Tool Factory: Release of PS-REPADMIN 1.9

PS-REPADMIN 1.9 is available now. PS-REPADMIN helps to view object metadata and attribute values in a simple table view.
We made several improvements in 1.9, especially for comparing groups with their metadata between trusted Active Directory domains. The tool also provides now an easier look on Proxy Addresses and Linked Attribute values.

PS-REPADMIN 1.9 was tested with Windows 10, Windows Server 2012 R2 and Windows Server 2016. Usage is on own risk. All rights reserved by Silverstar Consulting GmbH.
Download here to test the trial version for free.
(Note: After download, unzip the file and after that rename the .zip extension to .exe)

Full table view on attributes and their last change including group member values. The parallel listing makes it easy to compare values of objects from different domains.

Linked attributes are displayed in a separate view for easier comparison.

Download here to test the trial version for free.
(Note: After download, unzip the file and after that rename the .zip extension to .exe)

Powershell 5 in Windows Management Framework V5 Preview

Microsoft released a Preview of the Windows Management Framework V5. As in the past, this package ships with the according version of Powershell. Powershell V5 will bring interesting new Features.

Among those are:

  1. OneGet module with a set of comandlets to manage Software packages
  2. Commandlets to manage L2 Layer Network Switches

Find the introduction article for Windows Managagement Framework V5 by Jeffrey Snover here on TechNet.

You can dowload the Preview here.

However, the mixture of Powershell Versions we find at customer Environments will get wider and wider. Same is valid for modules like ActiveDirectory or SnapIns for Exchange. One will need to start with a lot of checks in the beginning of the code when a script is planned to be used universally.

How to write or migrate sidHistory with Powershell (3)

In our large scale Active Directory Cross Forest migration project, we now have migrated already 40.000 user accounts globally. Our self made scripting routine to migrate/write sidHistory into the target accounts turned out to be a robust, reliable part of the process and I feel safe now to share some experiences. We are running it on multiple migration servers around the globe as scheduled task – which you can easily call a “service” as it is running every 5 minutes.
I will write about the whole mechanism of how we automated our large scale Active Directory migration in another blog post, but will concentrate here to share our way of managing the sidHistory part.
As you know already from part 2 of this blog post, we were buidling our code on the examples that MSFT Jiri Formacek published here.

However, 2 main restrictions prevented us from using this code as is:

  1. We wanted to make sure that we really used the Domain Controller with the PDC Emulator role from source domain. Our source environment has 100+ domain controllers and the PDC role is siwtched from one DC to another DC under certain conditions. Therefore to use a fixed name for the PDC role Domain Controller was not acceptable.
  2. Our Active Directory account migration process was fully automated and it was the user who starts his/her migration not us. Therefore the requirement was given, that we only can run sidHistory migration (together with the account activation in target domain) as a continuous background service. Every session based approach would not have helped like we can find it in ADMT or Dell Migration Manager for Active Directory.
    Prepopulating sidHistory on the previously created disabled accounts in target domain was not an option, since Exchange 2010 was giving errors for disabled users with sidHistory of source active users under certain circumstances.

Solutions:
1) This was not a big thing. A small function could do the trick.

function getPDCE($domain) {
$context = new-object System.DirectoryServices.ActiveDirectory.DirectoryContext("domain",$domain)
$PDC=[System.DirectoryServices.ActiveDirectory.Domain]::GetDomain($context).PdcRoleOwner.Name
return $PDC
} 

2) This was not that easy (for us). Running our account migration script as usual – means as scheduled task with admin credentials – did not work for the sidHistory part in it since the credentials of the logged user account were not handed over to the SIDCloner routine.
All the code we could find on Jiri’s page asked for credential information interactively or would need explicit credentials in the script in another way.
Although we are packaging our Powershell Scripts into an .exe file by using Sapien Powershell Studio and could hide the password from simple file editing, putting user name and password into the script was not an acceptable way for us to go.
After testing back and forth, someone cam up with the idea of using the Windows credential manager to work around our deadlock situation.
The script would access the credential manager interface, get the credential information from there and would then pass them to the DsAddSidHistory function.
We created a function to retrieve credentials from Credential Manager store based on a very good script example to be found on Technet here.
While this seemed to be a clever way of achieving our target of having a scheduled user account activation script with sidHistory functionality, we ran into errors again. Retrieving credentials from Credential Manager by script obviously fails, when the script runs with exactly the credentials that you want to retrieve. This was true in our case, because the user account migration script was scheduled with that “big admin” account.

The solution finally was:
The user account migration script was running as a scheduled task with full admin credentials. When it came to migrate (in our project setup: activate) a user account in the target domain, it did not (could not) write sidHistory, but created an input file with username and target DC (the DC closest to the site where the user was had logged in from – remember that the user triggers his/her migration in our project).
On the same migration server a second script was scheduled with a server-local admin account. This script consists of 3 parts. First part is to check if there are new input files. Second part is to retrieve the full admin credentials from Credential manager and passing them to second part. Third part is to migrate sidHistory which succeeds because you have put all parts together for the SIDCloner routine:
PDC Emulator DC for source you have found by query.
Target DC was in file (but you can take every writable you want if replication delay does not matter).
Explicit credentials you get from Credential Manager.
Nowhere in both scripts password information is saved in clear text.

Additional Information

How to write or migrate sidHistory with Powershell (2)

SIDCloner.dll
When you look in WWW to find a way to write sidHistory attribute, you probably will stop at the marvelous SID Cloner website created by Jiri Formacek, MSFT (http://code.msdn.microsoft.com/windowsdesktop/SIDCloner-add-sIDHistory-831ae24b). Jiri provides a managed class library that implements the SIDCloner class, which we can use in Powershell and any .NET programming code.
The SID Cloner class is built upon native API to migrate sidHistory and therefore uses the DsAddSidHistory function under the hood (http://msdn.microsoft.com/en-us/library/windows/desktop/ms675918(v=vs.85).aspx).
Although we do not need to install ADMT on any machine to run the SID Cloner code, we still have to consider to meet the same requirements for the migration setup as ADMT does. SID Cloner and ADMT come from the same “mothership” DsAddSidHistory.

SidHistory requirements
In brief we need the following prerequisites to be in place before we can start writing sidHistory (http://msdn.microsoft.com/en-us/library/windows/desktop/ms677982(v=vs.85).aspx):

+ a trust relationship must exist between source and target domain
+ source and target domain must not be in the same Active Directory forest
+ for source domain all actions will have the PDC Emulator as target; you cannot bind to another DC than the one with the PDC Emulator role
+ Auditing must be enabled in source domain
+ a domain-local group “domain$$$” must be created in source domain
+ a special registry key must be created on PDC Emulator DC in source domain: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\TcpipClientSupport
+ Audit Mode must be turned on in each domain and also Account Management auditing of Success/Failure events must turned to on.
+ the Security Identifier we want to transfer must not already exist in any sidHstory attributes of objects in target domain

Permissions:
For running Powershell code based on SID Cloner you do not necessarily need domain admin credentials in target domain. While read permissions on objects in source domain are sufficient (you are reading the “standard” attribute objectSID there), the permissions to modify the object in target domain by writing the sidHistory value requires more:
+ full access permissions to the object (better OU)
+ special permission “migrateSIDHistory” on the Active Directory domain object in target domain
migrateSidHistoryPermission

With all the requirements settled, you are able to migrate sidHistory by using the sample script, that Jiri published on the SID Cloner Website.

However, the most easy way to use the 4 fold overload with SIDCloner did never work in our tests.
Overload with 4 arguments means, you simply define source and target domain, source account from which you want to take the objectSID and target account where you want to write sidHistory.
This approach will probably never succeed because
a) the strict PDC Emulator access is not guaranteed when using a domain call
b) the credentials of the interactively logged user are obviously not passed to the DsAddSidHistory function inside the SID Cloner dll

Let’s have more findings around this Topics in Part 3 of this blog post.