This document discusses computer viruses, including their definition, how they work, and common types. It defines a computer virus as a program designed to damage or disrupt normal computer functions by attaching itself to files and replicating. Common types of viruses discussed are boot sector viruses, which infect the boot sector to guarantee execution, executable viruses which are attached to legitimate programs, and email viruses which replicate by sending themselves to email contacts. Methods of prevention include keeping systems updated, using antivirus software, and using more secure operating systems. Examples of specific viruses mentioned are Melissa, ILOVEYOU, and MyDoom.

1. Computer VirusesComputer Viruses
Govt. engineering collageGovt. engineering collage
Rewa M.P.Rewa M.P.
Submitted to:- Dr. Manoj ChauhanSubmitted to:- Dr. Manoj Chauhan
Submitted by :- Saurabh MishraSubmitted by :- Saurabh Mishra
EE 2018 2EE 2018 2ndnd
semsem
Govt. engineering collageGovt. engineering collage
Rewa M.P.Rewa M.P.
Submitted to:- Dr. Manoj ChauhanSubmitted to:- Dr. Manoj Chauhan
Submitted by :- Saurabh MishraSubmitted by :- Saurabh Mishra
EE 2018 2EE 2018 2ndnd
semsem

2. Definition of VirusDefinition of Virus
 A virus is a small piece of software thatA virus is a small piece of software that
piggybacks on real programs in order to getpiggybacks on real programs in order to get
executedexecuted
 Once it’s running, it spreads by insertingOnce it’s running, it spreads by inserting
copies of itself into other executable code orcopies of itself into other executable code or
documentsdocuments

4. VIRUSVIRUS
 A computer virus is a program that is designed to damage or disrupt theA computer virus is a program that is designed to damage or disrupt the
normal functions of your computer andnormal functions of your computer and
 its files.its files.
 Like biological viruses, computer viruses attach themselves to a host,Like biological viruses, computer viruses attach themselves to a host,
usually a program file, data file, or a fileusually a program file, data file, or a file
 in your computer's operating system. From here, it replicates itself,in your computer's operating system. From here, it replicates itself,
spreading the infection to other files.spreading the infection to other files.
 viruses are transmitted from computer to computerviruses are transmitted from computer to computer
 Viruses can find their way onto your computer in many different ways.Viruses can find their way onto your computer in many different ways.
 Viruses can be transmitted by email, in downloads from the internet,Viruses can be transmitted by email, in downloads from the internet,
through network connections, by floppythrough network connections, by floppy
 disks or by CDs, particular those that have been burnt on a computerdisks or by CDs, particular those that have been burnt on a computer
infected by viruses.infected by viruses.

5. Money flowMoney flow
 Pay per clickPay per click

6. How it works?How it works?
 The flood of incoming messages to the targetThe flood of incoming messages to the target
system essentially forces it to shut down, therebysystem essentially forces it to shut down, thereby
denying service to the system to legitimate users.denying service to the system to legitimate users.
 Victim's IP address.Victim's IP address.
 Victim's port number.Victim's port number.
 Attacking packet size.Attacking packet size.
 Attacking interpacket delay.Attacking interpacket delay.
 Duration of attack.Duration of attack.
 MyDoom – SCO GroupMyDoom – SCO Group

7. WANNA CRYWANNA CRY
 The WannaCry ransomware attack was a MayThe WannaCry ransomware attack was a May
2017 worldwide cyberattack by the WannaCry2017 worldwide cyberattack by the WannaCry
ransomware cryptoworm, which targetedransomware cryptoworm, which targeted
computers running the Microsoft Windowscomputers running the Microsoft Windows
operating system by encrypting data andoperating system by encrypting data and
demanding ransom payments in the Bitcoindemanding ransom payments in the Bitcoin
cryptocurrency. It propagated throughcryptocurrency. It propagated through
EternalBlue, an exploit in older Windows systemsEternalBlue, an exploit in older Windows systems
released by The Shadow Brokers a few monthsreleased by The Shadow Brokers a few months
prior to the attack.prior to the attack.

8. Typical things that some currentTypical things that some current
Personal Computer (PC) viruses doPersonal Computer (PC) viruses do
 Display a messageDisplay a message

9. Boot Sector VirusesBoot Sector Viruses
 Traditional VirusTraditional Virus
 infect the boot sector on floppy disks andinfect the boot sector on floppy disks and
hard diskshard disks
 By putting its code in the boot sector, aBy putting its code in the boot sector, a
virus can guarantee it gets executedvirus can guarantee it gets executed
 load itself into memory immediately, and itload itself into memory immediately, and it
is able to run whenever the computer is onis able to run whenever the computer is on

10. Executable VirusesExecutable Viruses
 Traditional VirusesTraditional Viruses
 pieces of code attached to a legitimatepieces of code attached to a legitimate
programprogram
 run when the legitimate program getsrun when the legitimate program gets
executedexecuted
 loads itself into memory and looks aroundloads itself into memory and looks around
to see if it can find any other programs onto see if it can find any other programs on
the diskthe disk

11. E-mail VirusesE-mail Viruses
 Moves around in e-mail messagesMoves around in e-mail messages
 Replicates itself by automatically mailingReplicates itself by automatically mailing
itself to dozens of people in the victim’s e-itself to dozens of people in the victim’s e-
mail address bookmail address book
 Example:Example: Melissa virusMelissa virus,, ILOVEYOU virusILOVEYOU virus

12. PreventionPrevention
 UpdatesUpdates
 Anti-VirusesAnti-Viruses
 More secure operating systemsMore secure operating systems
e.g. UNIXe.g. UNIX

15. ReferenceReference
 http://mirror.aarnet.edu.au/pub/code-red/newframes-small-log.gifhttp://mirror.aarnet.edu.au/pub/code-red/newframes-small-log.gif
 http://www.factmonster.com/ipka/A0872842.htmlhttp://www.factmonster.com/ipka/A0872842.html
http://www.faqs.org/faqs/computer-virus/new-users/http://www.faqs.org/faqs/computer-virus/new-users/
 http://www.mines.edu/academic/computer/viri-sysadmin.htmhttp://www.mines.edu/academic/computer/viri-sysadmin.htm

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THANK YOUTHANK YOU