More than 10,000 web pages have been booby trapped with malware in one of the largest attacks of its kind to date.
Miscreants likely reprogrammed the web pages after scanning the net for insecure servers.
The malware cocktail attempts to exploit vulnerabilities in Windows, RealPlayer, and other applications to break into insecure PCs, according to an analysis by net security firm McAfee.
Components of the malware attempt to steal passwords to online games while others leave a back door that allows the installation of additional malicious programs.
McAfee Avert Labs first spotted this attack on Wednesday, 12 March. Of the 10,000 pages that were compromised, a number have already been cleaned up.
A single organisation or small group is likely behind this attack, as the malicious code on all these pages is served up from the same server in China.
Craig Schmugar, threat researcher at McAfee Avert Labs, said the attack illustrated that the conventional wisdom that surfers are safe providing they stick to trusted sites (and away from warez and porn) no longer holds true.
"Often you hear warnings about not going to untrusted sites," said Schmugar. "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." ®