Virus Worm and Trojans


My wife Anne asked me several months ago to write about the differences between malicious software called Viruses, Worms and Trojans.  So here it is.

Most people will assume a computer virus has infected their computer when a Worm or a Trojan attacks their computer.   All 3 programs can cause bad things to happen to your computer but each one attacks differently.  The best case scenario is not to get one of the things.  The worst case scenario if you got one of these things is that you will have to back up your data, reformat your hard drive, reinstall your operating system, reinstall your programs and restore your data from your backup.

What Is a Virus?

A computer virus is like a human virus. It travels from computer to computer by attaching itself to a file or an email.  A virus has an executable file (.exe extension after the file name) and cannot infect your computer unless you click on the file to run the program.  One of the viruses back in nineties would show fireworks and corrupt some files.   Please remember the only way a computer virus can travel is through human interaction such as sharing an infected file or emails with infected files as an attachents.

What Is a Worm?

A worm is similar to a virus by design but does not need human interaction to spread the infection.  It can travel from computer to computer by using the email system in a computer.  How it does that is by sending itself to everyone that is in your email address book.  Then it attaches itself to everyone in their email address books and sends itself to everyone in their address books.  It is like that old TV shampoo commercial.  Where 1 girl tells 2 girls about the shampoo then the 2 girls each tell 2 other girls.  The next four girls each tell 2 other girls and the cascade begins.  When this happens, your network will bog down, or your computer will become very slow or unresponsive because of the replication of the worm. Companies have shut down their networks because of worms.  Please remember some worms  are designed to allow others to remotely access your computer and take control of it.

What Is a Trojan Horse?

Remember the Trojan war, Paris kidnapped Helen from Greece, married her and they were living in Troy.  The Greeks wanted to get Helen back and they could not penetrate the walls of Troy.  So the Greeks created a large hollow wooden horse and hid in the horse.  The Trojans rolled the horse into the city believing that the Greeks left.  That night while citizens of Troy slept or were in drunken stupor, the Greeks came out of the horse, took over the city and got Helen back.

The Trojan Horse (aka Trojan) is latest of malicious software to attack a PC or a MAC.   It comes from a website, website toolbar installation, a website link in an email, or useful software    A Trojan, at first will appear to be useful software but will actually do damage once installed or run on your computer.   Some Trojans will hide your files and folders or they will continuously try to get you to purchase something or place new icons on your desktop.  Also there are the Trojans that take you to an undesirable website and reset your home page.   Backdoor Trojans are some of the worse Trojans.  They try to create a backdoor on your PC/Mac and gather your personal information.

Tips to Combat Viruses, Worms and Trojan Horses on Your Computer

Keep The Operating System Updated

The first step in protecting your computer from any malicious there is to ensure that your operating system (OS) is up-to-date. This is essential if you are running a Microsoft Windows OS. Secondly, you need to have anti-virus software installed on your system and ensure you download updates frequently to ensure your software has the latest fixes for new viruses, worms, and Trojan horses. Additionally, you want to make sure your anti-virus program has the capability to scan e-mail and files as they are downloaded from the Internet, and you also need to run full disk scans periodically. This will help prevent malicious programs from even reaching your computer.

Use a Firewall

You should also install a firewall. A firewall is a system that prevents unauthorized use and access to your computer. A firewall can be either hardware or software. Hardware firewalls provide a strong degree of protection from most forms of attack coming from the outside world and can be purchased as a stand-alone product or in broadband routers. Unfortunately, when battling viruses, worms and Trojans, a hardware firewall may be less effective than a software firewall, as it could possibly ignore embedded worms in out going e-mails and see this as regular network traffic.   A good software firewall will protect your computer from outside attempts to control or gain access your computer, and usually provides additional protection against the most common Trojan programs or e-mail worms. The downside to software firewalls is that they will only protect the computer they are installed on, not a network.

Common Sense

Please think about where you are searching and what you are clicking on.

Till next time