Powershell
From Wildsong
Test a login
Grabbed from https://serverfault.com/questions/410240/is-there-a-windows-command-line-utility-to-verify-user-credentials
Create a function in PS
Function Test-ADAuthentication { param($username,$password) (new-object directoryservices.directoryentry "",$username,$password).psbase.name -ne $null }
Apply it
Test-AdAuthentication "MYDOMAIN\brian" "password123" True