Verify Active Directory credentials

Test-ADCredential.ps1

function Test-ADCredential {
<#
.Synopsis
    Verify Active Directory credentials
.EXAMPLE
    Test-ADCredential -Username user1 -Password Secret01
#>

[CmdletBinding(DefaultParameterSetName = 'PSCreds')]
[OutputType([Boolean])]
Param (
    [Parameter(Mandatory=$true,Position=0,ParameterSetName = 'PlainText')]
    [string]$Username,
    [Parameter(Mandatory=$true,Position=1,ParameterSetName = 'PlainText')]
    [string]$Password,

    [Parameter(Mandatory=$true,Position=0,ParameterSetName = 'PSCreds')]
    [pscredential]$Credential,

    [validateset('Domain','Machine','ApplicationDirectory')]  # AppDirectory is for ADAM
    [string]$Context = 'Domain',

    [switch]$DontCheckProfile
)

# get the user/pass from the pscreds
if ($PSCmdlet.ParameterSetName -eq 'PSCreds') {
    $Username = $Credential.UserName
    $Password = $Credential.GetNetworkCredential().Password
}

# strip the domain prefix from the username
if ($Username.IndexOf('\') -ge 1) {$Username = $Username.Split('\')[1]}

# see if the user's profile already exists in the system
if (-not $DontCheckProfile) {
    # find the Security ID (SID) of the user    
    try {
        $NtAccount = [Security.Principal.NTAccount]::new($env:USERDOMAIN, $Username)
        $UserSID   = $NtAccount.Translate([Security.Principal.SecurityIdentifier]).Value
    }
    catch {
        Write-Warning "Could not find user $Username in $env:USERDOMAIN"
        return
    }

    # load the CimCmdlets module
    if ((Get-Module).Name -notcontains 'CimCmdlets') {Import-Module -Name CimCmdlets -Verbose:$false}

    # get the local user profile
    $UserProfile = Get-CimInstance -ClassName Win32_UserProfile -Filter "SID = '$UserSID'" -Verbose:$false
    
    # inform the user that the profile will be created
    if ($null -eq $UserProfile) {
        Write-Verbose "The user $Username does not have a profile on this computer ($env:COMPUTERNAME)"
        Write-Verbose 'The credential check will take a bit longer, because the user profile will also be created for the 1st time.'
    }
}

# load the .net type for DirectoryServices
if (-not ('System.DirectoryServices.AccountManagement.ContextType' -as [type])) {
    Add-Type -AssemblyName System.DirectoryServices.AccountManagement -ErrorAction Stop
}

# finally check the account
$CtxType   = [System.DirectoryServices.AccountManagement.ContextType]::$Context
$Principal = [System.DirectoryServices.AccountManagement.PrincipalContext]::new($CtxType)
$CanLogin  = $Principal.ValidateCredentials($Username, $Password)

# clean up
$Principal.Dispose()

# show the output
Write-Output $CanLogin  # <-- boolean
}