Week Four--Chapters Three and Four

Question 1: What is a computer virus and how is it transmitted? What can you do to protect your computer?

Our book describes a computer virus as “a program written specifically to disrupt computer operations and/or destroy data.” As this definition points out, viruses do not just pop into existence from nowhere! They are maliciously created by programmers. Some of them, like “spyware,” are created for the intention of obtaining information about people and their actions from their computers and sending it to the creator. Other viruses are purely disruptive in their actions. Some can simply delete random items from an infected hard drive. A virus might have a directive to launch a DOS (denial of service) attack on a particular website, data center, corporation, or government agency. This type of attack is designed to overwhelm its target by sending many requests that the server cannot fulfill thus rendering the target unable to be productive.
Viruses can be transmitted in many different ways. The increasing connectedness of todays computers yields many routes of infection. People often unwittingly download viruses from the internet when trying to download files or checking their email. Viruses can be sent as attachments that appear to be benign files, and novice users will often open these files without checking them first. These viruses could perform their intended action immediately, but they could also just copy themselves to the hard drive and wait for a predetermined time, or even a signal from their creator to start their mischief. Computers not connected to the internet can get viruses by introducing infected media (floppies, CDs, thumb-drives). In a school environment it is particularly hard to prevent since students could bring media from home containing infected material. Once the virus has been introduced it can easily propagate throughout the network.

There is defense against viruses! Many companies sell antivirus software. This software scans files on a system and monitors media connected as well as traffic coming in through the network. When antivirus software detects a known threat it can isolate the file and ask the user what should be done with it. An extra layer of protection is often helpful when dealing with email. Many email providers, including many webmail providers like Gmail, provide virus scanning before you even open your email.

Any antivirus software is only as good as it’s “definitions.” As new viruses are created the antivirus software creators catalog them and provide downloads to their customers that instruct the antivirus software what to look for. These updates to definitions must be done regularly to ensure the best protection. In the modern world of computing it is considered irresponsible to not have antivirus software running on your computer, but even when it is present one should always be looking out for malicious applications.