because the antivirus will check all the files on the computer in search of any malicious ones.
- When the antivirus finishes, the harmful files it detected will be displayed. Here the antivirus will give the option to: delete, quarantine or ignore the files found. You should always choose the delete option.
- The antivirus will then request that the computer be restarted.
- Then the computer must be reconnected to the internet.
How to protect yourself from a Trojan?
It is important to take into account some tips or recommendations to avoid opening Trojan software, for example:
- Do not open files that arrive by email, except those of which the sender is known and known to be safe.
- Do not visit dubious or unknown websites.
- Use caution when downloading files using sharing programs such as P2P (Peer to peer). It is always recommended to scan each file with antivirus before opening or downloading it.
- Frequently update your antivirus as new updates always appear.
- Perform periodic scans with the antivirus.
- Use firewall (firewall), a security device that operates between networks to prevent malicious transmission from one network to another.
- Do not install a program if the manufacturer is unknown.
- Download only original programs to your computer.
- Use different web browsers.
Difference between Trojan and computer virus
The term Trojan is often associated with the idea of a computer virus, but it is important to mention that a Trojan is not a type of virus.
Although in both cases it is malicious software that causes damage to the computer and that enter it without the user’s consent. The main difference is that the virus can replicate itself automaticallywhile the Trojan does not. In addition, viruses enter the computer with the intention of destroying and Trojans seek to steal information or open the door of the computer for other malicious software to enter.
What is a spyware?
Spyware or spyware is a type of application that is installed on a computer, without the consent of the user, in order to collect information and then share it with other people for commercial purposes.
The information that spyware provides is in relation to the URLs visited, purchases made through electronic means, bank or personal account information, among others.
Also, spyware impairs the operation of the equipment, which slows down the connection.
In many cases, the spyware is lodged on the computer through free software installation, or it can also be reached via spam e-mails or fake websites.
There are clues that help detect the presence of spyware on your computer. For instance: information or advertising appears on the computer suddenly, change the toolbar without the user having made the changes, or the main page is automatically modified.