Skip to main content

Does a Computer Object SID do anything?

This one through me for a loop in class.  While talking about what SYSPREP does to a client, one of the members of the class pointed me to a very interesting article.  I have always been taught that the SID of the computer account is what Windows looks at for assigning security access.  Well, take a minute to read this blog post from Mark Russinovich at Microsoft.

 

OK, let’s put this to the test.  I took a VM from class and created an image of it.  I then deployed this non syspreped image to another VM and started it up in the same environment as the original.  The original was logged off and I had no trouble logging in.  After taking snapshots of the new VM and the DC, I went ahead and renamed the VM to LON-CL3.  In AD Users and Computers, the account associated with the original was renamed.

 

OK, I reapplied the snap shots and brought both identical VMs online.  I was able to log in on both.  On the original, I’m renamed the client and allowed it to reboot. 

image

 

In the image below, you can see a client named LON-CL5.  This is my renamed original.  I was also able to successfully log in using the cloned that is still named LON-CL1.  At this point, security is obviously looking at the SID.

 

Group Policy Updates

I was able to update group policy on the client that was renamed, but the clone with the original name could not update its policy.

image

This points to something other than the SID being used.

 

Resetting the computer account still allowed both clones to log in.

 

I’m out on this one as to what the computer account SID is used for.  Keep an eye on Mark’s blog.  It has so far generate 18 pages of comments.

Comments

Popular posts from this blog

Adding a Comment to a GPO with PowerShell

As I'm writing this article, I'm also writing a customization for a PowerShell course I'm teaching next week in Phoenix.  This customization deals with Group Policy and PowerShell.  For those of you who attend my classes may already know this, but I sit their and try to ask the questions to myself that others may ask as I present the material.  I finished up my customization a few hours ago and then I realized that I did not add in how to put a comment on a GPO.  This is a feature that many Group Policy Administrators may not be aware of. This past summer I attended a presentation at TechEd on Group Policy.  One organization in the crowd had over 5,000 Group Policies.  In an environment like that, the comment section can be priceless.  I always like to write in the comment section why I created the policy so I know its purpose next week after I've completed 50 other tasks and can't remember what I did 5 minutes ago. In the Group Policy module for PowerShell V3, th

Return duplicate values from a collection with PowerShell

If you have a collection of objects and you want to remove any duplicate items, it is fairly simple. # Create a collection with duplicate values $Set1 = 1 , 1 , 2 , 2 , 3 , 4 , 5 , 6 , 7 , 1 , 2   # Remove the duplicate values. $Set1 | Select-Object -Unique 1 2 3 4 5 6 7 What if you want only the duplicate values and nothing else? # Create a collection with duplicate values $Set1 = 1 , 1 , 2 , 2 , 3 , 4 , 5 , 6 , 7 , 1 , 2   #Create a second collection with duplicate values removed. $Set2 = $Set1 | Select-Object -Unique   # Return only the duplicate values. ( Compare-Object -ReferenceObject $Set2 -DifferenceObject $Set1 ) . InputObject | Select-Object – Unique 1 2 This works with objects as well as numbers.  The first command creates a collection with 2 duplicates of both 1 and 2.   The second command creates another collection with the duplicates filtered out.  The Compare-Object cmdlet will first find items that are diffe

How to list all the AD LDS instances on a server

AD LDS allows you to provide directory services to applications that are free of the confines of Active Directory.  To list all the AD LDS instances on a server, follow this procedure: Log into the server in question Open a command prompt. Type dsdbutil and press Enter Type List Instances and press Enter . You will receive a list of the instance name, both the LDAP and SSL port numbers, the location of the database, and its status.