This article is to create awareness within our membership on the various viruses currently in circulation and how to detect them and prevent your PCs being attacked and your databases being destroyed. Viruses are programs that you unwittingly store on your hard disk, where they can open and cause havoc. They are self replicating and may be passed from one PC to another. But you can take steps to minimize infection. Virus protection programs will destroy most viruses and help shield you from future infection.
A GUIDE TO VIRUSES
Macro Viruses are the most common, with names like Concept, Nuclear, and Laroux. They are written in a Macro - a sequence of instructions - attached to a Word or Excel file. If you open an infected document, the macro virus writes itself into your copy of Word or Excel, and then infects all future documents created by you. Some strains of Word macro virus propagate by e-mail, using Outlook Express to send copies of themselves to names randomly chosen from your address book.
Versions of Word and Excel from Office 97 onward warn you of the possible presence of macros in files to be opened and offer to disable them.
Boot-sector viruses were best known in the days of the Disk Operating System (DOS). They still exist in large numbers, surviving in your hard disk's boot sector - where the files used to start up your PC are stored. A boot sector virus becomes active each time you start up - or restart - your PC. Once active, it will copy itself onto every floppy disk inserted into your PC.
File-infecting viruses are also known as parasitic viruses. While they are more common under DOS, some Windows file viruses exist as well. They lurk inside a program .When you run it, the virus starts meddling with your RAM, and then infect the other programs that you run.
Viruses known as worms spread copies of themselves over networked computers. While they can replicate themselves and use memory, they can't spread by attaching themselves to other viruses. The notorious Internet Worm of 1988 spread to thousands of machines in a few days, and marked the first time that users were concerned about viruses over the Net.
A multipartite virus combines boot-sector and file-infecting viruses. It is found within an executable program. When the program is run, the virus infects the hard drive's boot sector.
Polymorphic viruses are viruses that attempt to escape detection by changing their form each time they spread.
Strictly speaking, Trojan horses are not viruses since they don't replicate. They tend to be hidden inside programs, usually games, and they display a message, erase files, or lose data.
You can get rid of them just by deleting them.
Script viruses are written in script programming languages, like Visual Basic Script and JavaScript.
They can be caught by opening a .vbs or .is file, or they can be embedded into the HTML or a web page. In theory, just opening a web page could cause infection, though there are no confirmed reports of this happening - yet.
In the next issue of Newsletter PAAM, we will discuss
the following aspects of prevention from virus:
i. Methods of infection
ii. How to avoid viruses
iii. Top 10 warning signs
To be continued ...
Source of the above article:
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The President's Message
