Invoke-command doesn't need credentials - powershell

Question

I have 2 servers (windows server 2012 R2) in the same domain.
I execute a command on server01:
Invoke-Command -ComputerName server02 -Credential Administrator -ScriptBlock {Get-Culture}
I give the password of my Administrator (of server2) and it works well.
But when I try:
Invoke-Command -ComputerName server02 -ScriptBlock {Get-Culture}
It also seems to work. Probably because the 2 servers are in the same domain. While I only want it to work when you can provide the right credentials. Can someone help me with it?

Answer 1

You are probably doing this by Domain Admin account or account that it's in Domain Admins group or so.
In any case this results because your account has privelegies on that computer.

Answer 2

With which user do you execute the script on server01? Does that user have permissions on server02 too? If your user has admin permission on server01 and server02 then no credentials are neccessary... (as far as I know)
To check if the provided credentials are valid have a look here:
https://gallery.technet.microsoft.com/scriptcenter/Test-Credential-dda902c6
Or something like this:
$cred = Get-Credential #Read credentials
$username = $cred.username
$password = $cred.GetNetworkCredential().password
# Get current domain using logged-on user's credentials
$CurrentDomain = "LDAP://" + ([ADSI]"").distinguishedName
$domain = New-Object System.DirectoryServices.DirectoryEntry($CurrentDomain,$UserName,$Password)
if ($domain.name -eq $null)
{
write-host "Authentication failed - please verify your username and password."
exit #terminate the script.
}
else
{
write-host "Successfully authenticated with domain $domain.name"
}
Which was found here (but I haven't tested it):
https://serverfault.com/questions/276098/check-if-user-password-input-is-valid-in-powershell-script