Removing Users From The Local Administrators Group
April 26th, 2018
Learn how to remove admin rights from users and to understand the options available for modifying local group membership of your clients in this post. If you have hundreds – or even thousands – of desktops, it is not feasible to do this manually. Fortunately, Microsoft provides two mechanisms in Group Policy to manage local group membership. The first is a Group Policy extension called Restricted Groups. Restricted Groups allows you to overwrite the existing local group with what you have configured in the Group Policy setting. The other option is within Group Policy Preferences. The Local Users and Groups extension allows you to modify the local group membership without overwriting the existing groups. Additionally, Microsoft offers a tool called LAPS, (Local Administrator Password Solution). When a particular scenario is more complex than these allow, scripts can be used to address as well.
Why Remove Administrator Rights?
Before we get into the details, let’s discuss why you are removing admin rights in the first place. On the surface, it is as straightforward as saying, “Ah, users with unnecessary admin rights is bad, Jason”. This is a simple enough, and a quite accurate statement. But if it were that easy, it would already be done, and you wouldn’t need to be reading this post. More likely, a security initiative has prompted you to move to a least privilege model and/or better manage administrative accounts on endpoints.
The First Step is Discovery
The first step is understanding where administrative access exists. It will be good to have a baseline to refer to, and find any rogue or forgotten access. BeyondTrust offers a free tool called the PowerBroker Privilege Discovery and Reporting Tool (DART) to get you started. DART will help reveal privileges not only on your Windows assets, but also for Mac, Linux, and Unix throughout your organization. Below are a couple handy reports generated by DART.
Restricted Groups can be configured by opening a GPO and navigating to the following location:
Computer Configuration/Policies/Windows Settings/Security Settings/Restricted Groups
If you create a Restricted Group for the Local Administrators group, the GPO will overwrite the existing local group membership and set the membership to whatever has been configured in the GPO. If a user adds himself to the local administrators group, the next time the policy refreshes, the local group membership will reset back to what is defined in the Restricted Group. Ideally, you are adhering to a least privilege model and most of your users won’t have the access rights to manage the local administrators group.
Group Policy Preferences
Another option to manage local group membership is to use Group Policy Preferences (GPP). Group Policy Preferences was introduced in Windows Server 2008 after Microsoft acquired DesktopStandard Corp in 2006 (full disclosure: BeyondTrust was spun out of that transaction).
To configure Group Policy Preferences, simply open a GPO and navigate to Preferences, then expand Control Panel Settings.
When you right-click and create a new policy, you will have the option to add, remove or even modify local group membership. This method of managing local group membership provides more flexibility over Restricted Groups. In the example below, the policy will remove all members of the local administrators group and add the Domain Admins group and a local user back
Note: In previous versions of Preferences you could change the password for the Local Administrator. Due to security issues Microsoft deprecated this ability and since released LAPS – more on this later in this article.
Sometimes it is not as simple as taking some objects out and putting others into the local administrators group as one or two policies. At times, you may need to accommodate a varying number of scenarios which will be difficult if relying on Restricted Groups, or GP Preferences. Though a more complex approach, you can use a script to manage group membership based on unique settings.
What’s going to break if you do this? And how do you fix it?
Once you have decided on your strategy to remove admin rights, it is time to consider the things that will break when you actually take the administrator privileges away from users.
Typically, there will be several applications that your business relies on that will require administrator privileges to run. There will also be system tasks that users will no longer be able to run because they require administrator privileges. Also, users will no longer be able to install most applications since they also require administrator privileges.
These are challenges all organizations will face when removing administrator privileges from end users, even in Windows 10 deployments. This is where PowerBroker for Windows comes to the rescue. PowerBroker for Windows can elevate these apps, tasks, and installs, dynamically without impacting end users. You can even measure your progress with robust reporting capabilities that include automatic discovery of applications that require administrator privileges in your enterprise. It will also reveal how many user accounts have local administrator privileges, as shown below.
What about passwords?
At this point, you have successfully managed the accounts with administrative rights, and ensured that users can still carry out their day to day operations without them. That leaves one more key item – passwords. Most, if not all of you have password age and complexity policies in place for your users. Unfortunately, many of your users have their passwords written on a post-it in a safe, or under their keyboard, whichever is more convenient. While there isn’t much we can do to solve that problem, we can help you properly manage enterprise, local, and service account passwords that need to retain privileged access.
One option is Microsoft’s Local Administrator Password Solution. LAPS can change the Local Administrator password for domain joined machines, but it is quite limited, most notably…
1) LAPS requires an AD schema exchange. This may not be an issue for your company, but it is definitely a consideration.
2) You can only manage the Local Administrator, or a custom Admin account, BUT only on domain-joined machines.
3) It goes without saying, but this only works for Windows systems. You will require additional tools for your Mac, Linux, and Unix systems as well as for other devices, (Routers, Phone Equipment, etc.).
A complete solution is to use a privileged password management solution that can manage all accounts within your organization. PowerBroker Password Safe is used for this purpose. There are no schema changes to be made, and it isn’t limited by the operating system or domain membership. In addition, management, reporting, and auditing are performed by the same central platform as the PowerBroker for Windows product mentioned above.
There are several mechanisms for removing admin rights from users. As you consider the right path for your organization, consider the steps and solutions above – these recommendations are built with an admin’s time in mind!