What is a computer virus?
A computer virus is
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a piece of executable program, macro or script.
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that is able to replicate itself.
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It usually does damage to computers or computer networks.
Computer Viruses vs Biological Viruses
At the moment, computer viruses and biological viruses are different. But we do not know what future developments might be.
Where do computer viruses come from?
Computer viruses are written by people, who could be
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persons with a political agenda
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persons looking for cheap thrills to satisfy their egos
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disgruntled employees or ex-employees (or axed employees)
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persons in a war trying to sabotage their enemy's computer systems
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persons with malicious intent, including terrorists.
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How do computer viruses spread?
Computer viruses can be introduced to a computer and spread via anything that can store or transmit information. (e.g. network cables, CDs, zipped disks… etc).
Variations of viruses and other undesirable programs
It is impossible to classify all undesirable programs into distinct categories, but here are some common variations:-
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System-Sector Viruses - viruses that live in system sectors of computers
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"Macro" Viruses - viruses that live in macro-enabled documents
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Time Bombs - viruses that activate at a certain time or date
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Logic Bombs - viruses that activate when a certain condition is met
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Trojan horses - programs that appear good, but are actually destructive
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Worms - malicious programs that spread via computer networks
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Carriers
A computer may act as a carrier of a virus even though it may not be infected by the virus.
How are virus brought into your computer system?
Viruses can be brought in through many channels, including the following common methods:-
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by contact with virus-infected disks
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via downloaded files
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via electronic mail,
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via web-pages with embedded scripts or applets, or links to scripts or applets
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by an insider
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Prevention and Protection against malicious programs
Even though there is no 100% guarantee against being attacked by malicious programs, we, on our part, need to be vigilant. We can reduce our vulnerability to viruses or virus-like programs in the following ways:-
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Do not download or share programs or files indiscriminately.
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Use a good anti-virus program.
You can search for a anti-virus software yourself on the Internet using a search engine and you can also
shop for a anti-virus programs in computer software retail stores.
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Back up your work regularly!
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Be careful when viewing or previewing e-mail. Do not open mail from suspicious or unfamiliar sources; be wary of mail with suspicious content, even from known sources.
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Also:
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Write-protect diskettes and zip-disks except when putting information on them.
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Disable macros when opening documents
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Disable all cookies and scripts from your web browser.
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Stay on top of news and the latest developments
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Update your anti-virus software or virus definition list regularly.
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What to do if a virus is detected
If it is on a personal system:
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Try to use the anti-virus software to restore the infected files to their original state. If this is not possible, kill the virus first and copy back your data files from your back-ups.
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Test all other storage devices and delete all viruses found.
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Alert your friends and colleagues who may have picked up the virus from your system.
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If the virus is on a network system:
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Contact your network administrator immediately.
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Alert all your colleagues of the virus.
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Tell everyone to disable all file-sharing (if possible).
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Warn everyone to be careful with e-mails or attachments. |
Copyright© 2006 ASKnLearn Pte Ltd.
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