[Crypt]

What kind of VPS are you talking about? Windows or Linux? For windows the default name is either admin or administrator and for linux I'm pretty sure it's root. Before trying to bruteforce a windows vps you should see if it's unpatched or not, there's a samba exploit in metasploit that can be used to hack and gain full access to the system but I'm not going to explain all of that, look it up if you wish to know what it is.