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Virus and worms


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Virus and worms

  1. 1. Page 1
  2. 2. VIRUSES AND WORMS Page 2
  3. 3. VIRUSViruses are malicious programs that can cause damage to computer.A computer virus attaches itself to a program or file enabling it to spread from one computer to another leaving infections as it travels. Almost all viruses are attached to an executable file which means the virus may exist on computerbut it actually infect our systems unless we run or open the malicious program. Page 3
  4. 4. A virus cannot be spread without ahuman action (such as running aninfected file or program) to keep it going.A virus is spread by sharing files or sending emails with viruses as attachments in the email. Page 4
  5. 5. How they work:Basic structure:{ look for one or more infectable objects if (none found) exit else infect object}Doesn’t remain in memory, but executes all ofthe viral code at once then returns control to theinfected program Page 5
  6. 6. Ways to infect computer systems throughviruses.Boot Sector PenetrationMacros PenetrationParasites Page 6
  7. 7. WORMSA worm is similar to view by design and isconsidered to be a sub-class of a virus. Worms spread from one computer to another it hasthe capability to travel without any human action.It is an independent program that does not modifyother programs, but reproduces itself over and overagain until it slows down or shuts down a computersystem or network. Page 7
  8. 8. It uses computer network to spread itself.It consumes too much system memoryInfects the environment rather than specificobjectsWorms send a copy of itself to everyonelisted on your email address book.. Page 8
  9. 9. Difference between viruses and worms.A virus an worms are similar in that they are bothforms of malicious software. The virus code isinjected into the previously benign program and isspread when the program is run.Examples of virus carrier programs are games, e-mail attachments and animationsA worm is a malicious software which replicatesitself. A worm spreads from system to systemautomatically, but virus needs another program inorder to spread. Page 9
  10. 10. Characteristics of a WormEnhanced TargetingEnhanced SpeedEnhanced CapabilitiesEnhanced Destructive Power Page 10
  11. 11. Phases of a worm or virus operationDormant PhasePropagation PhaseTriggering PhaseExecution Phase Page 11
  12. 12. Types of virusesStealth VirusPolymorphic VirusParasitic VirusMemory-resident VirusBoot Sector Virus Page 12
  13. 13. Protecting your Computer SystemTo ensure that your OS is up-to-dateTo have antivirus software and make sure it hasthe capability to scan e-mail and files as they aredownload from the internetNeed to run full disk scans periodicallyUse a Firewall. Page 13
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