Trojans | What Are They?
Trojans, also known by the name Trojan Horses, are malicious software applications which appear to be performing a desired action for the user while in reality creating a backdoor entrance to the system for hackers to use hence it takes its name from the famous Trojan horse which was used to defeat Troy in Ancient Greece.
The main purpose for Trojans to be developed is to allow remote access to the system for hackers. The amount of access allowed depends on the Trojan and the system the Trojan is installed on. Hackers can normally attack Trojan-infected computer in many ways:
• Using the computer as part of a bot net (to use as a Zombie to send spam emails and perform Distributed Denial of Service attacks)
• Theft of private information
• Installing software – more typically, other malicious software
• Download and upload of files
• Modification and deletion of files
• Keystroke logging
• Viewing the user’s screen
• Using storage space
A Trojan need not have been developed by a particular hacker in order for that hacker to control it. Any hacker who has a good knowledge about the Trojan and about network connections can scan on a network for Trojans and simply control all the computer that contain them.
Trojans can get installed on user systems in many ways:
• Software downloads – Trojans can be given as part of a file sharing network
• Websites containing executable content – Trojans may be included as an ActiveX control
• Attachments on spam emails
• Application exploitations – if there is an error with a particular application, the Trojan can get installed in its place
• Social Engineering methods are used to convince users that the Trojan is a legitimate program and should be installed to perform some basic function
As soon as you find a Trojan on your computer, you should take measures to remove it. The best way to remove Trojans is to use a web-based system scanning/ cleaning service or to use a legitimate virus guard application which has a good virus database which contains most of the Trojans available today.