Verify active directory user and password

Add-Type -AssemblyName System.DirectoryServices.AccountManagement

$context = [System.DirectoryServices.AccountManagement.ContextType]::Domain

$principalc = New-Object System.DirectoryServices.AccountManagement.PrincipalContext($context, 'local.intra', 'testuser','pass')

$principalc.ConnectedServer

$principalc.ValidateCredentials('testuser','pass')