Computer virus


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a brief introduction about computer viruses, their types, how they spread and what precautions should be followed to stay unaffected.

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Computer virus

  1. 1. 11/7/2013 1Rabia Bibi
  2. 2. Rabia bibi 11777 COMPUTER VIRUSES 11/7/2013 2
  3. 3. Computervirus: Is a type of malware, designed to replicate itself by copying itself into the other programs stored in a computer. It may cause a program to operate incorrectly or corrupting a computer's memory. 11/7/2013 3Rabia Bibi
  4. 4. 11/7/2013 4RabiaBibi Malware: Software that is written and distributed for malicious purposes, such as impairing or destroying computer systems. Characteristics of computer viruses They are a piece of program or code. Executes without any permission or informing to user. Replicates, and made copies of themselves to spread. Some types require special command to replicate. can corrupt and distribute personal info of the user over internet. They are all men made.
  5. 5. 11/7/2013 5RabiaBibi Symptoms: • Computer functions slower than normal • Responds slowly and freezes often. • Often restarts itself. • See uncommon error messages, distorted menus, and dialog boxes. • Notice applications fail to work correctly. • Fail to print correctly.
  6. 6. 11/7/2013 Rabia Bibi 6 Sundus mukhtar 11800 History of computer virus
  7. 7. 11/7/2013 Rabia Bibi 7 1949, john von Neumann came up with the theory about self- replicating programs and “creeper” was the first Virus invented for experimental purpose. 1981 Apple Viruses 1, 2, and 3 are some of the first viruses in the public domain. Found on the Apple II operating system, the viruses spread through computer games. 1983 Fred Cohen, defines a computer virus as “a computer program that can affect other computer programs by modifying them in such a way as to include a (possibly evolved) copy of itself.” 1/30/2015 7Sundus mukhtar
  8. 8. 11/7/2013 Rabia Bibi 8 1986, 1998, the first PC virus, codename “The Brain” is released from Pakistan. . StrangeBrew is the first virus to infect Java files. The Chernobyl virus spreads quickly via .exe files the virus is quite destructive, attacking not only files but also a certain chip within infected computers. 2000 Tristate is the first multi-program macro virus; it infects Word, Excel, and PowerPoint files. “I Love You” virus appears. It managed to infect millions of computers in just under a day. 1/30/2015 8Sundus mukhtar
  9. 9. 11/7/2013 Rabia Bibi 9 2001 the Code Red virus posed a serious threat to the White House website. It infected tens of thousands of computers The same year, the Nimda virus hits the Internet. In the brief history of computer viruses this is one of the most sophisticated viruses ever to appear. 2005 March saw the world's first cell phone virus: Commwarrior-A. The virus probably originated in Russia, and it spread via text message. 2010 Stuxnet is a computer worm targeting Siemens industrial software through Microsoft Windows. 1/30/2015 9Sundus mukhtar
  10. 10. 11/7/2013 Rabia Bibi 1010ROLL NO: 11742
  11. 11. 11/7/2013 Bushra Khan 11 TYPES OF COMPUTER VIRUSES  Email virus  Worms  Trojan horses  Macro virus  Logic and time bomb virus  Boot sector 11 BUSHRA KHAN ROLL NO: 11742
  12. 12. 1/30/2015 Rabia Bibi 12 Email viruses • Email viruses first started showing up in the 1990s when the use of email became widespread. • Email virus is of two types: • Melissa virus • ILOVEYOU virus 12 BUSHRA KHAN ROLL NO: 11742
  13. 13. 11/7/2013 Rabia Bibi 13 MELISSA VIRUS • One of the most impressive viruses to hit computers was the Melissa virus, which happened in March 1999. 13 BUSHRA KHAN ROLL NO: 11742
  14. 14. 11/7/2013 Rabia Bibi 14 ILOVEYOU virus • Another notable email virus was called the ILOVEYOU virus, which infected computers on May 4, 2000. 14 BUSHRA KHAN ROLL NO: 11742
  15. 15. 11/7/2013 Rabia Bibi 15 Worms • A program that makes copies of itself; for example, from one disk drive to another, or by copying itself using email or another transport mechanism. 15 BUSHRA KHAN ROLL NO: 11742
  16. 16. 11/7/2013 Rabia Bibi 16 Types of worms Email Worms Instant Messaging Worms File-sharing Networks Worms 16 BUSHRA KHAN ROLL NO: 11742
  17. 17. 11/7/2013 Rabia Bibi 17 • BOOT SECTOR VIRUS • LOGIC BOMB VIRUS
  18. 18. 11/7/2013 Rabia Bibi 18 Definition A sector on the computer floppy disk drive, hard drive, or other bootable disk drive that contains instructs the computer on how to boot from the drive. There are two kinds of boot sectors - volume boot records and master boot records. IBM PC disk drives: IBM PC disk drive have different types of boot sectors • MBR (master boot record) which is the first sector of a portioned hard drive volume boot record. • VBR (volume boot record) which contains partition information at the beginning of each partition. 1/30/2015 12:03 PM 18Anamhassan
  19. 19. 11/7/2013 Rabia Bibi 191/30/2015 12:03 PM Anamhassan 19 Example with the help of diagram: In this example, the drive has two partitions; each partition contains its own VBR. When BIOS hands control over to the boot sectors, the MBR takes control and starts the boot process and refers to the VBR to point it to the partition information. Several major kinds of boot sectors could be encountered on IBM PC compatible hard disks, floppy disks and similar storage device.
  20. 20. 11/7/2013 Rabia Bibi 20 A boot sector virus is a computer virus that infects a storage device's MBR. It is not mandatory that a boot sector virus successfully boot the victim's PC to infect it. As a result, even non-bootable media can trigger the spread of boot sector viruses. These viruses copy their infected code either to the floppy disk's boot sector or to the hard disk's partition table. During start-up, the virus gets loaded to the computer's memory. As soon as the virus is saved to the memory, it infects the non-infected disks used by the system. The propagation of boot sector viruses has become very rare since the decline of floppy disks. 1/30/2015 12:03 PM 20Anamhassan What does Boot Sector Virus mean?
  21. 21. 11/7/2013 Rabia Bibi 211/30/2015 12:03 PM 21Anamhassan
  22. 22. 11/7/2013 Rabia Bibi 22 A logic bomb also called because all that's left after it detonates is computer slag, is not the same thing as a virus, although it often behaves in a similar manner. WORKING: It is a piece of computer code that executes a malicious task, such as: •Clearing a hard drive •Deleting specific files It's secretly inserted into the code of a computer's existing software, where it lies dormant until that event occurs. This event can be either Positive event Negative event SLAG CODE 1/30/2015 12:03 PM 22Anam hassan
  23. 23. 11/7/2013 Rabia Bibi 231/30/2015 22 SPEAKER: AMMARA FAROOQUI 11736
  24. 24. 11/7/2013 Rabia Bibi 24
  25. 25. 11/7/2013 Rabia Bibi 251/30/2015 25 TROJAN HORSES VIRUS • normal computer programs • pretends to be a regular downloadable program • incapable of replicating Ammara farooqui
  26. 26. 11/7/2013 Rabia Bibi 261/30/2015 26 CONT. most insidious types is that the program claims to rid your computer of viruses but instead introduces viruses onto your computer. Ammara farooqui
  27. 27. 11/7/2013 Rabia Bibi 27 271/30/2015 Ammara farooqui
  28. 28. 11/7/2013 Rabia Bibi 28 MACRO VIRUSES • written in a macro language • spread as an e-mail virus • depends on the application rather than the operating system 1/30/2015 28Ammara farooqui
  29. 29. 11/7/2013 Rabia Bibi 29 1/30/2015 29 CONT.. • "infects" a Microsoft Word or similar application • causes a sequence of actions to be performed automatically Ammara farooqui
  30. 30. SPEAKER: MADIHA AHMED ROLL NO: 11761 3011/7/2013 MADIHA AHMED
  31. 31. 11/7/2013 Rabia Bibi 31 Virus Entrance Attachment Of Virus Appearance Of Virus Execution Or Running Of Effected Program Computer System Get Effected With Virus 11/7/2013 31MADIHA AHMED
  32. 32. 11/7/2013 Rabia Bibi 32 There are literally dozens of ways for viruses to enter into the computer system. 11/7/2013 32MADIHA AHMED
  33. 33. 11/7/2013 Rabia Bibi 33 Virus attaches to its target file or software present in computer system . 11/7/2013 33MADIHA AHMED
  34. 34. 11/7/2013 Rabia Bibi 34 :It can appear in the form of code, scripts, active content, other software and email attachments. 11/7/2013 34MADIHA AHMED
  35. 35. 11/7/2013 Rabia Bibi 35 EXECUTION OR RUNNING OF PROGRAM REPLICATIO N 11/7/2013 35MADIHA AHMED
  36. 36. 11/7/2013 Rabia Bibi 36 11/7/2013 36MADIHA AHMED
  37. 37. 11/7/2013 Rabia Bibi 377/11/2013Noor-ul-ainn 37 Anti virus noor-ul-ainn roll no: 11 77 3 Noor-ul-ainn7/11/2013
  38. 38. 11/7/2013 Rabia Bibi 38 Definition: • “Antivirus" is protective software designed to defend your computer against malicious software. Malicious software, or "malware" includes: viruses, Trojans, key loggers, hijackers, dialers, and other code that vandalizes or steals your computer contents. In order to be an effective defense, your antivirus software needs to run in the background at all times. 7/11/20Noor-ul-ainn 38 P R O T E C T 7/11/2013
  39. 39. 11/7/2013 Rabia Bibi 39 Problems: • One of the most common reasons for failures or problems in computers is the lack of antivirus software, or expired antivirus software. • A few examples are provided below: • Computer run slowly itself. • Damage parts of the system or how the system operates without the owner's knowledge . • Be used to steal personal details . • receiving out unauthorized messages / emails. 7/11/2013 Noor-ul-ainn 39
  40. 40. 11/7/2013 Rabia Bibi 40 anti-virus: HOW IT WORKS ? • Anti virus software will constantly monitor the activity of all the programs. • If any program tries to write data on an executable file the antivirus software will flag the program having a suspicious behavior means the suspected programs will be marked as virus. 7/11/2013 Noor-ul-ainn 40
  41. 41. 11/7/2013 Rabia Bibi 41 So What Does Antivirus Software Do? • Antivirus software is the "policeman" at the gate of a computer system. It protects the computer from incoming threats and seeks out, destroys and warns of possible threats to the system. 7/11/2013 Noor-ul-ainn 41
  42. 42. 11/7/2013 Rabia Bibi 42 Cont.. New viruses are coming out all the time. It is the job of the antivirus software to keep up with the latest threats. This is achieved by daily updates of the antivirus data base,its purpose is to counteract the latest threats to provide constant protection. 7/11/2013 Noor-ul-ainn 42
  43. 43. 11/7/2013 Rabia Bibi 43 Examples: • Examples of common antivirus programs include Norton Antivirus, Kaspersky Anti-Virus, and ZoneAlarm Antivirus. slide 7 43antivirus
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  50. 50. 11/7/2013 Rabia Bibi 50  viruses-worst-today-case-wondering/    computer-viruses.html  look-at-the-history-of-computer-viruses.php  watch/ 
  51. 51. 11/7/2013 Rabia Bibi 51