A Guide to Trojan Viruses

The term Trojan comes from Greek Mythology and refers to a gift which was given to the besieged city of Troy, which turned out to be not so nice after all. It is probably the most recognised term in the world of malware and many millions of computer infections have been caused by trojans.

What are trojans?
By definition a trojan is not a virus. This is because trojans do not replicate, and viruses are defined by the fact that they reproduce themselves as part of the process by which they infect a machine. A trojan is a type of malicious software that presents itself as a legitimate program with the ultimate goal of giving a hacker access to a private computer. Trojans do not attempt to insert themselves into other files as viruses do, but are designed to steal information, or harm the computer systems that they inhabit. Typically trojans rely on downloads for installation. This can be via internet applications or through online games.

What will a trojan do to your computer?
Some trojans are relatively "harmless" to your computer system. They might be designed as part of a co-ordinated attack on another system. Others may open up the possibility of access to your computer, but may lie dormant for years. It is more likely that a trojan infection will pose a greater threat to your system and your data. They can be designed to monitor your internet connection and collect sensitive data from your email account and access passwords. Once sensitive information has been collected it will be relayed back to the hacker, or from the source of origin of the program. Unlike other forms of malware trojans are unlikely to have a noticeable effect on your operating system. Many trojans are designed to work undetected.

Why do you need to avoid trojans?
The key reason for avoiding trojans on your system is to protect sensitive information from being stolen and to protect against the loss of data. Although some trojans are relatively innocuous and do not pose much of a threat to your system, there are others that can result in your bank account and credit cards being vulnerable. There are trojans that can render your system completely inoperable and will destroy all of your data. You may be aware of an infection on your system but can see no obvious impediment to how the system is running.


Even if your computer seems to be working normally you should avoid using it until the infection has been removed. There may be a host of activity being carried out via your system that you are unaware of, or the trojan may be waiting for a trigger, like a date, for the malicious activity to begin. One thing is for sure, you do not want a trojan on your computer.

How do you protect your computer against trojans?
There are a few basic rules that you should follow to prevent trojan infection. You should never open email attachments without checking the file first, even if you know who it’s from. Having up to date Anti-virus software is also crucial. When browsing the web do not run or download any file from a website unless it has the correct level of security clearance.

What you need to do if your computer is infected with a trojan?
If your system has been infected by a
trojan the only solution is via antivirus software. This will detect and quarantine the file and allow you to remove it safely from your computer. Make sure that you have the latest version of antivirus software and scan your machine regularly to ensure it is properly protected.