A Trojan is a type of virus but it is different from the other viruses in many ways. First it is a non-self- replicating malware. It performs a task according to the need of the creator of the Trojan and usually it infects your computer through Emails. When we download the Email from the Internet or download any other software from the unauthenticated websites, we face these types of problem.
Trojan horses are designed to allow a hacker to attack on your computer remotely. A hacker can gain access to your computer remotely if Trojan runs on your computer successfully. He can perform any operation on your computer according to his needs.
A hacker could perform the following operations on a targeted computer.
• Data theft (i.e. your credit card information, passwords etc.)
• He can download or upload many files from your computer.
• He can modify your data
• He can delete your computer's data
• He can monitor your keystrokes
• He can waste the storage of your computer
• He can also crash your computer.
Trojan horse is the bridge between the hacker and the user of the computer. They perform the actions according the needs of the hacker. Hackers use some port scanning tools if the infected computer is running in the network then they detect your computer and perform many unauthenticated operations on your computer.
Now we will discuss a few methods through which these Trojan installed and distributed. Sometime when we download software from the file sharing networks, Trojan becomes a part of the software and then becomes installed on your computer. Some other websites that contain the executable contents also affect your computer through ActiveX control. Email attachments are the major causes that affect your computer a lot.
Also, there have been reports of compilers that also have some Trojan horses attached with them. When we compile the code to make an execution, these Trojans are included in the code and it becomes the Trojan after the compilation.
However there is a variety of Antivirus software available on the Internet and they can detect, delete these Trojans and prevent your computer from these Trojans attacks on your computer.
Although it is also possible to remove a Trojan horse manually, it requires the full knowledge about how these particular Trojan horses operate. However, if a Trojan become installed on your computer then it is very difficult to find the targeted area of the Trojan. In critical situations when you feel that your data is unsecured I personally recommend you to remove the whole data from your hard disk and reinstall the operating system. Removing the whole data is necessary because if you only reinstall the operating system, then there is a chance that your computer will become infected again if the Trojan is present in your other local drives.
As botnets are becoming more popular among the hackers, these Trojan are becoming very common too. Bit defender conducted a survey from January to June 2009 and according to this survey these malware are growing at a speed of 83 percent in the world.
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