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Viruses

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This presentation is prepare by Polite group from GCU Faisalabad.The members of polite group are Syed Mubashair Abid.Ch.Junaid Arshad.Ch.Uzair Zia.Hafiz Jawad Ahmed.

This presentation is prepare by Polite group from GCU Faisalabad.The members of polite group are Syed Mubashair Abid.Ch.Junaid Arshad.Ch.Uzair Zia.Hafiz Jawad Ahmed.

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  • 1. Represented By Polite Group Focus on Target
    • Members of group
    • Junaid Arshad
    • Mubashair Abid
    • Hafiz Jawad Nadeem
    • Uzair Zia
  • 2. Topic of Discussion
    • VIRUS
  • 3. Contents
    • What is a computer virus?
    • Types of virus
    • How to spread a virus?
    • Properties of virus
    • Symptoms of Computer virus
    • Action of virus
    • Some other software acts as a virus
    • Steps to help avoid viruses
  • 4. What is a computer virus?
    • Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation.
    • Like a human virus, a computer virus can range in severity. It can damage your hardware, software or files.
    • Viruses can also replicate themselves.
    • A virus is dependent upon the host file or boot sector, and the transfer of files between computers to spread
  • 5. Types of virus
    • There are two main types of virus.
    • (1) Residential
    • (2) Non-residential .
  • 6. Residential
    • A VIRUS doing same thing with the help of Operating system and memory called Residential virus.
    • A type of computer virus that does not store or execute itself from the computer memory.
  • 7. Non-residential .
    • Those viruses searching new file to affect called Non-residential virus.
    • A type of computer virus that store or execute itself from the computer memory.
  • 8. How to spread a virus
    • A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk.
    • Computer viruses are often spread by attachments in e-mail messages or instant messaging messages. That is why it is essential that you never open e-mail attachments unless you know who it's from and you are expecting it.
    • Viruses can deceit us as attachments of funny images, greeting cards, or audio and video files.
    • Computer viruses also spread through downloads on the Internet . They can be hidden in illicit software or other files or programs you might download.
  • 9. Properties of Virus
    • Your computer can be infected by a virus even if files are just copied. Because some viruses are memory resident, as soon as a diskette or program is loaded into memory, the virus then attaches itself into memory and then is capable of infecting any file on the computer you have access to.
  • 10. Symptoms of Computer virus
    • Deleted files.
    • Various messages in files or on programs.
    • Changes volume label.
    • Marks clusters as bad in the FAT.
    • Randomly overwrites sectors on the hard disk.
    • Replaces the MBR with own code.
    • Create more than one partition.
    • Attempts to access the hard disk drive, which can result in error messages such as:
    • Invalid drive specification .
  • 11. Symptoms of Computer virus
    • Causes cross-linked files.
    • Causes a "sector not found" error.
    • Cause the system to run slow.
    • Logical partitions created, partitions decrease in size.
    • A directory may be displayed as garbage.
  • 12. Symptoms of Computer virus
    • After you open and run an infected program or attachment on your computer, you might not realize that you've introduced a virus until you notice something isn't quite right.
    • Here are a few primary indicators that your computer might be infected:
    • Your computer runs more slowly than normal
    • Your computer stops responding or locks up often
    • Your computer crashes and restarts every few minutes
  • 13. Symptoms of Computer virus
    • Your computer restarts on its own and then fails to run normally
    • Applications on your computer don't work correctly
    • Disks or disk drives are inaccessible
    • You can't print correctly
    • You see unusual error messages
    • You see distorted menus and dialog boxes
  • 14. Action of viruses
    • How viruses may affect files
    • Viruses can affect any files; however, usually attack .com, .exe, .sys, .bin, .pif or any data files - Viruses have the capability of infecting any file; however, will generally infect executable files or data files, such as word or excel documents that are opened frequently and allow the virus to try infecting other files more often.
    • Increase the files size - When infecting files, virtues will generally increase the size of the file; however, with more sophisticated viruses these changes can be hidden.
  • 15. Action of viruses
    • It can delete files as the file is run - Because most files are loaded into memory, once the program is in memory the virus can delete the file used to execute the virus.
    • It can corrupt files randomly - Some destructive viruses are not designed to destroy random data but instead randomly delete or corrupt files.
    • It can cause write protect errors when executing .exe files from a write protected disk - Viruses may need to write themselves to files that are executed; because of this, if a diskette is write protected, you may receive a write protection error.
  • 16. Action of viruses
    • It can convert .exe files to .com files - Viruses may use a separate file to run the program and rename the original file to another extension so the exe is run before the com.
    • It can reboot the computer when executed - Numerous computer viruses have been designed to cause a computer to reboot, freeze, or perform other tasks not normally exhibited by the computer.
  • 17. Some other software acts as a virus
    • Worm
    • Trojan Horse
    • Spyware
  • 18. worm
    • worm
    • A program or algorithm that replicates itself over a computer network and usually performs malicious actions
  • 19. Trojan Horse
    • Trojan Horse
    • A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves
  • 20. Spyware
    • Spyware programs are different from viruses, some can behave like viruses and pose similar and other risks.
  • 21. Steps to help avoid viruses
    • Use an Internet firewall
    • Subscribe to antivirus software and keep it current.
    • Never open an e-mail attachment from someone you don't know.
    • Avoid opening an e-mail attachment from someone you know, unless you know exactly what the attachment is. The sender may be unaware that it contains a virus.
  • 22.  

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