More than 1 million computers are infected by hackers

Websense computer security company on April 1 warned that hackers have made more than 1 million websites infected with malicious code to trick Internet users.

These legitimate sites are "trapped" to redirect visitors to addresses where they are greeted with fake warnings that their computers have been compromised.

This trick is designed to scare users into causing them to download and install fake antivirus software, described as Windows Security Center.

Those who are trapped, may even pay to download, are actually installing malware for the purpose of hackers.

Experts say this is the biggest attack of this kind ever. Websense said hackers insert malicious code into web pages by accessing servers running the databases behind the Internet.

According to Websense senior officials, the attack has so far affected most small websites, but there is no evidence that large corporate or government websites have been compromised.