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WEEK 3

Topic: COMPUTER VIRUSES

Content:

  • Meaning
  • Types of Computer Virus
  • Examples of Viruses
  • Sources of Viruses

Sub-Topic 1: – Meaning and Types of Computer Viruses

(a)       Meaning        

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 message

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 way not originally planned. The computer virus cannot be seen with your natural eyes yet the effects can be notified on an infected system.

(b) Types of Computer Virus

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

  1. Boot sector
  2. Executable file virus
  3. Document

BOOT SECTOR:      Boot sector infect 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: 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.

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Sub-Topic 2:

(c)       Examples of Viruses

The following are example of computer virus:

  1. Trojan horse
  2. Sleeper

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