i dont think its a wordpress issue, because all my index.php files were only writable by the owner, so it couldnt been done via script, only from the server, and also not wordpress websites got it too... on my account my websites are clean, i didnt got the code again, it must be cause by the cluster...

i had problems recently with servage with exploit Iframe trojan found on my websites : here i wrote about it on my blog
http://www.proxyutza.com/2008/03/07/exp ... infection/