Tutorial

KEEPING YOUR COMPUTER FREE OF VIRUSES

The rate at which viruses are attacking systems is becoming more alarming that something has to be done to educate the community on how to protect their system. Many have lost important files and even hard disk on account of this, that is why you can’t avoid to be complacent on this issue; you might be the next victim. A battle against Computer Viruses must be declared.

Before attack can be launched on these viruses, a clear understanding of what they are, what they do and how they are different from a WORM or TROJAN HORSE must be known.

What are Viruses?

A virus is a program or piece of code that is loaded into your computer without your knowledge and runs against your wishes. It is a man-made program that causes an unexpected, usually negative event on your system. It is designed to spread itself by first infecting executable files or the system areas of hard and floppy disks and then making copies of itself. Viruses usually operate without the knowledge or desire of the computer user.

How do they work?

A computer virus attaches itself to a program or file so it can spread from one computer to another, leaving infections as it travels. Much like human viruses, computer viruses can range in severity; some viruses cause only mildly annoying effects while others can damage your hardware, software or files. Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it cannot infect your computer unless you run or open the malicious program. It is important to note that a virus cannot be spread without a human action, (such as running an infected program) to keep it going.  People continue the spread of a computer virus, mostly unknowingly, by sharing infecting files or sending e-mails with viruses as attachments in the e-mail.

When you execute program code that is infected by a virus, the virus code will also run and try to infect other programs, either on the same computer or on other computers connected to it over a network. And the newly infected programs will try to infect yet more programs.

When you share a copy of an infected file with other computer users, running the file may also infect their computers; and files from those computers may spread the infection to yet more computers.

If your computer is infected with a boot sector virus, the virus tries to write copies of itself to the system areas of floppy disks and hard disks. Then the infected floppy disks may infect other computers that boot from them, and the virus copy on the hard disk will try to infect still more floppies.

Viruses are becoming more virulent as the imbeciles who create them turn more perverse in their creations. Some viruses will completely take over your computer, revising crucial files to control the operation of your programs. They can cut off your access to the Internet and to your key programs, making it impossible to update your virus protection software. They send infected email messages and attachments without your being aware of it.

How is a Virus differ from a Worm and a Trojan Horse

A worm is similar to a virus by its design, and is considered to be a sub-class of a virus, a variant of it. Worms spread from computer to computer, but unlike a virus, it has the ability to travel without any help from a person. Worms spread over a computer network on their own, infecting computers. A worm takes advantage of file or information transport features on your system, which allows it to travel unaided. The biggest danger with a worm is its ability to replicate itself on your system, so rather than your computer sending out a single worm, it could send out hundreds or thousands of copies of itself, creating a huge devastating effect. It is designed to copy itself from one computer to another over a network. Most worms appear as an e-mail, but sometimes users need only connect to the internet to become infected. One example would be for a worm to send a copy of itself to everyone listed in your e-mail address book. Then, the worm replicates and sends itself out to everyone listed in each of the receiver's address book, and the manifest continues on down the line. Due to the copying nature of a worm and its ability to travel across networks the end result in most cases is that the worm consumes too much system memory (or network bandwidth), causing Web servers, network servers, and individual computers to stop responding. In more recent worm attacks such as the much talked about .Blaster Worm., the worm has been designed to tunnel into your system and allow malicious users to control your computer remotely. It searched the internet for software flaws to gain admittance to computers.

A Trojan Horse is full of as much trickery as the mythological Trojan Horse it was named after. The Trojan Horse, at first glance will appear to be useful software but will actually do damage once installed or run on your computer.  Those on the receiving end of a Trojan Horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source.  When a Trojan is activated on your computer, the results can vary. Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system. For example, you might download what you think is a new program; but when you run it, it deletes files on your hard drive. Or the third time you start the program, the program e-mails your saved passwords to another person. Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.

Indication of the Presence of Virus

How can you know if your system has been infected with Viruses, Worm or even a Trojan Horse?

You will know you have an infected Computer if you suddenly can’t perform certain procedures like:

• Can’t connect to the Internet .
• Can’t run your anti-virus software
• Can’t run your e-mail program

There are also a number of symptoms which indicate that your computer has been infected. If you notice "strange things" happening to your computer, namely:

• unexpected messages or images are suddenly displayed
• unusual sounds or music played at random
• your CD-ROM drive mysteriously opens and closes
• programs suddenly start on your computer
• you receive notification from your firewall that some applications have attempted to connect to the Internet, although you did not initiate this, then it is very likely that your computer has been infected by a virus

Also, they can use up (all available) memory causing your system to be slow, to hang or even bringing the system to a halt. They can also destroy files within your system.

Although some of the symptoms listed above can indicate a hardware or software problem, you should still use your updated antivirus software to scan your computer fully, no one can tell..

We all need to take steps to make sure that our computers are safe or we risk infection.

Combating Viruses, Worms and Trojan Horses

Here are some of the ways to keep your system free of Viruses.

1. Install and Run an Anti-Virus Program

There are many out there. Download and install the package of your choice now before you forget.

2. Update the Anti-Virus Database

Your first step should be to update the virus signature database that came with the installation. An Anti-Virus is only as good as the frequency with which it is updated. New viruses, worms, and Trojan horses are being created, born 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. To learn how to enable or configure your anti-virus software to update automatically, click here

     

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