Microsoft has yet to still patch a security hole in Windows related to an animated cursor that hackers could use to launch attacks on websites.

Microsoft has said that it will release a security patch today, outside of its regular monthly security update, which typically falls on the second Tuesday of each month because it has completed testing earlier than anticipated.

According to Security firm F-Secure, over the weekend the amount of attacks using this exploit intensified with the majority of the attacks being traced back to different Chinese hacker groups.

"This vulnerability is really tempting for the bad guys", said Mikko Hypponen, chief research officer at F-Secure. "It's easy to modify the exploit, and it can be launched via Web or e-mail fairly easily."

According to the company, most of the activity around the ANI exploit has been via dozens of malicious websites that will attack the user if he visits the page with the most common versions of Microsoft's Internet Explorer. However, on Sunday the first worm using this exploit to spread was found.

F-Secure says its security products detect and block the known versions of the ANI exploits and worms.