Validating PowerShell PSCredential - security

Question

Let's say I have a PSCrendential object in PowerShell that I created using Get-Credential.
How can I validate the input against Active Directory ?
By now I found this way, but I feel it's a bit ugly :
[void][System.Reflection.Assembly]::LoadWithPartialName("System.DirectoryServices.AccountManagement")
function Validate-Credentials([System.Management.Automation.PSCredential]$credentials)
{
$pctx = New-Object System.DirectoryServices.AccountManagement.PrincipalContext([System.DirectoryServices.AccountManagement.ContextType]::Domain, "domain")
$nc = $credentials.GetNetworkCredential()
return $pctx.ValidateCredentials($nc.UserName, $nc.Password)
}
$credentials = Get-Credential
Validate-Credentials $credentials
[Edit, two years later] For future readers, please note that Test-Credential or Test-PSCredential are better names, because Validate is not a valid powershell verb (see Get-Verb)

Answer 1

I believe using System.DirectoryServices.AccountManagement is the less ugly way:
This is using ADSI (more ugly?):
$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"
}

Answer 2

I was having a similar issue with an installer and required to verify the service account details supplied. I wanted to avoid using the AD module in Powershell as I wasn't 100% this would be installed on the machine running the script.
I did the test using the below, it is slightly dirty but it does work.
try{
start-process -Credential $c -FilePath ping -WindowStyle Hidden
} catch {
write-error $_.Exception.Message
break
}