Computer viruses

Computer virus is a program intentionally written by some software developer to cause damage to the computer, programs and files in which it found itself. The computer virus may be designed to display unwanted messages.

The computer virus is a program that has the ability to replicates itself by changing other programs to include a copy of itself. A virus causes the infected computer system to function in ways not originally planned. The computer virus cannot be seen with your natural eyes yet the effects can be notified on an infected system.

Types of Computer Virus

There are basically three ways in which a virus will infect your microcomputer.

Boot sector virus

Executable file virus

Document virus

Boot Sector

A boot sector virus infects hard drives and flash disks by making itself available on the boot sector of the disk. Booting up from an infected flash disk can cause damage to the hard drive.

Executable file virus

They spread the infection by attacking the code to executable files (EXE.COM) in this way; the virus program will be executable before the host program is executed.

Document Virus

A document virus can affect the document by moving from disk partition table to a different sector and replace it with its own code, therefore infecting document as they are accessed.

Examples of Viruses

The following are example of computer virus:

Trojan horse

Sleeper

Logic bomb

Alabama virus

Christmas virus

Worm

Data crime virus

Jerusalem Virus

Barcelona virus

April 1st virus

Sources of Viruses

Virus infection can happen through the following:

Infected diskettes

Hard drive

Infected CD ROMS

Internet download

E-mail

Illegal duplication of software

Bad handling of computer

EVALUATION

What is a computer virus?

List ten (10) of computer viruses you know.

Explain four out of (1) above how it can infect your computer.

List and explain three sources of viruses.

Explain the three ways in which computer virus can infect your compute