Do You Have the Germ (Cough! Cough!)

A virus is a program designed to reproduce itself and spread from one computer to another, almost like a human virus that affects other people around you. It can destroy data, display a nasty or silly message, or disrupt computer operations. Sometimes the virus is so bad it can destroy the whole computer operating system, and the hard drive has to be reformatted (completely wiped clean of data) and all of the software reinstalled.

Myth

A lot of people think that their system is immune to viruses, but viruses can develop any number of ways. The truth is, no computer is immune to computer viruses because any time one is vanquished 5 more are written in its place.

How does it work?

Depending on the virus type, it may act a certain number of ways. Most viruses are sent out to destroy or overwhelm your computer. The computer is called the "host", and it then becomes "infected" with a virus.

You can give the computer an innoculation against a virus by using a virus protection program. By using anti-viral software you can disinfect the virus when it appears before damage is done. The ultimate mission of a virus is giving what is called a payload, a small computer program or set of code that attaches to the host computer's programs.

Usually executable files, ones that start the program, and not the data files, ones that hold the information are infected. When the program is run, the computer also runs the virus, which in turn gives the computer the payload. This payload is the set course or final mission of the virus. It attaches to the executable files because the code has to be executed to be spread. That is why very few viruses attach themselves to data files.

The most frequent and worst virus is the boot sector virus. It affects the system files each time you run it.

Symptoms of Viruses:

Displays annoying messages. Your computer starts to play strange sound effects or makes strange noises. You have trouble saving files. Your computer works slower than usual. Files suddenly disappear, or text disappears from the screen. The computer suddenly reboots itself. Most telling sign, your executable files increase in size.

Main Types of Viruses

TROJAN HORSE: This is a computer program that seems to do one thing but actually does something else. It is not a true virus because it does not reproduce itself. A cracker, or cyberpunk, person who thrills at attacking data of others, embeds a hidden program in a file that when executed could reformat your hard drive.

TIME BOMB: This computer program stays in the computer system until a specific date is reached. It is usually carried out by a virus or a Trojan Horse. For example there is a Michelangelo virus that would execute on March 6th if you had the virus and you booted up your computer on that date.

LOGIC BOMB: This is a program that is started by the appearance or disappearance of specific data. It can be carried by a virus or Trojan Horse. It can also be a stand alone program. When the specific data appears, the program is executed. It destroys data on a computer.

WORMS: The program enters the computer system through a network. It can reproduce itself but does not need to be attached to an executabe program to reproduce. Generally it fills up storage space to slow down computer networks.

How to remove the Virus:

• The first way to remove a virus is by deleting it with virus protection software. Be sure and follow the directions of the software, some viruses have to be removed by specific means.

• The second way to remove the virus is to erase the infected program. Usually data files are okay because most viruses do not attach themselves to the data files. Be sure and disinfect all your floppy diskettes and tape backups. These storage devices can reinfect your system with the virus again. If the virus has infected almost everything on the system, it is better to reformat the hard drive and reinstall the programs.

Be sure and investigate the virus first though, because there are some viruses out there that will destroy your complete system unless you follow the correct procedures. Note: Under most state laws creating and spreading a computer virus is against the laws.

Can I "checksum"?

A virus detection program checks the files stored on disk to see if they are infected with a virus, and then disinfects them. It does this by checking the original length of the program against the program each time the computer boots up. Most virsuses attach themselves to the ends of programs, if the program is larger, then a virsus is suspected. This is called CHECKSUM. Checksum is a value that is added by the computer by putting together all the bytes in the file. If the checksum is different, then the virus protection program assumes a virus is present.

Where Do I sign?

Some viruses leave what is called a signature or a set of bytes that is known to exist for a particular virus. It can be identified by the virus software scanning or looking for the signature of the virus. This software scans very quickly. The limitations is that, new types of viruses appear daily and you need to keep updating the software to keep up with it. A good virus protection software will use both checksum and scanning.

For the more advanced user click here to learn how to get rid of viruses that need more attention.

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