A cartoon that ridicules the efforts of a Chinese gymnast at the Olympic games is the latest ploy used by cybercriminals to infect Windows PCs, according to McAfee Avert labs.

While the movie files, which show the cartoon followed by images supporting a free Tibet, are playing, a keystroke-logging tool, hidden by a rootkit, is installed on to the user's PC.

McAfee Researcher, Patrick Comiotto, said: "This is a pro-Tibet Rootkit. What looks like a simple Flash movie actually silently drops a number of files onto your PC and then hides those files."

This is second Olympics-related virus in seven days. The 'Fribet' Trojan horse was placed on hacked websites and subsequently loaded on to the PCs through a Windows vulnerability.

Dave Marcus, security research and communications manager at McAfee Avert Labs, said: "Cybercrooks are increasingly taking advantage of the high general interest in the Olympic Games to trick people into giving up personal information or to load malware onto their PCs. If you want to watch the Olympic Games it's better not to do it by opening a file that appears to be a movie that comes in email."