The document discusses computer viruses including their definition, types, symptoms, methods of infection, and prevention techniques. A computer virus is a malicious program that can self-replicate and spread between computers without the owner's permission. Common types include worms, Trojan horses, and botnets. Signs of infection include computers not booting, slow performance, and random crashing. Viruses primarily spread through email attachments, rogue websites, and infected removable drives. Regular scanning and software/OS updates can help prevent virus infections.

1. © 2012 Charmaine S. Camilo. All rights
reserved.

2. © 2012 Charmaine S. Camilo. All rights
reserved.

3. © 2012 Charmaine S. Camilo. All rights
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4. © 2012 Charmaine S. Camilo. All rights
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5. © 2012 Charmaine S. Camilo. All rights
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6. A computer virus is a caustic computer
program that can replicate itself and spread from
one computer to another without the permission of
the owner.
© 2012 Charmaine S. Camilo. All rights
reserved.

7. Viruses
Botnet Malware Worms
Trojan
Horse
© 2012 Charmaine S. Camilo. All rights
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8. • Worms
• Boot sector virus
• File infection virus
• Multipartite virus
• Network virus
• E-mail virus
• Macro virus
• Memory resident viruses
• Root kit virus
• Polymorphic viruses
• Logic bombs/Time bombs
© 2012 Charmaine S. Camilo. All rights
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9. The following are some possible indications
that a computer has been infected by a virus.
These problems can also be caused by non-virus
problems, but they are the most reported
symptoms of a computer virus infection.
• Computer no longer boots up.
• Screens sometimes flicker.
• Computer runs slower then usual.
• PC speaker beeps periodically.
• System crashes for no reason.
• Files/directories sometimes disappear.
© 2012 Charmaine S. Camilo. All rights
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10. Virus writers have to balance how and when
their viruses infect against the possibility of being
detected. Therefore, the spread of an infection
may not be immediate.
Phases of Viruses
• Infection phase
• Attack phase
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11. • System Sectors/Boot Records
• Files
• Companion Files
• Macros
• Disk Clusters
• Batch Files
• Source Code
• Visual Basic Worms
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12. 1. Email attachments.
2. Rogue Websites.
3. Networks
4. Infected Boot Disks
5. Phishing Schemes
6. Infected Software
7. Hackers
8. Instant Messaging
9. Fake Anti Virus Software
10. From Mobile Devices
11. Friends and Relatives
© 2012 Charmaine S. Camilo. All rights
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13. • Anti-virus software
• Scan your computer on a regular basis
• Update your anti-virus software on a regular basis
• Back-up
• Turn-off E-mail Preview
• Scan Removable disk
• Scan downloaded files
• Scan all e-mail attachments
• Beware of e-mail attachments from unknown
sources
• Be alert!
© 2012 Charmaine S. Camilo. All rights
reserved.

14. © 2012 Charmaine S. Camilo. All rights
reserved.

15. © 2012 Charmaine S. Camilo. All rights
reserved.