# PowerShell function to list users in Authoritative Groups in Active Directory
# http://jeffwouters.nl/index.php/2013/11/powershell-function-to-list-users-in-authorative-groups-in-active-directory/

# Import the Modules
Import-Module ActiveDirectory

function Get-ElevatedUsers {
    $GroupType = '-2147483643'
    # A group type of -2147483643 specifies all groups with a domain local scope created by the system.
    # References:
    # - http://msdn.microsoft.com/en-us/library/windows/desktop/ms675935(v=vs.85).aspx
    # - http://blogs.technet.com/b/heyscriptingguy/archive/2004/12/21/how-can-i-tell-whether-a-group-is-a-security-group-or-a-distribution-group.aspx
    $ElevatedGroups = Get-ADGroup -Filter { grouptype -eq $GroupType } -Properties members
    $Elevatedgroups = $ElevatedGroups | Where-Object { ($_.Name -ne 'Guests') -and ($_.Name -ne 'Users') }
    foreach ($ElevatedGroup in $ElevatedGroups) {
        $Members = $ElevatedGroup | Select-Object -ExpandProperty members
        foreach ($Member in $Members) {
            $Status = $true
            try {
                $MemberIsUser = Get-ADUser $Member -ErrorAction silentlycontinue
            }
            catch { $Status = $false }
            if ($Status -eq $true) {
                $Object = New-Object -TypeName PSObject
                $Object | Add-Member -MemberType noteproperty -Name 'Group' -Value $ElevatedGroup.Name
                $Object | Add-Member -MemberType noteproperty -name 'User' -Value $MemberIsUser.Name
                $Object
            }
            else {
                $Status = $true
                try {
                    $GroupMembers = Get-ADGroup $Member -ErrorAction silentlycontinue | Get-ADGroupMember -Recursive -ErrorAction silentlycontinue
                }
                catch { $Status = $false }
                if ($Status -eq $true) {
                    foreach ($GroupMember in $GroupMembers) {
                        $Object = New-Object -TypeName PSObject
                        $Object | Add-Member -MemberType noteproperty -Name 'Group' -Value $ElevatedGroup.Name
                        $Object | Add-Member -MemberType noteproperty -Name 'User' -Value $GroupMember.Name
                        $Object
                    }
                }
            }
        }
    }
}

Get-ElevatedUsers