Windows 8.1

Security – Local Administrator Password Solution LAPS

Since Windows Server 2008, we can use Group Policy Preferences to set a password for Local Administrator on all workstations in an OU. In May 2014, Microsoft released a patch to remove this feature. KB2962486

In fact, the password was stored insecurely. It was crypted using a key which is now public MSDN. This is a security leak, password are sent in “clear” and several time by day, using GPO application. If KB2928120 is installed on your system, you can’t no more use GPO to define password for:

  • Drive Maps.
  • Local Users.
  • Scheduled Tasks.
  • Services.
  • Data Sources.

With the Security patch, Microsoft provided a Powershell script to change local password remotely.

Since few days, Microsoft released a new tool: Local Administrator Password Solution (LAPS). With this tool, computers are able to randomly change password for local administrator and store it in Active Directory attribute.

To setup Local Administrator Password Solution, we need to do 6 steps:

  • Install Management Server.
  • Modify Active Directory to create attributes.
  • Set User rights.
  • Install LAPS agent on workstations.
  • Create GPO to define Password Policy.
  • Check data and user rights.

Management Server

Management server provide several tools to manage password information: Powershell cmdlet, GUI to recover password and GPO template.

  • Download LAPS binaries (x64 and x86) files from Microsoft:
LAPS Binaries

LAPS Binaries

  • On the Management Server, start LAPS.x64.msi:
LAPS x64

LAPS x64

  • Select Management Tools features and finish the installation:
LAPS Management Features

Management Features

LAPS Installation

Installation

  • Now, you have the LAPS GUI:
GUI

GUI

Active Directory Modification

LAPS Agent will store its password into Active Directory attribute: ms-Mcs-AdmPwd on a Computer object. We need to extend the Schema:

  • On the Management Server, start Powershell and Import LAPS Module with Import-module admpwd.ps
Import Module

Import Module

  • Extend the Schema with the cmdlet Update-AdmPwdADSchema
Update Schema

Update Schema

User Rights

Local Password will be stored in ms-Mcs-AdmPwd attribute. It means that all users with privileges on the OU can read it.

  • If you want to remove group to be able to read Password, remove All extended rights. For exemple, SCCM_Admins group will not have the right to read Local Password:
Remove Right to Read

Remove Right to Read

  • We need to create an Active Directory group which contains all granted users:
Granted Group

Granted Group

  • Read rights for the new group on specific OU with cmdlet Set-AdmPwdReadPasswordPermission -OrgUnit “OU_DN” -AllowedPrincipals “Group”
Read Right on OU for Group

Read Rights on OU for Group

  • Reset rights for the new group on specific OU with cmdlet Set-AdmPwdResetPasswordPermission -OrgUnit “OU_DN” -AllowedPrincipals “Group”
Reset Right OU

Reset Rights on OU

  • Allow computer object to set Password on itself with Set-AdmPwdComputerSelfPermission -OrgUnit “OU_DN” :
Computer Right

Computer Rights

  • You can check effective rights with the cmdlet Find-AdmPwdExtendedrights -identity :”OU_DN” | fl
Find Rights

Find Rights

LAPS Agent

Depend on your system, you need to install x64 or x86 msi file. You can deploy it with SCCM, GPO, or something else.

  • The installation of the Agent is simple: LAPS.x64.msi /q
LAPS Agent Installation

LAPS Agent Installation

  • To check if the software is installed. go to Add Remove Program:
LAPS Programs

LAPS Programs

GPO Password Policy

LAPS Agent will get its information from Group Policy. When we installed the Management Server, we also imported template for GPO.

  • On the management server, create a GPO under the Workstation’s OU:
GPO Local  Admin Password

GPO Local Admin Password

  • Specify your criteria
    • Path: Computer/Policies/Administrative Templates/LAPS.
    • Enable Local Admin Password Management: Enabled.
    • Password Setting: Enabled. You can chosse password complexity, length, …
    • Do not allow password expiration time longer than required: Enabled.
GPO LAPS

GPO LAPS

  • On your client, force a gpupdate:
Gpupdate Force

Gpupdate Force

Verification

Once the computer finished its gpupdate, it will change its local admin password and send it to Active Directory.

  • You can check the information in Active Directory User and Computer, on the computer object, ms-Mcs-AdmPwd:
LAPS ms-Mcs-AdmPwd

LAPS ms-Mcs-AdmPwd

  • If you start LAPS UI with a granted user:
LAPS UI

LAPS UI

  • With Powershell, the cmdlet Get-AdmPwdPassword -ComputerName computerName
Get Password Powershell

Get Password Powershell

 

Congratulation, you successfully set up Local Administrator Password Solution from Microsoft. 🙂

More

You could get more information about LAPS here.

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