The document provides an overview of computer viruses, detailing various types such as boot sector viruses, file infector viruses, and Trojan horses, along with their methods of operation. It explains how viruses replicate and damage data, and describes the operation of antivirus software in detecting and neutralizing these threats. The authors are Harem Abdullstar, Rebaz Abdullqadr, and Omer Muhammed, supervised by Mr. Aras Masoud.

1. UNIVERSITY OF SORAN
Faculty of science & engineering
School of engineering
DPT of petroleum engineering
VIRUS
Prepared by:
Harem Abdullstar
Rebaz Abdullqadr
Omer Muhammed
Supervisor :
Mr. Aras Masoud

2. Contents?
what's a computer virus ?
Types of Viruses
Categories of Viruses
How do viruses work?
How an Antivirus works?
Conclusion

3. What is a virus?
A computer virus is a computer program that
can copy itself and infect a computer without
permission or knowledge of the user.
The computer viruses can damage or
corrupt data, modify existing data .

4. Types of virus
Boot sector Virus
Master Boot Record virus (MBR)
File infector virus
 Multipartite virus
 Macro Virus
Trojan Horse
 Worms
Logic Bombs
Polymorphic Virus

5. 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.
E.g. Form, Disk
Killer, Michelangelo, Stoned.

6. Master Boot Record virus (MBR)
MBR viruses are memory-resident viruses
that infect disks in the same manner as
boot sector viruses.
E.g. AntiEXE, Unashamed, NYB

7. File infector virus
File infector viruses infect program files.
Normally infect executable code, such as
.COM, .SYS, .BAT and .EXE files.
E.g. Snow.A, Jerusalem, Cascade

8. Multipartite virus
A multipartite virus is a virus that can infect either
boot sectors or executables.
When it infects a boot sector, it works as a boot
sector infector.
E.g. One_Half, Emperor, Anthrax, Tequilla.

9. Macro Virus
Macro viruses infect files that are created using
certain applications or programs that contain
macros.
They infect documents created from Microsoft
Office Word, Excel, PowerPoint and Access files.
E.g.W97M.Melissa, Bablas, WM.NiceDay, W97M.
Groov.

10. Trojan Horse
A Trojan horse is a computer program that is
hiding a virus or other potentially damaging
program.
Trojan horses can be included in software that
you download for free or as attachments in
email messages.
E.g. Trojan.Vundo. Back
Orifice, NetBus, SubSeven

11. Worms
A computer worm is a self-replicating computer
program. It uses a network to send copies of
itself to other and it may do so without any user
intervention.
Work of worms
delete files on a host system
send documents via email
E.g.W32.Mydoom.AX@mm

12. How do viruses work?
Replicating itself
Interrupting system/network use
Modifying configuration settings
Flashing BIOS
Format hard drive/destroy data
Using computer/network resources

13. How an Antivirus works?
The antivirus software examines each and every
file in a computer and examines its content with
the virus definitions stored in its virus dictionary.
E.g. Avira
Kaspersky
Norton
Many more ……………

14. Thanks for your attention