orentraff.cn hacker?

Hi people..

When i navigate trough my sites i see a unknown address appearing for a fraction of a second,it mostly appears when i use the back & forward buttons in my browserwindow.



I used Google to know more about that orentraff.cn domain and it seems it is a domains that's hosted in China and that it is some kind of hacker.
But no idea what this hack (if it is a hack) does.
I can't find any damage or alterations that was done to my sites.
Anyone else that experienced this problem?


This is what i found using Google:

"orentraff.cn is a domain name. The code was calling something from
another server into an invisible iframe. That something is probably
malicious."