Computer Viruses

PRANJAL SAIKIA
KAZIRANGA UNIVERSITY
M.Sc (IT)
Definition of Virus
A computer virus is a program designed to
spread itself by first infecting executable
files or the sys...
Types of Computer Virus
1. Boot Sector Virus
2. Multipartite Virus
4. Worm Virus
5. E-mail Virus
6. Macro Virus
7. Script ...
Boot Sector Virus
A boot sector virus infects boot sector of
computers. During system boot, boot sector
virus is loaded in...
Multipartite Virus
The multipartite virus are the types of
computer viruses that are both a file virus
and a boot sector v...
Worm Virus
A worm virus is also a destructive
program that fills a computer system with
self-replicating information, clog...
E-mail Virus
            An e­mail virus moves around in e­
mail messages, and usually replicates itself 
by automatically...
Macro Virus
A macro virus is associated with application
software like word and excel. When
opening the infected document,...
Script Virus
Commonly found script viruses are
written using the Visual Basic Scripting
edition (VBS) and the JavaScript
p...
Trojan Horse

Trojan Horse is a destructive program.
It usually pretends as computer games or
application software. If exe...
How does it spread


Computer viruses spread by attaching
themselves to other computer program files.



When you exchan...
Prevention is the best cure








Run a secure operating system like UNIX or
windows NT.
Install virus protection s...
Thank You
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Computer viruses

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Computer viruses

  1. 1. Computer Viruses PRANJAL SAIKIA KAZIRANGA UNIVERSITY M.Sc (IT)
  2. 2. Definition of Virus A computer virus is a program designed to spread itself by first infecting executable files or the system areas of hard disks and then making copies of itself. Viruses usually operate without the knowledge or desire of the computer user
  3. 3. Types of Computer Virus 1. Boot Sector Virus 2. Multipartite Virus 4. Worm Virus 5. E-mail Virus 6. Macro Virus 7. Script Virus 8. Trojan Horse
  4. 4. Boot Sector Virus A boot sector virus infects boot sector of computers. During system boot, boot sector virus is loaded into main memory and destroys data stored in hard disk
  5. 5. Multipartite Virus The multipartite virus are the types of computer viruses that are both a file virus and a boot sector virus. They enter the computer via various sorts of media and then embed themselves in the system memory. They then go into the hard drive and infect the boot sector. Once installed in the boot sector these types of computer viruses infect executable files and spread themselves in the system.
  6. 6. Worm Virus A worm virus is also a destructive program that fills a computer system with self-replicating information, clogging the system so that its operations are slowed down or stopped
  7. 7. E-mail Virus             An e­mail virus moves around in e­ mail messages, and usually replicates itself  by automatically mailing itself to dozens of  people in the victim’s e­mail address book.
  8. 8. Macro Virus A macro virus is associated with application software like word and excel. When opening the infected document, macro virus is loaded into main memory and destroys the data stored in hard disk
  9. 9. Script Virus Commonly found script viruses are written using the Visual Basic Scripting edition (VBS) and the JavaScript programming languages
  10. 10. Trojan Horse Trojan Horse is a destructive program. It usually pretends as computer games or application software. If executed, computer system will be damaged
  11. 11. How does it spread  Computer viruses spread by attaching themselves to other computer program files.  When you exchange a file or pen drive with a virus the virus spreads from one computer to the another.
  12. 12. Prevention is the best cure      Run a secure operating system like UNIX or windows NT. Install virus protection software. Avoid programs from unknown sources. Macro virus protection is enabled in all Microsoft applications. Never double-click on an attachment that contains an executable that arrives as an e-mail attachment.
  13. 13. Thank You

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