Introduction to Computer Virus

1. Introduction to Computer Virus
Imtiaz Ahmed
S10326
Mr. Muhammad Mohsin Hakro
Introduction to Virus
Final Practical Assignment
ISLAMABAD APPLIQUE
Learning Center of Arts & Technology
Trainee:
Code:
Tutor:
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2. What is Virus?
A computer virus is a malware program that, when
executed, replicates by inserting copies of itself
(possibly modified) into other computer programs,
data files, or the boot sector of the hard drive; when this
replication succeeds, the affected areas are then said
to be "infected“
Viruses often perform some type of harmful activity on
infected hosts, such as stealing hard disk space
or CPU time, accessing private information, corrupting
data, displaying political or humorous messages on the
user's screen, spamming their contacts, logging their
keystrokes, or even rendering the computer useless
An inefficient virus kills its host.
A clever virus stays with it.
– James Lovelock

3. What is Virus?
 Computer viruses are small software
programs that are designed to spread from
one computer to another and to interfere with
computer operation.
 A virus might corrupt or delete data on your
computer, use your e-mail program to spread
itself to other computers, or even erase
everything on your hard disk.
 Viruses can be masked as attachments of
funny images, greeting cards, or audio and
video files.

4. What is Virus?
 Viruses are most easily spread by
attachments in e-mail messages or instant
messaging messages. That is why it is
essential that you never open e-mail
attachments unless you know who it's from
and you are expecting it.
 Viruses also spread through downloads on
the Internet. They can be hidden in illicit
software or other files or programs you might
download.

5. Types of Computer Viruses
 Boot Sector Viruses
Target the boot sector/Master Boot Record (MBR) of the
host's hard drive or removable (USB) storage media etc
 Resident Viruses
Remains in RAM when Computer starts
 Non-resident Viruses
When executed, scans the disk for targets, infects them, and then
exits
 Macro
That is written in a macro language, and embedded into these
documents so that when users open the file, the virus code is
executed, and can infect the user's computer

6. Other Types of Computer
Viruses
 Virus Hoaxes chain email to forward
 Trojan Horses misrepresents itself as useful
 Worms which replicates same copies
 Spam unsolicited bulk email, junk mail, or unsolicited
email
 Adware Unwanted Advertisement
 Spyware Gathers information and transmit
 Malware Disturb/access information to transmit
 Worms Slow computer
 Browser Hijacker Redirect to other webs

7. How Computer Virus Spreads
 Email attachments
 Downloads
 Shared files
 Fake Websites
 Networks
 Infected hard disks / USBs
 Hackers/fake Anti Virus Software
 From Mobile Devices
 Friends and Relatives

8. How to identify Computer
Viruses
 Computer speaks to me
 Computer running extremely slow
 Applications won’t start
 Can’t connect internet or internet slows
 Antivirus disappeared, Firewall disabled
 Making .exe files
 Hide files
 System memory and disk space is
reduced
 New windows open up at an alarming
rate
 Error messages on regular basis

9. How to identify Computer
Viruses
 Format hard disk
 Copy, rename and delete files
 Modify files dates and extensions
 Display false message every few times
 Damage data
 Damage software
 Random restarts
 Unknown and uninstalled icons on
desktop
 Icons change in appearance

10. Prevention from Computer
Viruses
 Install reliable Anti-virus program
 Avoid opening suspicious websites
 Never opening attachment without
scanning
 Set-up automatic scanning
 Know what to look
 Install a firewall (Screening)

11. Antivirus
 Antivirus software is a computer program that
detects, prevents, and takes action to disarm or
remove malicious software programs, such as
viruses and worms.

12. Well-known Antivirus
Programs
 BitDefender Antivirus
 KasperSky Antivirus
 Norton Antivirus
 F-Secure Antivirus
 AVG Antivirus
 BullGuard Antivirus
 G Data Antivirus
 Panda Antivirus
 Avast Antivirus
 McAfee Antivirus

13. Well-known Antivirus
Programs
 There are so many anti-viruses which works against
viruses but some anti-viruses are trusted and are very
famous.
 There are 10 ranked anti-viruses by
toptenreviews.com
http://anti-virus-software-review.toptenreviews.com/

14. Conclusion :
Thank you – Questions ?
 References
• https://en.wikipedia.org/wiki/Computer_virus
• http://www.antivirusworld.com/articles/history.php
• http://www.articlesbase.com/information-technology-
articles/antivirus-history-277310.html
• http://videos.howstuffworks.com/harvard-extension-schools-
computer-science-e-1-understand/2736-desktop-firewalls-
video.htm
“In God we trust, all others we virus scan”
– Anon