This document discusses computer viruses including their similarities to biological viruses, how they work and spread, types of viruses, virus detection methods, and prevention. It notes that computer viruses can replicate and spread like biological viruses, infecting host systems and slowing them down. The main types discussed are macro, boot sector, worm, Trojan horse, and logic bomb viruses. Virus detection methods covered include signature-based, behavior-based, and heuristic-based detection. Prevention methods recommended are using antivirus software, not sharing drives without passwords, deleting email attachments, backing up files, and using secure operating systems.

2. CONTENTS
INTRODUCTION.
Similarities B/w Biological & Computer Virus.
How Does A Virus Work?
Life Cycle Of Computer Virus.
Functional Diagram of VIRUS.
Types Of VIRUS.
Methods Of Detecting Virus By ANTI-VIRUS.
Prevention.

3. COMPUTER VIRUS:
A computer virus is a program or piece of code that is loaded onto your
computer without your knowledge and run against your wish.
OR
A virus is illegal computer code that can do such things as alter programs or
destroy data. Also, the virus can copy itself onto programs, thereby spreading
its damaging effects.

4. Similarities between biological virus
and computer virus:
Computer virus are called viruses because they share some of the traits of biological
Viruses. A computer virus passed from computer to computer like a biological virus
Passes from person to person
• Need a host for residence.
• Capable of self-replicate.
• Cause damage to host.

5. How Does A VIRUS Spread?
 first the virus is linked to the host object in such a
way that it activates when the host
object is used.
 Second virus looks for other suitable carrier
objects and attaches itself to them.
 With this dependency virus slows down the system.
How does a virus work?

6. The virus waits until user transmits the
infected object to another computer
User transmits an infected object to another
computer
The virus locates and infects suitable objects
on the new computer

7. VIRUS
ANTI-
DETECTIN
ROUTINES
COPY
SEARCH

8. TYPES OF VIRUS
MACRO VIRUS.
BOOT SECTOR VIRUS.
WORMS.
TROJEN HORSES.
LOGIC BOMBS.

9. 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.

10. 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

11. WORMS
A worm is also a destructive program
that fills a computer system with self-
replicating information.
Types of WORMS VIRUS:
MAIL WORM
PURE WORM

12. TROJAN HORSE
Trojan Horse is a destructive
program. It usually pretends as
computer games or application
software. If executed, computer
system will be damaged.

13. LOGICAL BOMBS
A logical bomb is a destructive
program that performs an activity
when a certain action has occurred.

14. OTHERS
Time Bomb
Script Virus
Directory Virus

15. Signature-Based Detection-Compare the
contents of a file to a dictionary of virus.

16. Behavior -Based Detection:
Observe how the program execute in the computer
Rather than looking for signature .
Check the suspicious file and show warnings to the
user.

17. Heuristic -Based Detection:
 Detect and remove all threats.
 Create a generic signature.

18. PREVENTION
 Don't share Drive C: without a password and
without read-only restrictions.
 Use Anti-Virus.
 Delete e-mail file attachments.
 Have multiple backups of important files.
 More secure operating systems
e.g. UNIX

19. ANY
QUESTION

20. THANK YOU