If a new computer virus, unknown to your anti-virus software, starts spreading on the internet and you are unlucky enough to infect your computer with this new virus, your antivirus software will not be able to identify and protect you against it. This new virus can infect millions of computers around the world and cause billions of dollars of damages before it is detected by any of the antivirus software makers. So, it is important for the antivirus software makers to monitor the internet closely and frequently to detect any new threats as quickly as possible.
After a virus is found, a signature is created and tested, which is then used to identify the virus or any family of that virus. The antivirus software makers will then make the new virus signature available for download for your antivirus software via the internet. Once your antivirus software downloads this new signature it will be able to detect and remove that new virus. This is why it is important that your antivirus software updates itself frequently via the internet.
The virus detection method that I have mentioned above is called the “Dictionary Approach” and is the most popular and effective way of detecting known computer viruses. There is another method called “Heuristic Analysis” which can be used to detect new unknown computer viruses but is not 100% accurate. It may generate false alarms or false positives because its detection is based on behavioral patterns, various decision rules or weighing methods, therefore, it will not detect all new unknown viruses.
Having an antivirus software installed on your computer doesn’t mean that you should browse the internet recklessly. You should still exercise caution when downloading files from the internet and opening email attachments. Ensure that you are downloading files from trusted sources, browsing trusted websites and opening only expected email attachments.
Antivirus software is still very important because they protect you from the thousands of viruses and malicious programs that have already been discovered. But, do not think that you are 100% safe with one installed on your computer.