Trojan or the Trojan horse virus is a malicious and highly dangerous computer program that deceives a computer user. It enters a system or network by pretending to be something normal. It gets its name from the wooden Trojan horse that was used in Greece in ancient time to enter the city of Troy and for destroying it.

The Trojan horse malware tricks, cheat, and deceives a user to fall into its trap by some kind of social engineering and other intrusive ways. An example of the former kind of trick is when an email arrives at a computer user stating that he has won a huge monetary amount but he needs to open a file to actually get the money in his bank account.

At other times the user may be tricked into downloading some kind of file or program for extraordinary benefits. A Trojan horse virus may also infect your computer through an MP3, a video, a computer game, or an app that you download or use without checking the credentials of the website.

Types and forms of Trojan attacks

A Trojan virus attack can be mild or may also have a very profound impact. Ransomware uses the Trojan horse virus to encrypt the data files on the hard drive of a personal computer and the attacker then demands Bitcoins or any other cryptocurrency to provide the user the key to decrypt the files again.

A Trojan Horse may also create a backdoor entry for the attacker to access all information that is contained in a computer or even in the cloud through the computer. Hence a Trojan enables a web attacker to get access to business, financial, bank, and other kinds of valuable information as well, which can be used in many illegal ways. The attacker may also threaten to publish sensitive data and content stored on PC at public portals and other areas and demand ransom for his/her silence. Apart from infecting a single computer directly, a Trojan horse may also infect and penetrate other devices that form part of the network including the smartphones and mobile.

Other common harmful actions that are or can be associated with the Trojan horse virus are:

• Send SMS with a high cost
  A Trojan horse may be used by an attacker to send costly SMS messages to another number or many different premium phone numbers.
• Turning your computer into a slave zombie
  An attacker may use a Trojan horse to enslave your computer in a network while not wanting or demanding anything.
• Spying
  A Trojan horse may be used by an attacker just to spy on your activities on the Internet and web, or to extract valuable financial and other kinds of personal data.
• Backdoor entry
  The Trojan horse provides a backdoor entry to other worms as well.
• The DDoS attack
  This Trojan can increase the web traffic to any network exponentially and can fail and abandon it completely.

How to prevent Trojan attacks?
Only your attention and prompt supervision of all activities done on the computer can prevent the Trojan attack. You should always stay away from the questionable websites, dubious links, and harmful and pirated material that are now widely locatable on the web.

One of the best ways to prevent Trojan horse virus attacks is to download and install a potent and good antivirus software on your personal computer, laptop, or smartphone. If you do not want to invest in an antivirus right now you can try a good and reputed antivirus free of cost as well. The antivirus software programs today offer a number of features and have comprehensive web protection capabilities. They will provide you alerts against the phishing websites and spam, and will help you stay away from the dangerous websites, pirated content, harmful links, and emails. Once you have an antivirus installed on your computer, it will provide you valuable information and security advice for all the websites or content you download.

Still, you need to be aware and you should refrain from being trapped into lucrative offers that seem to be out of the world and which are common sources of Trojan horse infection.