If you’ve found your PC running slowly or causing you no end of problems after visiting a website that didn’t quite look as legitimate as you expected it to, then it’s likely that you have been the victim of a “drive-by download”.
The term ‘drive-by download’ has a number of definitions but is, in principle, the process where malicious software is downloaded to your PC without your consent or knowledge. This is most commonly due to visiting an infected website, opening a seemingly legitimate email attachment or installing an unknown browser Plugin.
Regardless of how you come across a drive-by download, they almost exclusively work by exploiting a vulnerability in your browser. For that reason, it is essential to ensure that you regularly update your browser as well as your antivirus software. Other browsers, such as Google Chrome or Mozilla Firefox, sell themselves on the claim that they are less susceptible to such attacks than Microsoft’s Internet Explorer.
But this form of attack has come a long way since the days of the pop-up ad explaining how to claim your free laptop or inviting you to play a duck shooting game and it is something of a fallacy that the only sites where malware resides are suspicious looking URL’s from notorious virus hot spots -far from it. In recent years, malware distributors are increasingly looking to exploit weaknesses in web and ad servers in many of the world’s respected websites. In September 2009, ads on the New York Times website were infected with malicious software whilst the website of the Daily Mail has also been the target of a similar attack.
The advice to computer users is simply to make sure that your antivirus software is installed and up to date and that they also install the latest security updates and bulletins for your browser software. Also consider using a firewall, a system that prevents unauthorised traffic from entering and leaving your PC, which can be found in most antivirus software packages.