computer virus

COMPUTER VIRUS

BY:Sumangala and Nikhita

What is computer virus???

•A computer virus is a program that can copy itself and can infect the computer without the users knowledge.

What is Computer Virus???

•Viruses may or may not harm your computer. Destructive viruses are created.•Many virus stay active until turn the computer off.

Major characteristics

• A computer virus has 2 major characteristics:

• 1. Ability to replicate itself.

• 2. Attach itself to other computer.

Signs of Computer Virus!!!•Your computer starts running more slowly than it usually does•Your computer keep crashing•Your computer keep crashing and then restarting•Programmes you normally work with suddenly start behaving oddly•You can't access your disk drives

Computer Virus History!!!•Brain. A was computer virus invented in 1986 by Basit and Amjad Farrq alvi•Some of the oldest viruses are Centipede and walker.•Elk Cloner is a boot sector virus and one of the earliest microcomputer viruses. The Elk Cloner virus was developed in 1982 by Rich Skrenta who was only 15 years old.

Walker

What can Virus do ???• It can infect executable

program files.• It can infect disks, by

attaching itself to hard disks.

• It can infect files that are attached to e-mail messages.

What Virus cannot do ???

• I cannot infect files on write – protected discs, such as CD ROMs.

• It cannot infect computer hardware such as monitors and keyboards.

• Only infects software.

Warning signals !!!

• The computer runs slower than before.• Apps take longer to load.• Unusual error messages appear on the

screen.• You notice changes in file size.• Your computer often freezes.• It restarts own its own.

How does a Virus spread ???

• They spread by infected data through pen drives, e- mails,etc.

• They become active when you turn on the computer.

• Different viruses behave in different ways.

TYPES OF COMPUTER VIRUS

PROGRAM,BOOT, AND MACROVIRUSES

Program Virus

• Program virus infect program files, which have extensions like .com,.exe,etc.

• The virus becomes active when the infected file is active.

• Examples : acid rain, Sunday and cascade.

Boot Virus• Boot virus infect the

boot records of hard disk and floppy disc.

• Boot virus are considered

more dangerous than others.• Examples :devil ,

eek , disk killer,etc.

Macro virus• A macro is a set of

commands written by the user to be executed later.

• A macro virus uses the macro language of the program.

• Examples : mellisa, concept ,etc.