COMPUTER VIRUS

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Presenters: Muhammad Kamran Muahammad Imran Khan 2:48 AM 2 COMPUTER VIRUSES

Agenda : 

Agenda Introduction Virus basics History Virus Cycle Types of viruses Top 5 Anti virus Conclusion 2:48 AM 3

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INTRODUCTION Definition is "a computer virus is a computer program that can infect other computer programs by modifying them in such a way as to include a (possibly evolved) copy of itself". 2:48 AM 4

Basic virus terminology : 

Basic virus terminology Virus Self-replicating Also called a worm Trojan Horse A program which appears to be valuable but has an unexpected consequence 2:48 AM 5

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Computer viruses are man-made programs that perform harmful operations (destroy data, files, software) and can reproduce and spread new copies. Specialists' definitions: WORM VIRUS TROJAN HORSE What is what..? 2:48 AM 6

History : 

History 1981 first Apple virus spreads through Texas A&M via pirated computer games 1983 definition of a computer virus (Fred Cohen) 1988 first major outbreaks (all macs) 1990 Symantec launches Norton Antivirus 1991 first polymorphic virus 1994 first hoax 1995 Word viruses predominate 1996ff Window viruses predominate 1999 first virus activated by opening email rather than attachment 2:48 AM 7

History(cont) : 

History(cont) 2000 Love bug. Stage = first virus with attachment disguised with .txt suffix. 2001 Nimda,SirCam & Code Red 2002 Klez,Bugbear 2003 first virus-generated spam 2004 My Doom Olympic Torch virus hoax   RINBOT computer virus 2008 Endgame 2009 Bealzibubuh 2010 Red Ohare 2:48 AM 8

How viruses get into computers : 

How viruses get into computers The four most common virus infections come from: File – A virus type that infects existing files on the computer (~40%) Macro – A virus that runs as a macro in a host application such as the MS Office applications (~20%) VBScript – A virus that uses Windows Visual Basic Script functionality (~10%) Internet Worm – A virus that is primarily characterized by it’s replication across the Internet (~20%) 2:48 AM 9

The life cycle of a virus : 

The life cycle of a virus A virus enters the system passively, through an activity of the operator (inserting an infected disk, opening an infected mail attachment). A virus has to be compatible with the system to gain a foothold. A virus replicates at the cost of computer speed. Damage causes loss or inaccessibility of files, and sometimes loss of the complete hard disk. Transfer to the next computer can occur automatically when computers are interconnected, or requires human activity such as sharing of diskettes. Entry Foothold Replication & Damage Transfer to next host 2:48 AM 10

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Did you know? : 

Did you know? An Email without an attachment until recently could not be a virus, and could not do harm. Virus attachments that were not opened until recently could not cause harm. Hardware is never damaged by viruses (although hard disks can become inaccessible). A Hoax is an Email that warns against a non-existing virus. Hoaxes are a nuisance because they take up resources but, until recently, they were harmless. You should always check if a message is a hoax before forwarding it. 2:48 AM 13

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Don’t open files that you are not expecting Many viruses automatically send files without the e-mail account owner’s knowledge. Ask the sender to confirm unexpected files. Suspect messages that appear more than once in your Inbox You may receive the same e-mail from a virus repeatedly. Basic virus defense 2:48 AM 14

Examples of risky file types : 

Examples of risky file types The following file types should never be opened: .EXE .PIF .BAT .VBS .COM 2:48 AM 15

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Virus Encyclopedia: Types of Viruses 2:48 AM 16

TYPES OF VIRUSES : 

TYPES OF VIRUSES ARMORED VIRUS CAVITY VIRUS COMPANION VIRUS RESIDENT VIRUSE POLYMORPHIC VIRUS STEALTH VIRUSE FAT VIRUS SELF-MODIFICATION VIRUS LOGIC BOMBS THE TROJAN HORSE VIRUS 2:48 AM 17

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An ARMORED virus is one that uses special tricks to make tracing, disassembling and understanding of its code more difficult. Like a Whale virus. ARMORED VIRUS 2:48 AM 18

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A Cavity virus is one which over writes a part of the host file that is filled with a constant (usually nulls), without increasing the length of the file, but preserving its functionality. The Lehigh virus was an early example of a cavity virus. CAVITY Virus 2:48 AM 19

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On exit, the new program executes the original program so that things appear normal. On PCs this has usually been accomplished by creating an infected .COM file with the same name as an existing .EXE file. COMPANION VIRUS 2:48 AM 20 A companion virus is that virus which is not modifying the original file but execute new program.

Resident Viruses : 

Resident Viruses This type of virus is settle in the RAM memory. From there it can overcome and interrupt all of the operations executed by the system: corrupting files and programs that are opened, closed, copied, renamed etc. Examples are: Randex, CMJ, Meve, and Mrklunky 2:48 AM 21

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A POLYMORPHIC virus is one that produces varied but operational copies of itself. This is so that virus scanners will not be able to detect all instances of the virus. POLYMORPHIC Virus 2:48 AM 22

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Stealth virus is a file virus, that uses special techniques to hide its presence from users and also from virus scanners. Once the computer has been infected, the virus can make modifications to allow the computer to appear that it has not lost any memory and the file size has not changed. An example of a stealth virus is the Natas virus. Stealth Viruses 2:48 AM 23

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2:48 AM 24 FAT Virus This type of virus attack on the individual files or on the directories resulting information losses because this virus wipeout the information from the infected files.

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2:48 AM 25 Most modern antivirus programs try to find virus-patterns inside ordinary programs by scanning them for so-called virus signatures. A signature is a characteristic byte-pattern If a virus scanner finds such a pattern in a file, it notifies the user that the file is infected. Then the user can delete, "clean" or "heal" the infected file. These viruses modify their code on each infection so each infected file contains a different variant of the virus. Self-modification

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2:48 AM 26 They are not considered viruses because they do not replicate. They are not even programs in their own right but rather secret segments of other programs.Their objective is to destroy data on the computer once certain conditions have been met. Logic bombs go undetected until launched, and the results can be destructive. Logic Bombs

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2:48 AM 27 Another unsavory breed of malicious code are Trojans or Trojan horses, which unlike viruses do not reproduce by infecting other files, nor do they self-replicate like worms. Trojan Horses

Anti-virus warnings : 

Anti-virus warnings 2:48 AM 28 Most of the time, the virus software will detect and prevent the infection. However, the help desk can better tell you what to do.

Immunity has costs : 

Immunity has costs Immunity uses resources and energy and thus is costly for the host. Similarly, computer-virus awareness is costly in terms of time and resources: Making back-ups Routine screening of attachments and discs Requesting confirmation from sender before opening an attachment 2:48 AM 29

TOP 5 ANTI VIRUS SOFTWARES : 

TOP 5 ANTI VIRUS SOFTWARES MCAFEE VIRUS SCAN AVG ANTIVIRUS ACTIVE VIRUS SHIELD ESET NOD 32 AVIRA ANTI VIR 2:48 AM 30

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Conclusion : 

Conclusion Computer viruses are human invention and now they are spreading and growing day by day so there is only way to protect your PC and that is antivirus soft-wares but up to dated. 2:48 AM 32

SOURCES OF THE PRESENTATION : 

SOURCES OF THE PRESENTATION 2:48 AM 33 http://www.google.com.pk/search?hl=en&defl=en&q=define:viru http://en.wikipedia.org/wiki/Computer_virus http://www.google.com.pk/images http://en.wikipedia.org/wiki/Virus http://www.authorstream.com/Presentation/ankit22kh-138050-antivirus-usage-education-ppt-powerpoint/

THANK YOU VERY MUCH… : 

THANK YOU VERY MUCH… 2:48 AM 34

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Q..? 2:48 AM 35