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uCertify provides virus information as a reminder to all computer users to be on the alert...
A virus is a malicious program. A computer virus passes from one computer to another in the same way as a biological virus passes from one person to another. Most viruses are written with a malicious intent, so that they can cause damage to programs and data in addition to spreading themselves. Viruses infect existing programs to alter the behavior of programs, actively destroy data, and perform actions on storage devices that render their stored data inaccessible.
Computer viruses attack the software of a computer such as operating systems, data files, application software, and e-mails. However, viruses do not affect the computer hardware.
Viruses infect computers and spread themselves using various methods. Some viruses attach themselves to a common program such as a popular game or word processor. When a person downloads the infected game and runs it, the attached virus program gets executed. The virus then loads itself into memory and searches for any other programs on the drive. If the virus finds any programs, it can potentially modify those programs by adding the malicious code to those as well. The next time this program gets executed, it infects other programs, and the cycle continues thereafter.
Types of Computer Virus
There are many types of computer viruses such as a boot-sector virus, macro virus, e-mail virus, etc.
A boot-sector virus infects the boot record on hard disks and floppy disks, which is used to start the computer. When the computer is turned on or restarted, the virus is automatically executed. An infected boot disk may prevent the computer from starting at all.
A macro virus is a macro or script that attaches itself to a file or template. When the file is loaded, the instructions of the macro or script are executed. Most notable carriers of a macro virus is Microsoft Excel and Microsoft Word.
An e-mail virus moves around in e-mail messages, and usually replicates itself by automatically mailing itself to any email addresses in the victim's e-mail address book.
There are other types of programs also harmful to computers, which are not viruses such as a Trojan horse. The main difference between a virus and a Trojan horse program is the Trojan horse does not replicate itself -- it disguises itself as a legitimate program such as a game or utility. It often looks and initially acts in the same way as a legitimate program, but when it is executed, it destroys or corrupts data. A Trojan horse program can contain viruses, but it is not a virus itself.
Worms use computer networks and security holes to replicate itself. A Worm scans the network for another computer that has a specific security hole. It copies itself to the new computer using the security hole, and then starts replicating from there as well. A virus can have worm characteristics.
There are several anti-virus software that can detect, identify, and remove these viruses. As a precaution against viruses, we should take the following actions:
* An anti-virus software that can detect, identify, and remove viruses should be installed on the computer.
* All information downloaded from the Internet or some unknown resource must be immediately scanned for viruses by using an anti-virus software.
* Any e-mail attachment that comes from unknown sources should never be opened.
title = What is Virus?
author = Team uCertify
url = http://www.ucertify.com
dept = Home EDU: learning, reference, resources, etc.
audience = Computer users; specifically, Windows computer user
uCertify was formed in 1996 to offer high quality educational training software and services in the field of information technology to its customers. uCertify provides exam preparation solutions for the certification exams of Microsoft, CIW, CompTIA, Oracle, Sun and other leading IT vendors. To know more about uCertify, please visit http://www.ucertify.com
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