Fix Protected Users check

Uploaded a renamed, working Protected Users check.

The rename aligns the PS1 filename with the function name.
I fixed a gap in the SID matching and also added a check for primaryGroupID (525).

The function is maintained at https://github.com/samerde/active-directory.

Private/Test-IsMemberOfProtectedUsers.ps1

@@ -0,0 +1,72 @@
+function Test-IsMemberOfProtectedUsers {
+    <#
+        .SYNOPSIS
+            Check to see if a user is a member of the Protected Users group.
+
+        .DESCRIPTION
+            This function checks to see if a specified user or the current user is a member of the Protected Users group in AD.
+            It also checked the user's primary group ID in case that is set to 525 (Protected Users).
+
+        .PARAMETER User
+            The user that will be checked for membership in the Protected Users group. This parameter accepts input from the pipeline.
+
+        .EXAMPLE
+            This example will check if JaneDoe is a member of the Protected Users group.
+
+            Test-IsMemberOfProtectedUsers -User JaneDoe
+
+        .EXAMPLE
+            This example will check if the current user is a member of the Protected Users group.
+
+            Test-IsMemberOfProtectedUsers
+
+        .INPUTS
+            Active Directory user object, user SID, SamAccountName, etc
+
+        .OUTPUTS
+            True, False
+    #>
+
+    [CmdletBinding()]
+    param (
+        # User parameter accepts any input that is valid for Get-ADUser
+        [Parameter(
+            ValueFromPipeline = $true
+        )]
+        $User
+    )
+
+    Import-Module ActiveDirectory
+
+    # Use the currently logged in user if none is specified
+    # Get the user from Active Directory
+    if (-not($User)) {
+        # These two are different types. Fixed by referencing $CheckUser.SID later, but should fix here by using one type.
+        $CurrentUser = ([System.Security.Principal.WindowsIdentity]::GetCurrent().Name).Split('\')[-1]
+        $CheckUser = Get-ADUser $CurrentUser -Properties primaryGroupID
+    }
+    else {
+        $CheckUser = Get-ADUser $User -Properties primaryGroupID
+    }
+
+    # Get the Protected Users group by SID instead of by its name to ensure compatibility with any locale or language.
+    $DomainSID = (Get-ADDomain).DomainSID.Value
+    $ProtectedUsersSID = "$DomainSID-525"
+
+    # Get members of the Protected Users group for the current domain. Recuse in case groups are nested in it.
+    $ProtectedUsers = Get-ADGroupMember -Identity $ProtectedUsersSID -Recursive | Select-Object -Unique
+
+    # Check if the current user is in the 'Protected Users' group
+    if ($ProtectedUsers.SID.Value -contains $CheckUser.SID) {
+        Write-Verbose "$($CheckUser.Name) ($($CheckUser.DistinguishedName)) is a member of the Protected Users group."
+        $true
+    } else {
+        # Check if the user's PGID (primary group ID) is set to the Protected Users group RID (525).
+        if ( $CheckUser.primaryGroupID -eq '525' ) {
+            $true
+        } else {
+            Write-Verbose "$($CheckUser.Name) ($($CheckUser.DistinguishedName)) is not a member of the Protected Users group."
+            $false
+        }
+    }
+}