By: Tayyaba By: Tayyaba Farooq KhanFarooq Khan

Roll# 41Roll# 41

Computer Computer VirusesViruses

What is a Computer Virus?What is a Computer Virus?

A computer virus is a computer program that A computer virus is a computer program that can copy itself and infect a computer without the can copy itself and infect a computer without the permission or knowledge of the owner. permission or knowledge of the owner.

One of the first detected virus was the Creeper One of the first detected virus was the Creeper virus in the early 70’s virus in the early 70’s

Basic Computer VirusesBasic Computer Viruses

Trojan HorsesTrojan Horses appears as interesting program file but when installed appears as interesting program file but when installed

it allows intruders to access and read your filesit allows intruders to access and read your files WormsWorms

virus that copies and multiplies itself byvirus that copies and multiplies itself by using computer networks and securityusing computer networks and security flawsflaws

E-mail VirusesE-mail Viruses use e-mail messages to spread which allow it to use e-mail messages to spread which allow it to

automatically forward itself to thousands of peopleautomatically forward itself to thousands of people

Types of VirusesTypes of Viruses

Program VirusProgram Virus Becomes active when the program file (usually with Becomes active when the program file (usually with

extensions .BIN, .COM, .EXE, .OVL, .DRV) carrying the virus is extensions .BIN, .COM, .EXE, .OVL, .DRV) carrying the virus is openedopened

It then makes copies of itself and will infect other programs on It then makes copies of itself and will infect other programs on the computerthe computer

Multipartite VirusMultipartite Virus Hybrid of a Boot Sector and Program virusesHybrid of a Boot Sector and Program viruses It infects program files and when the infected program is active it It infects program files and when the infected program is active it

will affect the boot recordwill affect the boot record

Types of VirusesTypes of Viruses

Polymorphic VirusPolymorphic Virus Act like a chameleon, changing its virus signature (binary Act like a chameleon, changing its virus signature (binary

pattern) every time it multiples and infects a new filepattern) every time it multiples and infects a new file

Macro VirusMacro Virus Programmed as a macro embedded in a document, usually Programmed as a macro embedded in a document, usually

found in Microsoft Word and Excelfound in Microsoft Word and Excel Once it gets in to your computer, every document you produce Once it gets in to your computer, every document you produce

will become infectedwill become infected Relatively new type of virus and may slip by your antivirus Relatively new type of virus and may slip by your antivirus

software if you don't have the most recent version installedsoftware if you don't have the most recent version installed

Signs Your Computer is InfectedSigns Your Computer is Infected

Functions slower than Functions slower than normalnormal

Responds slowly and Responds slowly and freezes oftenfreezes often

Restarts itself oftenRestarts itself often See uncommon error See uncommon error

messages, distorted messages, distorted menus, and dialog boxesmenus, and dialog boxes

Notice applications fail to Notice applications fail to work correctlywork correctly

Fail to print correctlyFail to print correctly

First half of the 70'Late 60,s, early 70,s- "Rabbits" cloned First half of the 70'Late 60,s, early 70,s- "Rabbits" cloned themselves occupied system resources, slowing down the productivity. themselves occupied system resources, slowing down the productivity.

-"The Creeper" capable of entering a network by itself and transferring a -"The Creeper" capable of entering a network by itself and transferring a copy of itself to the system.copy of itself to the system.

Early 80,s-Increasing number of programs written by individuals not by Early 80,s-Increasing number of programs written by individuals not by software companies. Programs caused miner viruses called "Trojan horses".software companies. Programs caused miner viruses called "Trojan horses".

1986'Brain virus' - by Amjad and Basit Farooq Alvi. 1986'Brain virus' - by Amjad and Basit Farooq Alvi.

- spread through floppy disks, spread through floppy disks,

- infected boot records and not computer hard drivesinfected boot records and not computer hard drives Lahore, Pakistani Brain, Brain-A and UIUC virus Lahore, Pakistani Brain, Brain-A and UIUC virus

-took over free space on the floppy disk and hid from detection -took over free space on the floppy disk and hid from detection ”disguised itself by displaying ”disguised itself by displaying the uninfected boot sector on the disk.”the uninfected boot sector on the disk.”

1987-Lehigh virus1987-Lehigh virus

- the first memory resident file infector that attacked executable files and - the first memory resident file infector that attacked executable files and took control when a file was openedtook control when a file was opened

20062006 Discovery of the first-ever malware trojan horse for Discovery of the first-ever malware trojan horse for

Mac OS XMac OS X 20082008

Torpig is a Trojan horse which affects Windows, Torpig is a Trojan horse which affects Windows, turning off anti-virus applications.turning off anti-virus applications. It allows others to access the computer, modifies It allows others to access the computer, modifies

data, steals confidential information and installs data, steals confidential information and installs malware on the victim's computer.malware on the victim's computer.

20092009 Conficker infects anywhere from 9 to 15 million Conficker infects anywhere from 9 to 15 million

Microsoft server systems.Microsoft server systems. French air force, Royal Navy warships and French air force, Royal Navy warships and

submarines, Sheffield Hospital network, UK submarines, Sheffield Hospital network, UK Ministry of Defence, German Bundeswehr and Ministry of Defence, German Bundeswehr and Norwegian Police were all affected. Norwegian Police were all affected.

Total Number of Viruses by year Total Number of Viruses by year January 1985 1 January 1985 1 January 1985 1 January 1985 1 January 1987 3 January 1987 3 January 1989 6 January 1989 6 January 1990 142 January 1990 142 January 1991 357 January 1991 357 January 1992 1,161 January 1992 1,161 January 1993 2,482 January 1993 2,482 January 1994 3,687 January 1994 3,687 January 1995 5,626 January 1995 5,626 January 1996 7,764 January 1996 7,764 January 1997 11,037 January 1997 11,037 January 1998 16,726 January 1998 16,726 January 1999 40,850 January 1999 40,850 January 2000 44,000 January 2000 44,000 January 2001 48,000 January 2001 48,000 January 2002 55,000 January 2002 55,000 January 2003 62,000January 2003 62,000

Did you know?Did you know?

One German newspaper One German newspaper tragically lost 2,000 tragically lost 2,000 pictures from its archive.pictures from its archive.

The perpetrator turned out The perpetrator turned out to be a 23-year-old Filipino to be a 23-year-old Filipino computer science student computer science student who more or less who more or less plagiarized all of his code.plagiarized all of his code.

The lack of laws in the The lack of laws in the Philippines covering Philippines covering computer crimes, he pretty computer crimes, he pretty much got away with his much got away with his crime. crime.

PreventionPrevention

Upload and use antivirus Upload and use antivirus softwaresoftware

Be aware of the e-mails Be aware of the e-mails and attachments you and attachments you openopen

Check for updates on Check for updates on antivirus software antivirus software regularlyregularly

Make sure antivirus Make sure antivirus software is installed software is installed correctlycorrectly