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WHAT IS A "VIRUS"?

WHAT IS A "VIRUS"?. Computer viruses are called viruses because they share some of the traits of biological viruses. A computer virus passes from computer to computer like a biological virus passes from person to person. WHAT IS A "VIRUS"?. BIOLOGICAL VIRUSES

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WHAT IS A "VIRUS"?

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  1. WHAT IS A "VIRUS"? Computer viruses are called viruses because they share some of the traits of biological viruses. A computer virus passes from computer to computer like a biological virus passes from person to person.

  2. WHAT IS A "VIRUS"? • BIOLOGICAL VIRUSES • A biological virus is not a living thing • A virus is a fragment of DNA inside a protective jacket • A biological virus must inject its DNA into a cell • COMPUTER VIRUSES • A computer virus must piggyback on top of some other program or document in order to get executed • Once it is running, it is then able to infect other programs or documents

  3. VIRUS HISTORY Traditional computer viruses were first widely seen in the late 1980s Viruses took advantage of these three facts to create the first self-replicating programs! FIRST FACTOR Spread of personal computers SECOND FACTOR Use of computer "bulletin boards" THIRD FACTOR The floppy disk

  4. CLASSES OF VIRUSES 1. FILE INFECTORS VIRUSES a. Embedded in program b. Runs when program gets executed c. Loads in memory d. Cycle continues through sharing files 2. BOOT-SECTORVIRUSES a. Load viruses into memory b. Infect the boot sector on floppy disks and hard disks 3. MACRO VIRUSES a. Infects data files b. Executed in embedded scripts c. Inserts copies of itself into other documents d. Spreads by sharing data files

  5. CLASSES OF VIRUSES EXECUTABLE AND BOOT SECTOR VIRUSES ARE NOT VERY THREATENING ANY MORE 1. Large size of today's programs (executable) 2. Operating systems now protect the boot sector

  6. E-MAIL VIRUSES E-MAIL VIRUSES ARE THE LATEST INVENTION • Melissa Virus (March 1999) • a. Embedded into Word document • b. When opened, sent to first 50 email addresses in address book • c. Included a friendly note making it look harmless • d. If opened by any of the recipients, sent to another 50 • addresses of the current recipient • The ILOVEYOU Virus (May 2000) • a. Attachment is a piece of code • b. When executed, sent itself to everyone in the address book • c. Corrupted files

  7. ORIGINS THREE REASONS PEOPLE CREATE VIRUSES • The same psychology that drives vandals and arsonists • The thrill of watching things destroyed • Bragging rights, or the thrill of doing it

  8. FIGHTING VIRUSES ANTIVIRUS PROGRAMS - Norton Antivirus (Symantec) - VirusScan (McAfee) - F-Secure Anti-Virus (F-Secure) No anti-viruses guarantee 100 percent protection from viruses!!!

  9. STATISTICS Position Name Number of occurrences 1 I-Worm.Klez 96.49% 2 Win95.CIH 0.84% 3 I-Worm.BadtransII 0.52% 4 I-Worm.Hybris 0.30% 5 Trojan.PSW.Delf 0.24% 6 I-Worm.Sircam 0.21% 7 Win32.Elkern.c 0.16% 8 Macro.Word.Cap 0.13% 9 Win32.FunLove 0.09% 10 I-Worm.Magistr 0.07%

  10. STATISTICS NUMBER OF INFECTED FILES BY COUNTRY, WITHIN THE LAST 30 DAYS 0-100 101-1000 1001-10,000 10,001-100,000 100,001+

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