What are Viruses and Why Should we use Anti Virus Software?

Computer viruses are a fact of modern, internet-connected life. At best, they’re annoying performance sucking beasts, but at worst … kiss all your data good bye.

We all need to take steps to make sure that our computers are safe, or we risk infection. Complacency is not an option.

And yet, even after all the news, and all the warnings, and after all this time …complacency remains all too common.

Here we have included some information which we help you to understand why anti virus software is a MUST for your computer and how you can save yourself time, heartache and money……. and well, anti virus software is available online FREE… so what excuse do you have ?:

What are Viruses?

Computer viruses are self-executing, replicating programs written specifically to change the way a machine works, without the knowledge (or permission) of the operator/owner. Viruses are so called because they behave in a similar way to biological viruses. Just as biological viruses pass from person to person, replicating themselves as they go, computer viruses pass from computer to computer. Unlike most biological viruses, however – computer viruses are entirely man made.

Viruses can impair and seriously damage your computer by, amongst other things; executing random text, audio and video messages, draining memory, deleting files, corrupting programs – even reformatting (or erasing the contents of) your hard disk. At best, the less destructive viruses are annoying and will slow the infected machine up (because of the drain on memory), often resulting in crashes and other unpredictable behaviour which can ultimately result in loss of data.

Although a virus needs an infected application to be launched in order to infect other programs or documents, they can hide themselves in your computer (often as innocent files) and replicate (make copies of) themselves until the infected application is launched.

Not all viruses behave in exactly the same way, and not all malicious programs are viruses (like Trojans). Some viruses are only active when the infected application is running, whilst others will stay active in memory until you turn off your computer. However, as the virus is resident in a file or on a disk, exiting the infected application or turning off your computer only removes the virus from memory, it does not remove the virus from the infected file or disk and the virus just lays dormant, until you to reboot your computer and/or access the infected application.

The various forms of computer viruses:

Boot sector viruses infect the boot sector of a hard drive or floppy disk by first overwriting/moving the original boot code and then moving the original code to another sector on the disk, which the virus marks as bad.

File infecting viruses attach/modify any executable files, sometimes replacing the original code with its own.

Macro viruses are self replicating macros that self replicate and can spread rapidly on a computer and/or network.

Master Boot Record Infectors infect a system’s Master Boot Record on hard drives and the Boot Sector on floppy diskettes.

Multi-partite viruses are commonly a combination of techniques of both boot sector viruses and file infecting viruses.

Polymorphic viruses are difficult to detect as they use an encryption algorithm that changes, along with the viruses’ appearance, change their appearance with/after each infection.

Stealth viruses hide themselves from a computers’ operating system and anti-virus products.

Viruses (including worms) are often distributed via attachments in e-mail spam and, ironically, a great deal of e-mail spam (particularly chain letters) are virus hoaxes.

Computer viruses, worms and Trojans

What they are and what they can doWorms are computer programs that can copy themselves from machine to machine, extremely quickly, through computer networks.

Computer worms differ from computer viruses because they run independently and do not need a host file, boot sector or file transfer between machines to propogate.

Worms:There are different types of computer worms that spread through various services – including e-mail and instant messaging clients.E-mail worms
These are spread via infected e-mail messages in the form of an attachment or link to an infected Web site – some e-mail worms will also spoof e-mail addresses.

IM worms
These are spread via instant messaging clients, to entire contact lists, in the form of links to infected Web sites.

Internet worms
These are spread when the Internet worm scans, tries to connect and, if successful gains access to any vulnerable machines – either by scanning the Internet and/or using the local operating system.

IRC worms
These are spread via IRC channels in the form of infected files or links to infected Web sites.

File-sharing Networks Worms
These are spread from shared folders via the P2P network.

After Installing Anti Virus Software – What Should I Do?

Update the Anti-Virus Database

Your first step should be to update the virus signature database that came with the installation. New viruses are being created every day, and the databases that the anti-virus programs use are being updated as well. You need to get the latest database for your program right away.

Most of the programs have update functions that will locate, download and install the latest databases automatically. Make sure that this is enabled.

Run Regular Scans

Most of the anti-virus programs work automatically. Once installed they are configured to scan all incoming and outgoing files, and often hook into your email in some way to double check that your received email is clean as well.

Unless you know what you’re doing, make sure that this “real time” scanning is enabled.

I also recommend periodically running scans of your hard disk(s). Certainly when you first install the software you should run a full scan. Then, depending on how heavily used your machine is, you should run a scan periodically as well.

Some programs will allow you to schedule such a scan to happen automatically. In my case, for example, since my computers are on 24 hours a day, I schedule full virus scans nightly, while I’m asleep.

Keep Windows Up-To-Date

Windows Update regularly, or simply enable the automatic update feature in Windows XP.

All software has bugs. Some of those bugs are used to create the exploits that virus writers take advantage of to create viruses that can infect your system. As these bugs are found, Microsoft fixes the affected components in the operating system, and makes those fixes available for download and install using Windows Update.

The “problem”, is that even once the bugs are discovered and publicized, and even when the fix is available, virus writers get busy writing viruses that still exploit them. Why? Because they know not everyone stays up-to-date.

Keep Windows up-to-date. Let someone else have the “fun” of being infected with the latest viruses.

Additional Notes

Sadly, there is no “best” anti-virus program. Each may miss some something that the other’s catch. That’s one of the reasons We have listed several. The best advice is to use one, any one, and have the others “on call” for those cases when spyware sneaks past the one you use regularly.

If you do install more than one package, you should not enable the “real time” scanning for more than one at the same time – they will conflict with each other, and will cause unpredictable results.

Basic anti-virus tips

  • Keep your anti-virus software up to date
  • Run your anti-virus software regularly
  • Use a firewall
  • Update & apply patches to close vulnerabilities