Isas

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Isas

  1. 1. INTRODUCTION• A Computer Virus is actually a computer program that can increase its own number by replicating itself and keeps on infecting the other files by changing their properties continuously.• It can be sent by various means such as over the internet, by email, or can be carried on various storage mediums such as Floppy, Portable Hard Disks, Pen Drives, Bluetooth, CDs & DVDs etc.
  2. 2. ETYMOLOGY• In 1984 Fred Cohen from the University of Southern California wrote his paper "Computer Viruses - Theory and Experiments“. It was the first paper to explicitly call a self-reproducing program a "virus", a term introduced by Cohens mentor Leonard Adleman.• The actual term "virus" was first used to denote a self-reproducing program in a short story by David Gerrold in Galaxy magazine in 1969 - and later in his 1972 novel, When HARLIE Was One.
  3. 3. HISTORY• In 1971, The Creeper was the first detected Virus on ARPANET, the forerunner of internet.• In 1981, A program called “Elk Cloner” was the first computer Virus that appeared outside the single computer or lab written by Richard Skrenta.• In 1986, The first PC Virus was a boot sector virus dubbed ©Brain created by Farooq Alvi Brothers in Lahore, Pakistan.
  4. 4. TYPES OF VIRUSWHAT THEY INFECT HOW THEY INFECTSystem Sector Virus Polymorphic VirusFile Virus Stealth VirusMacro Virus Fast and Slow InfectorsCompanion Virus Sparse InfectorsCluster Virus Armored VirusesBatch File Virus Multipartite VirusSource Code Virus Cavity VirusVisual Basic Worms NTFS ADS Virus
  5. 5. LOGIC OF VIRUS• It is easy to mess-up the right program. For example, if you remove even a single byte from an EXE file, that EXE file won’t be usable!• It’s a common practice to include ‘signatures’ by virus creators.• The main idea is to force the innocent user to run the programs.• Certain viruses come along with so called ‘programmer utilities’ or ‘free tools’.
  6. 6. EXAMPLEORKUT VIRUS / Muhaha Virusifwinactive ahk_classIEFrame{ ControlGetText,ed,edit1,ahk_classIEFrame soundplay,C:heap41a2.mp3 msgbox,262160,ORKUT IS BANNED you fool return}How this works is left to the readers to analyze.........
  7. 7. VIRUS-LIKE COMPUTER PROGRAM• Trojan Horse A Virus-Like Program pretends to do something else is Trojan.• Logic Bombs A logic bomb infects a computers memory but does not replicate.• Malicious software Virus-like programs that run within a web browser are called malicious software.
  8. 8. SIGNATURE OF VIRUSMany virus programmers add signature to their program. Soby checking the signature, we can find the name of the virus.Most of the anti-virus packages use this logic! Virus Signature Einstein 0042CD217231B96E0333D2B440CD2172193BC17515B80042 Pheonix 927 E800005E81C6????BF0001B90400F3A4E8 Spanz E800005E81EE????8D94????B41ACD21C784 Necropolis 50FCAD33C2AB8BD0E2F8 Trivial-25 B44EFEC6CD21B8??3DBA??00CD2193B440CD Trivial-46 B44EB120BA????CD21BA????B80?3DCD21%2BA0001 %4B440CD SK CD20B80300CD1051E800005E83EE09
  9. 9. PREVENTIVE MEASURES• Anti-Virus• Virus Removal Using System Restore• Operating System Re-Installation• System Software Update
  10. 10. ANTIVIRUS• Many users install anti-virus software that can detect and eliminate known viruses after the computer downloads or runs the executable.• The first, and by far the most common method of virus detection is using a list of virus signature definitions.• The second method is to use a heuristic algorithm to find viruses based on common behaviors.
  11. 11. EXAMPLES OF ANTIVIRUS• Avast• Kaspersky• Panda• Quick Heal• Mc Afee• AVG• Norten Antivirus
  12. 12. CONCLUSION• Computer Viruses are not just a threat to the modern technologies but also to the security of privacy.• Always use Anti-Virus Software to stay protected, and keep updating for signature updates.• It’s necessary to stay aware about it since we have a computerized digital future.

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