Malicious Software: Trojans - What You Need To Know

A Trojan is a program that may appear to be legitimate, but in fact does something malicious-- it's a bit of software code that does something bad to your computer. Trojans are often used to gain backdoor access - that is to say remote, surreptitious access, to a user's system.

Once a Trojan has been installed on a target computer system, a hacker may have access to the computer remotely and perform various operations, limited by user privileges on the target computer system and the design of the Trojan.

Operations that could be performed by a hacker on a target computer system include:

• Use of the machine as part of a botnet (e.g. to perform automated spamming or to distribute Denial-of-service attacks)
• Data theft (e.g. retrieving passwords or credit card information)
• Installation of software, including third-party malware (infected software)
• Downloading or uploading of files on the user's computer
• Modification or deletion of files
• Keystroke logging
• Watching the user's screen
• Crashing the computer
• Anonymizing internet viewing

While antivirus software and security updates can help protect you from Trojans and malicious software, it is ultimately up to you to keep your computer safe from attacks.
Here are some tips to avoid Trojans:

• Check before you download anything for free.
• Avoid opening e-mails from senders you don’t know.
• If you are not too sure of the purpose of a program, do not allow it to run or install.
• Have a good and reputed security system.
• Don't think that Trojans cannot enter just because you have a security system installed. No anti-virus software can guarantee a complete and thorough protection. Be cautious about anything you install or set up in your system.
• Enable a firewall to protect your system and give you extra protection and keep it on at all times.
• Enable a spam filter in your e-mail.
• Make sure you visit only secure sites.
• Beware of hidden file extensions.
• Avoid sharing files/ folders

Article Source: http://www.abcarticledirectory.com and www.wikipedia.com