Computer security company McAfee has warned that thousands of well known websites have been corrupted to redirect users onto pages laden with software that could compromise their PC and steal the passwords to online games.

McAfee has already identified 10,000 webpages which send unsuspecting surfers onto other sites that could potentially infect their computer with malware and allow the hijacking of their PC. The company produces one of the most popular anti-virus software packages.

It added that the piece of software that is often installed is designed to steal passwords to ‘online games’.

Trusted sites?

"Often you hear warnings about not going to un-trusted sites," said Craig Schmugar, threat researcher at McAfee Avert Labs. "That is good advice, but it is not enough. Even sites you know can become compromised.

"You went to a place before that you trust, but that trust was violated through a vulnerability that was exploited."

McAfee claims that unprotected servers allow teams of cyber-criminals to plant javascript on pages which then redirects to special trap pages.

The user can often be completely unaware that their computer has been compromised, allowing their machine to be used in vast bot-nets of computers that can be used in cyber-crime, spam mailing and distributed denial of service (DoS) attacks that bombard certain sites with so much traffic that they cannot cope and break.