VIRUS: Definition, Prevention and Removal

DEFINITION

Although the term "virus" is used as a catch-all to describe any type of software threat found on a computer, the truth is a virus is a specific type of program with characteristics that make it different from other kinds of threats. Specifically, there are three such characteristics: reproduction ability, mode of attack, and means of transmission.

A computer virus is an executable program which is able to make copies of itself and spread throughout the infected machine. Competent hackers can develop viruses which upon first execution, make a copy of themselves and hide it in a place that insures its continued reproduction. Frequently a virus will be programmed to write to a computer's boot sector, insuring that it is executed every time the machine is booted.

Once the virus compromises a computer and begins to copy itself, the mode of attack is for the virus to attach itself to specific files, either corrupting the data or destroying them completely. Microsoft Office for example, has been a big target since the 1990s due to its widespread use across the globe. Viruses have been written which attach themselves to Office documents, destroying data and attaching themselves to address books and emails. While most viruses used to be nothing more than jokes or amusements, they have become increasingly more malicious and destructive through the years.

Viruses depend on a host program for their transmission to other computers. In one scenario, a virus author may attach his program to a piece of free software made available on the internet. A user will download the program and run the installation, inadvertently executing the virus in the background. Viruses can also be spread via USB flash drives, CD-ROMs, iPods, or any other physical device that can be attached to a computer for data transfer.

PREVENTION

The first and most common step in virus protection is a standard anti-virus software package. Different packages offer varying degrees of protection, but as a general rule you get what you pay for. Regardless of the anti-virus program you use, it should always remain updated and running. Configure the settings to allow automatic updates at least every day and to run at system start-up. Most programs will run and update in the background with little interference to the user. Additionally, run periodic system scans; once per week is sufficient in most cases.

There are more prevention steps that can be taken, beginning with never downloading software unless you are absolutely sure it is from a safe source. Warez and file sharing sites are notorious for being virus carriers. Next, turn off your computer when not in use. If you use broadband internet service you are connected to the internet whenever your computer is running, making it a potential target for threats. Finally, do not open email attachments unless you have made prior arrangements with the sender, or you ask them about it prior to opening. Email attachments are the biggest single source of virus attacks.

REMOVAL

While computer viruses are easily executed and spread, they are equally easy to get rid of. Executable programs leave a long trail of activity on the infected machine, making it easy for anti-virus developers to write removal tools. In most cases one can be produced within hours of the first outbreak, although sometimes it takes a little longer.

If a system scan detects a virus, have the program fix, delete, or quarantine the affected files. Next, check the website of your anti-virus vendor for a removal tool for that specific virus (your anti-virus software should tell you the name). If a removal tool is available, download and run it. If not, you may have to employ the services of a professional to remove it from your system manually. If you are an advanced user comfortable with the system registry, you may be able to follow instructions supplied by your software vendor to do this yourself. Use extreme caution if you decide to undertake manual removal on your own.