Page 20 - Computer Class 05

Macro Virus : This type of virus infects files that are created using certain

applications or programs that contain macros. These mini-
programs make it possible to automate series of operations

so that they are performed as a single action, thereby saving
the user from having to carry them out one-by-one. For
example: Relax, Melissa, Bablus, 097MIY2K.

Resident : This is a general term for any virus that inserts itself in a
computer system’s memory. A resident virus can execute

anytime when an operating system loads.

Encrypted : These type of viruses consist of encrypted malicious code

and decrypted module. These viruses use encrypted code
technique which makes antivirus software hardly able to

detect them. The antivirus program usually can detect this
type of virus when they try spread by decrypting themselves.

File Virus : A file virus is the most common kind of virus. These kind of
viruses usually infect .EXE and .COM files which are the

main components of a program or application. A file virus
can insert its own code into a part of the file so that when

the infected program’s file runs, the virus gets executed first.

Polymorphic Virus : A polymorphic virus changes its code each time an
infected file executed. It does this to evade antivirus

programs.

Trojan Horse : Trojan Horse is a destructive program. It usually pretends as
a computer game or application software. If executed,

computer system will be damaged.

Logical Bomb : It performs it’s task when particular action has occurred,

otherwise it is not harmful. The action can be clicking on the
particular file or folder.

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