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Computerviruses

Learn about computer viruses, including how they operate, their types, prevention, and restoration methods. Explore various categories of noxious programs such as spyware, trojan horses, worms, and more.

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Computerviruses

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  1. Computerviruses Created by: Zoltán Homoki

  2. It operates just like a real virus • It destroys • Frideric Cohen made the first virus in 1983 • They wanted to use it in the army • The result was shocking

  3. Definition of viruses • Enter to the system without permission • Can reproduce itself • Destroy if the conditions materialize

  4. Why are they noxious ? • Use lot of source of energy • Cause program or data losing • Cause detriment • Need to work with itself

  5. Groups of the noxious programs • Viruses : - system virus - program virus - application virus • Other noxious programs : ( spyware, trojan horses, worms, ZIP-bomb, mutation viruses, hoax viruses ect. )

  6. System viruses • It starts first (before the loading of the operation system) • It attacks the Master Boot Record • Prevention: - Checking of the MBR ( you can adjust it in the BIOS ) - Use anti-virus program • Restoration: FDISK/MBR, anti-virus program

  7. Program virus • The virus can infect these files : - ( exe, com, sys, dll, pif, dot ect.) • The parts of the computer virus: - reproduction routine - activation routine - objective ( punitive ) routine

  8. Program virus

  9. Groups of the computerviruses according to : • Generations • Speed of infection • Objective ( punitive ) routine • Place ( in memory, in file )

  10. According to generations • First generation virus (simple spreading, easy decoding) • Stealth virus ( all is shown uninfected ) • Mutation virus ( while spreading it can change itself)

  11. According to speed of infection • Viruses with slow infection : - just one or two victim • Viruses with fast infection : - it infects all opened files

  12. According to objectiv routin • Destroyer : - physically destroying - strongly destroying - partially destroying - selectively destroying • Not Destroyer : - show a text, a music, a picture - change the keys on the keyboard - there is not objective routin in it

  13. According to place • Resident: ( it there is in the memory till the computer is running ) • Not Resident • Mixed: ( objective routine resident, reproduction routine resident )

  14. Other noxious programs • Trojan horse ( Backdoor virus ): - It masks itself a normal program - It opens a backdoor in the operation system • For example.: SubSeven, NetBus, Backdoor.Amasso ect.

  15. Other noxious programs • Worm : - It use the operation system’s mistakes - It want to get information - It is not deleted - Just the operation system’s mistakes are fixed

  16. Other noxious programs • Virusgenerator : - You not have to be a programmer

  17. Other noxious programs • IN THE WILD ( ITW ) virus : • Circulates on the Internet • It is the most dangeruos

  18. Other noxious programs • ZOO - virus : • These viruses are made in the laboratories • It helps with making of better anti-virus software • There aren’t perfect anti-virus programs

  19. Other noxious programs • Hoax – virus : - These viruses make defective reports - They can’t cause mistakes

  20. Other noxious programs • ZIP- bomb : • In fact it is a very huge file • It is packed excellently • 1050 piece A type

  21. Other noxious programs • Spyware : ( Adware, Keylogger ) • Collectes information about you and your habits • Causes trouble ( frost the system, starts the IE with unknown home page, popup windows, strange icons on the desk ) • They are in Freeware and Shareware programs

  22. Adware • In the most of case its serves the aim of advertisment • Sends pieces of information about the users

  23. Keylogger • It can watch what you do on the computer • It registers the pressed down buttons • It sends the information to the sender • For example: BigBrother. FamilyCam

  24. Other noxious programs • SPAM: • Undesirable advertisment e-mails • The quantity of spam mails always grow • The e-mail traffic’s 75 per cent is spam - It is expensive to filter the spams

  25. Tricks of the spam senders • Open – relay ( mail server ) • Proxy server • WEB BUG • SPAM mails cheat the spam filters

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