Tag Archives: Get-ADGroup

Active Directory Friday: Find groups with no members

Occasionally groups may become obsolete or are never populated with members. It can be interesting to find out how many groups are in your organization that have no members, as action can be taken on it based on the output.

Overview of articles in this series
Active Directory Friday: Find groups with no members
Active Directory Friday: Principal group membership
Active Directory Friday: User account group membership

Because of the nature of how group membership is defined this article will be the first in a series of three. In this article I will show how group membership can be determined using an LDAP queries. The next article in this series will go into principal group membership and its implications and the final article will go into constructed attributes and how to work with constructed attributes, specifically the memberof attribute.

In this article I will give a a number of examples that can be used to determine which groups are empty. Using Get-ADGroup the following command can be executed to retrieve memberless groups:

Get-ADGroup -LDAPFilter '(!(member=*))'

Get-ADGroupNotMemberAnything

Alternatively the DirectoryServices.DirectorySearcher object can be used to achieve a similar result:

(New-Object DirectoryServices.DirectorySearcher -Property @{
 Filter = '(&(objectClass=group)(!(member=*)))'
 PageSize = 100
}).FindAll()

The [adsisearcher] type accelerator is another interesting alternative for this purpose, here is an example:

([adsisearcher]'(&(objectClass=group)(!(member=*)))').FindAll()

The problem with the above examples however, is that some groups will show up as being empty, for example the Domain Users group. Next week I will go into Principal group membership, what this is and how to query for this and by doing so generate more accurate results in regards to group membership.

For more information about the topics discussed in this article, please have a look at the following resources:

Active Directory Friday: Find groups with no members
Get-ADGroup
JaapBrasser.com – Active Directory Friday
Free ebook – Active Directory Friday All Articles
DirectoryServices.DirectorySearcher
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Active Directory Friday: Distribution group membership for AD User

To get a list of distribution groups an Active Directory user account is a member of of we can query Active Directory. For example by combining the Get-ADUser and Get-ADGroup cmdlets. To generate this list the following code can be used:

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Get-ADUser -Identity JaapBrasser -property memberof |
Select-Object -ExpandProperty memberof | Get-ADGroup |
Where-Object {$_.groupcategory -eq 'Distribution'}

The Get-ADUser cmdlet gets all the groups Jaap Brasser is a member of, the Select-Object cmdlet expands the MemberOf attribute which is then piped into the Get-ADGroup cmdlet. The last step is using the Where-Object cmdlet to filter out only the Distribution groups to get the desired results.

Alternatively the DirectoryServices DirectorySearcher object can be used. This object does not require the Active Directory module to be installed and can run on any version of PowerShell. The following code can be used:

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$ADSearcher = New-Object DirectoryServices.DirectorySearcher -Property @{
    Filter = "(samaccountname=JaapBrasser)"
} | ForEach-Object {
    $_.FindOne().Properties.memberof | ForEach-Object {
        $CurrentGroup = [adsi]"LDAP://$_"
        if (-not ([int](-join $CurrentGroup.Properties.grouptype) -band 0x80000000)) {
            $CurrentGroup.Properties.name
        }
    }
}

This sample works by querying Active Directory for the samaccountname JaapBrasser. Of this user account the distinguishedname of each group object is retrieved. The group type is explained in last weeks post as well, in which I explained about the hex codes which defines whether a group is a Security Group or a Distribution group. The article is available here: Creating Active Directory groups using PowerShell

For more information on this subject please refer to the following links:

Distribution group membership
Get-ADGroup
Get-ADUser
Understanding Groups
2.2.12 Group Type Flags
Creating Active Directory groups using PowerShell
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