Computer viruses have become widespread due to increased internet usage. A virus is a malicious computer program that can spread itself to other files and computers without permission. While some viruses only cause minor issues, others can severely damage systems by deleting files or rendering computers unusable. Viruses are typically spread by opening infected files from the internet or removable media. It is important to use antivirus software, avoid untrusted sources, and not open potentially risky file types in order to prevent virus infections.

2. Introduction
 Computer virus have become today’s
headline news.
 With the increasing use of the internet, it
has become easier for virus to spread.
 Virus show us loopholes in software.
 Most virus are targeted at the MS
Windows OS.

3. What is a Virus ?
 A virus is just a computer program. Like any
other program, it contains instructions that
tell your computer what to do.
 But unlike an application, a virus usually
tells your computer to do something you
don't want it to do, and it can usually spread
itself to other files on your computer -- and
other people's computers.

4.  In some cases, a virus will execute only a
gentle "personality quirk," such as causing
your computer to make seemingly random
bleeps.
 But a virus can be very destructive; it could
format your hard drive, overwrite your hard
drive boot sector, or delete files and render
your machine inoperable.

5. History of Viruses
 As time progressed many other types of viruses
were developed.
 In 1992, four students at Cornell University
created the MBDF virus.
 This virus attacked Apple Macintosh
computers.
 The virus was released in three shareware
programs: Obnoxious Tetris (computer game),
Ten Tile Puzzle (computer game), and Tetris
cycle (Trojan Horse program).
 This virus was benign, but the perpetrators
were severely punished.

6. General virus types
 Boot Sector Virus
 Macro Virus
 Multipartite Virus
 Polymorphic Virus
 Worms
 Trojan horses
 E-mail viruses
 Stealth Virus

7. How They Spread ?
 Early viruses were pieces of code attached to
a common program like a popular game or a
popular word processor.
 A person might download an infected game
from the internet or copy it from a floppy
disk and run it.
 A virus like this is a small piece of code
embedded in a larger, legitimate program.
Any virus is designed to run first when the
legitimate program gets executed.

8.  If one of the infected programs is given to
another person on a floppy disk, or if it is
uploaded to internet, then other programs get
infected.
 This is how the virus spreads.

9. The impact of viruses
 ICSA Labs estimates that the cost of a
virus disaster is between $50,000 and
$500,000
 Average server downtime for a virus
is 14 hours

10. The impact of viruses

11. Examples of risky file types
 The following file types should never be
opened:
 .EXE
 .PIF
 .BAT
 .VBS
 .COM

12. TOP 5 Viruses Reported
14
12
10
8
6
4
2
0
W32/klez/h W32-
Bugbear-A
Percent Reported to
Sophos 2003
W32/ElKern-
C

13. Symptoms of Virus Attack
 Computer no longer boots up.
 Screen sometimes flicker.
 Computer runs slower then usual.
 PC speaker beeps periodically.
 System crashes for no reason.
 Files/directories sometimes disappear.
 Denial of service (dos)….. & Many More.

14. Prevention is the best cure
 Run a secure operating system like
UNIX or Windows NT.
 Install virus protection software.
 Avoid programs from unknown
sources.
 Disable floppy disk booting

15.  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.

16. Protect Yourself from Computer Viruses
 AVIEN & AVI-EWS
 CERT
 STOPzilla
 GFI Mail Security for
Exchange
 Anti Virus eScan 2003
 CIAC
 Cyber notes
 ICSA
 Information Security
Magazine
 NIPC (National
Infrastructure Protection
Ctr)
 SANS Institute
 Virus Bulletin

17. How To Scan?

18. Anti-Virus Is Scanning

19. Finding Out A Virus

20. Top 9 Virus Protectors are...
1) PANDA ANTIVIRUS PLATIINUM v7.0
2) NORTON ANTIVIRUS 2003
3) F-PROT FOR WINDOWS
4) MCAFEE VIRUSSCAN HOME EDITION
7.0
5) NORMAN VIRUS CONTROL
6) PC-CILLIN
7) BIT DEFENDER PROFESSIONAL v6.5
8) NOD 32
9) STOPzilla!