Page 68 - Plus_V2.2_C6_Flipbook
P. 68

We have learnt about different types of malware. The damage caused by a virus is unexpected; it can
                  corrupt the system software or destroy data. So this explains what a computer virus does and how it
                  affects your device. Now let us learn about computer viruses in greater detail which will help us to stay
                  cautious and prepared in case of a virus attack!


                       Harms Caused by Computer Viruses

                  Different viruses will affect your computer in different ways.
                     They can crash your hard disk.
                     They can destroy all or some of your data.
                     They decrease the processing speed of the computer.

                     They can reduce or block the memory of the computer or hard disk.
                     They stop you from restarting your computer or keep on restarting your computer.
                     They send e-mails from your account without your knowledge.


                       Types of Computer Virus

                  There are various types of computer viruses that infect the computer in different ways. The most
                  commonly known categories of computer viruses are:
                     Program File Virus
                     Boot Sector Virus
                     Macro Virus
                     E-mail Virus

                  Let us learn about these in detail.

                  Program File Virus

                  A program file virus, also known as file-infecting virus is a type of computer virus that infects executable
                  files (program files such as .exe, .com, .sys, etc.) to make them unusable or damage permanently.
                  When an infected program file is executed, the code of the virus is also executed.
                  Once a virus has been executed, it remains active in the memory of the computer and can infect more
                  programs. Sometime, a program file virus is called file injector. The most commonly known program
                  file viruses are Jerusalem and Cascade.


                  Boot Sector Virus
                  A Boot sector virus is one of the most hostile types of computer viruses that infects the boot sector
                  or the Master Boot Record (MBR) of hard disks or floppy disks. Once a computer system is infected
                  by a boot sector virus, any disk connected to the computer will also be infected. The most commonly
                  known boot sector viruses are Michelangelo and Stoned.


                  Macro Virus
                  A  macro virus is a type  of computer  virus that  is primarily  designed  to  infect  a specific  type  of
                  documents such as Word or Excel files. If we open a macro virus infected document, the macro virus
                  gets active into the memory and starts infecting other documents.

                  66    Premium Edition-VI
   63   64   65   66   67   68   69   70   71   72   73