Parsing Active Directory Groups

In a previous post we shared a PowerShell script that would allow an auditor to parse a list of groups and group members on a Microsoft Windows system as a part of a security assessment or baselining process. The question has come up though – what if someone wants to follow the same process but parse a list of Active Directory groups and their members instead?

It turns out that it is much easier to perform the task against Active Directory than it is to do it against a local Microsoft Windows local Security Accounts Manager (SAM) database. It seems that the native capabilities of the Active Directory PowerShell cmdlets is going to make it easier for us to accomplish this task.

The output requirement for this script will be the same as for the previous. The output should be in a CSV format that could be easily parsed by a spreadsheet program like Microsoft Excel. Also, like the previous script, empty groups should still be listed, but just without any group members listed along with them.

The code we used to parse a list of AD groups and their members is:

Get-ADGroup -Filter * | ForEach-Object { 
    $GroupName = $_.Name 
    $Members = Get-ADGroupMember $_.samaccountname -Recursive | foreach{$_.Name} 
        If ($Members.count -ge 1){
            $Out = $GroupName + "," + [String]::Join(",", $Members)
            $out | Out-File -append ad_group_members.txt
        }
        Else{
            $Out = $GroupName
            $out | Out-File -append ad_group_members.txt  
        }
    } 

Ideally an auditor would combine this script with our previous example and using PowerShell remoting run one script that would parse local and Active Directory groups at the same time and output the data as an easily readable file. But between the two examples, hopefully it will give you enough inspiration to make this usable for you in your audit efforts.