Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Friday, January 28, 2011

How to find out which clients in your domain were added by an Authenticated User

In a Windows domain, all Authenticated Users have the ability to add up to 10 clients to the domain without contacting a Domain Admin. Here is how to find out which computers were added to your domain by your users.

On the Windows Server 2008 R2 Domain Controller, open PowerShell

Type Import-Module ActiveDirectory and press Enter

Type get-ADComputer –filter * –property ms-DS-CreatorSID where {‘$_.ms-DS-CreatorSID’ –like ‘*’} and press Enter.

Each computer that is listed has a value in the ms-DS-CreatorSID attribute. If the computer account was pre-created in Active Directory Users and Computers or manually joined by a Domain Administrator, a SID would not be present here. The SID is the SID of the user account that joined the computer to the domain.

OK, that was informative. You may be asking “How do I find out who added what?” The answer is in PowerShell. Sure, you could manually search each Computer account in Active Directory and record any ms-DS-CreatorSID attributes that you find. You could then manually look at the SID for each user and compare them. I would not waste my time that way. Here is a script that will do it for you. This is a PowerShell V2 script. Do not forget to run Import-Module ActiveDirectory into the PowerShell ISE before running this.


$CompList = Get-AdComputer –filter * –property ms-DS-CreatorSID | Select name, ms-DS-CreatorSID
$UserAccounts = Get-ADUser –Filter *
ForEach ($Comp in $CompList) {
ForEach ($User in $UserAccounts) {
$Test = $User.SID.Value
If ($Comp –like ‘*’ + $Test + ‘*’) {
Write-Host $User.Name Created $Comp.Name
}
}
}

The first line enumerates all the computer accounts in Active Directory. It includes the property ms-DC-CreatorSID since this attribute is not normally returned in this query. The data is the piped to the Select cmdlet so only the name and the SID is left.

Line 2 Enumerates all the user accounts in Active Directory and stores all the objectys in the variable $UserAccounts.

Line 3 cycles through each record from line 1 and examines them one at a time.

Line 4 cycles through each record of user accounts one at a time.

Line 5 creates a variable called $Test. This variable holds the value of the SID for the User account that is currently being examined.

Line 6 Compares the SID recovered from the creator of the computer account, and the users SID. The data from the computer account has some extra data in it. for that reason, we used wild card characters around the $Test variable so this extra data will not be of concern.

Line 7 writes who installed what to the display.
The remaining lines are syntax for closing the ForEach loops.

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