Find users in too many groups

Large Kerberos tokens (caused by too many groups listed in them) can be an issue in some environments (I’ve just had a similar trouble myself in an ADFS deployment). Luckily PowerShell is here to help. This quick script will list all users who are members of more than 75 groups:

$limit = 75
Get-QADUser -SizeLimit 0 -DontUseDefaultIncludedProperties |
  ForEach-Object {
    $groups = Get-QADGroup -ContainsIndirectMember $_.DN -SizeLimit $limit `
      -DontUseDefaultIncludedProperties -WarningAction SilentlyContinue
    if ($groups.Count -ge $limit) { $_ }
  }

Here’s a quick overview of what the script is doing:

1. I assign the limit (75) to a variable. This is just for my convenience of reuse. E.g. I could turn this line into param($limit = 75) – and save this as a parameterized script or turn it into a function.
2. I user Get-QADUser to retrieve all (-SizeLimit 0) user accounts from my current domain and I make sure to not retrieve any attributes along – so I save memory and improve performance (-DontUseDefaultIncludedProperties)
3. For each user in my domain, I retrieve the first 75 (-SizeLimit $limit) groups to which the user belongs directly or through nesting (-ContainsIndirectMember $_.DN). There’s obviously no need to retrieve all groups – we just need to know if the user reached the limit. Again, we do not need any attributes (-DontUseDefaultIncludedProperties). I also tell PowerShell to not warn me if there are more groups than the size limit I specified (-WarningAction SilentlyContinue).
4. Finally, if indeed we reached the limit, I output that user object.

You can obviously then just see the list on the screen or output it to CSV or HTML report.

Tags: AD, AD cmdlets, Active Directory, Examples, PowerShell, cmdlets, one-liner, oneliner
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