Spyware deluge hits 55 million milestone

Spyware - and its sibling adware - now appears on a significant portion of PCs.

During the first half of 2004, ISP EarthLink and Webroot Software scanned two million consumer systems only to find 55 million instances of spyware.

The more systems scanned each month, the more spyware was found, with the average instances of spyware found per scan staying consistent at about 26 per cent.

The vast majority of malicious programmes - about 78 per cent - were identified as adware cookies. Cookies are files stored on your computer when you visit websites. The adware variety generally contains personal information such as your username and password which is shared with other sites that want to target ads.

Adware itself was the second most common form of spyware, making up 20 per cent of the total. System monitoring programme and Trojan horses accounted for roughly equal portions of the remaining two per cent.

Though adware is generally used to serve pop-up ads, the companies warn that it's not always harmless.

One such programme, called CoolWebSearch, can crash systems by launching several pop-up ads at once, alter browser settings, add websites to your favourites list or dump large files on your hard drive.

The Webroot-EarthLink scans revealed over 100 variations of this pest.

Your best defence, the companies say, is to employ anti-spyware programmes on your machine.