Run a root check:
To install chrootkit, SSH into server and login as root.
At command prompt type: cd /root/
At command prompt type: wget
ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.tar.gz
At command prompt type: tar xvzf chkrootkit.tar.gz
At command prompt type: cd chkrootkit-0.47
At command prompt type: make sense
To run chkrootkit
At command prompt type: /root/chkrootkit-0.47/chkrootkit
If you clean then remove the account on the server and start it over. Any page can be a back door so really you should start it over.