We have all heard the term Trojan Horse, but what exactly is it?  A Trojan Horse is a destructive program that masquerades as a harmless application. Unlike computer viruses, Trojan Horses do not replicate themselves, but they can be just as destructive. One of the most dangerous examples of a Trojan is a program that promises to rid your computer of viruses but instead introduces viruses into your computer.

The Trojan can be tricky. Who hasn’t been online and had an advertisement pop up claiming to be able to rid your computer of some nasty virus?  Or, even more frightening, you receive an email that claims to be alerting you to a new virus that can threaten your computer. The sender promises to quickly eradicate, or protect, your computer from viruses if you simply download their “free”, attached software into your computer. You may be skeptical but the software looks legitimate and the company sounds reputable.  You proceed to take them up on their offer and download the software.  In doing so, you have just potentially exposed yourself to a massive headache and your computer to a laundry list of ailments.

When a Trojan is activated, numerous things can happen.  Some Trojans are more annoying than malicious.  Some of the less annoying Trojans may choose to change your desktop settings or add silly desktop icons.  The more serious Trojans can erase or overwrite data on your computer, corrupt files, spread other malware such as viruses, spy on the user of a computer and secretly report data like browsing habits to other people, log keystrokes to steal information such as passwords and credit card numbers, phish for bank account details (which can be used for criminal activities), and even install a backdoor into your computer system so that they can come and go as they please.

To increase your odds of not encountering a Trojan, follow these guidelines.  

1. Remain diligent
Trojans can infect your computer through rogue websites, instant messaging, and emails with attachments.  Do not download anything into your computer unless you are 100 percent sure of its sender or source.

2.  Ensure that your operating system is always up-to-date.
If you are running a Microsoft Windows operating system, this is essential.

3. Install reliable anti-virus software.
It is also important that you download any updates frequently to catch all new Trojan Horses, viruses, and worms.  Be sure that the anti-virus program that you choose can also scan e-mails and files downloaded through the internet.

4. Consider installing a firewall.
A firewall is a system that prevents unauthorized use and access to your computer.  A firewall is not going to eliminate your computer virus problems, but when used in conjunction with regular operating system updates and reliable anti-virus software, it can provide additional security and protection for your computer.

Nothing can guarantee the security of your computer 100 percent. However, you can continue to improve your computer security and decrease the possibility of infection by consistently following these guidelines.

Antivirus software is used to prevent, detect, and remove malicious software (commonly known as malware) from a computer. Malware includes computer viruses, worms, and trojan horses. The best software may also prevent and remove adware, spyware, and other forms of malware.

A variety of strategies are typically employed within the best antivirus software. Signature-based detection involves searching for known malicious patterns in executable code. However, it is possible for a user to be infected with new malware in which no signature exists yet, typically called zero-day threats.

To counter these zero-day threats, heuristics can be used. One type of heuristic approach, generic signatures, can identify new viruses or variants of existing viruses by looking for known malicious code (or slight variations of such code) in files.

The best antivirus software can also predict what a file will do if opened/run by emulating it in a sandbox (test area) and analyzing what it does to see if it performs any malicious actions. If it does, this could mean the file is malicious and the software will quarantine, delete or take some other precautionary action.

It is generally agreed that if you have a Windows-based operating system without antivirus software installed and are connected to the internet, you will most likely be infected in less than 2 hours. When looked at in this way, securing your computer with the best antivirus software becomes a top priority.

How do you select the best antivirus software for your needs?  You start by asking yourself a series of questions.  Do you need antivirus protection on its own or do you need additional functionality? Do you need a firewall? Do you need file encryption? Do you need control over which websites can be viewed (parental control)? Do you use the computer for gaming? What are your system requirements?  How much do you want to spend?  Will you need technical support?

Once you are able to answer these questions, you can begin to research which product will best meet your needs.  Product reviews, internet forums and user statements provide a great starting point. AV-Comparatives, PC Pro, and Consumer Reports are just a few good sites that offer forums and research on the best software currently available.

There are numerous antivirus software products available on the market.  Take the time to choose the best antivirus software that meets your specific needs.