Anti-virus Software

Anti-virus software protects your computer from getting infected by computer viruses and keeps your computer from infecting others. Anti-virus software is considered the first line of defense against attacks. Without it, you face a high risk of being infected with a virus. Some of the most popular brands are Norton Antivirus , Trend Micro  and McAfee . There are free anti-virus applications available also, such as AVG , and some large vendors (e.g., Trend Micro) offer free online virus scans.

1. Those that examine files that enter, leave, or are edited on your computer. This type of anti-virus software compares your files to files with known virus patterns. This software normally has two parts: (1) an engine that scans the files and performs the comparisons; and (2) a file containing all known virus patterns that is provided by the manufacturer. This file is constantly updated with new virus patterns, so it is important to keep your anti-virus software updated.
2. Those that monitor the behavior of your computer. This anti-virus software looks for behaviors that match typical virus symptoms (e.g., the computer is too slow, it freezes often, or new garbage files appear on the desktop). As with the other type of antivirus software, this software usually has an engine and a pattern file. The engine is in charge of monitoring behaviors, and the pattern file contains a list of symptoms of new viruses. This software must also be updated frequently.

Given that anti-virus software works by comparisons, anti-virus software engineers are constantly scrambling to update virus patterns for new viruses. Developing the pattern and remedy for a new virus typically takes at least a couple of days, which introduces a “window of vulnerability” between when a virus is released and when an antidote and pattern are released. During that period of time, you can get infected even if you have anti-virus software.

Due to this window of vulnerability, anti-virus applications are also used for curing infections. Whenever the application detects a virus, it will usually try to eliminate it. Curing your computer can mean three things:

1. Cleaning the malicious part of the file.
2. Sending the infected file to quarantine, i.e., a special place on your computer where it can’t do any harm.
3. If 1 and 2 fail, deleting the file.

The order in which these actions take place is very important. Most vendors allow you to configure the order of these actions, but we recommend that you perform them in the order listed.