Tag Archives: Amazon EC2 for Windows Server

How to Delegate Administration of Your AWS Managed Microsoft AD Directory to Your On-Premises Active Directory Users

Post Syndicated from Vijay Sharma original https://aws.amazon.com/blogs/security/how-to-delegate-administration-of-your-aws-managed-microsoft-ad-directory-to-your-on-premises-active-directory-users/

You can now enable your on-premises users administer your AWS Directory Service for Microsoft Active Directory, also known as AWS Managed Microsoft AD. Using an Active Directory (AD) trust and the new AWS delegated AD security groups, you can grant administrative permissions to your on-premises users by managing group membership in your on-premises AD directory. This simplifies how you manage who can perform administration. It also makes it easier for your administrators because they can sign in to their existing workstation with their on-premises AD credential to administer your AWS Managed Microsoft AD.

AWS created new domain local AD security groups (AWS delegated groups) in your AWS Managed Microsoft AD directory. Each AWS delegated group has unique AD administrative permissions. Users that are members in the new AWS delegated groups get permissions to perform administrative tasks, such as add users, configure fine-grained password policies and enable Microsoft enterprise Certificate Authority. Because the AWS delegated groups are domain local in scope, you can use them through an AD Trust to your on-premises AD. This eliminates the requirement to create and use separate identities to administer your AWS Managed Microsoft AD. Instead, by adding selected on-premises users to desired AWS delegated groups, you can grant your administrators some or all of the permissions. You can simplify this even further by adding on-premises AD security groups to the AWS delegated groups. This enables you to add and remove users from your on-premises AD security group so that they can manage administrative permissions in your AWS Managed Microsoft AD.

In this blog post, I will show you how to delegate permissions to your on-premises users to perform an administrative task–configuring fine-grained password policies–in your AWS Managed Microsoft AD directory. You can follow the steps in this post to delegate other administrative permissions, such as configuring group Managed Service Accounts and Kerberos constrained delegation, to your on-premises users.

Background

Until now, AWS Managed Microsoft AD delegated administrative permissions for your directory by creating AD security groups in your Organization Unit (OU) and authorizing these AWS delegated groups for common administrative activities. The admin user in your directory created user accounts within your OU, and granted these users permissions to administer your directory by adding them to one or more of these AWS delegated groups.

However, if you used your AWS Managed Microsoft AD with a trust to an on-premises AD forest, you couldn’t add users from your on-premises directory to these AWS delegated groups. This is because AWS created the AWS delegated groups with global scope, which restricts adding users from another forest. This necessitated that you create different user accounts in AWS Managed Microsoft AD for the purpose of administration. As a result, AD administrators typically had to remember additional credentials for AWS Managed Microsoft AD.

To address this, AWS created new AWS delegated groups with domain local scope in a separate OU called AWS Delegated Groups. These new AWS delegated groups with domain local scope are more flexible and permit adding users and groups from other domains and forests. This allows your admin user to delegate your on-premises users and groups administrative permissions to your AWS Managed Microsoft AD directory.

Note: If you already have an existing AWS Managed Microsoft AD directory containing the original AWS delegated groups with global scope, AWS preserved the original AWS delegated groups in the event you are currently using them with identities in AWS Managed Microsoft AD. AWS recommends that you transition to use the new AWS delegated groups with domain local scope. All newly created AWS Managed Microsoft AD directories have the new AWS delegated groups with domain local scope only.

Now, I will show you the steps to delegate administrative permissions to your on-premises users and groups to configure fine-grained password policies in your AWS Managed Microsoft AD directory.

Prerequisites

For this post, I assume you are familiar with AD security groups and how security group scope rules work. I also assume you are familiar with AD trusts.

The instructions in this blog post require you to have the following components running:

Solution overview

I will now show you how to manage which on-premises users have delegated permissions to administer your directory by efficiently using on-premises AD security groups to manage these permissions. I will do this by:

  1. Adding on-premises groups to an AWS delegated group. In this step, you sign in to management instance connected to AWS Managed Microsoft AD directory as admin user and add on-premises groups to AWS delegated groups.
  2. Administer your AWS Managed Microsoft AD directory as on-premises user. In this step, you sign in to a workstation connected to your on-premises AD using your on-premises credentials and administer your AWS Managed Microsoft AD directory.

For the purpose of this blog, I already have an on-premises AD directory (in this case, on-premises.com). I also created an AWS Managed Microsoft AD directory (in this case, corp.example.com) that I use with Amazon RDS for SQL Server. To enable Integrated Windows Authentication to my on-premises.com domain, I established a one-way outgoing trust from my AWS Managed Microsoft AD directory to my on-premises AD directory. To administer my AWS Managed Microsoft AD, I created an Amazon EC2 for Windows Server instance (in this case, Cloud Management). I also have an on-premises workstation (in this case, On-premises Management), that is connected to my on-premises AD directory.

The following diagram represents the relationships between the on-premises AD and the AWS Managed Microsoft AD directory.

The left side represents the AWS Cloud containing AWS Managed Microsoft AD directory. I connected the directory to the on-premises AD directory via a 1-way forest trust relationship. When AWS created my AWS Managed Microsoft AD directory, AWS created a group called AWS Delegated Fine Grained Password Policy Administrators that has permissions to configure fine-grained password policies in AWS Managed Microsoft AD.

The right side of the diagram represents the on-premises AD directory. I created a global AD security group called On-premises fine grained password policy admins and I configured it so all members can manage fine grained password policies in my on-premises AD. I have two administrators in my company, John and Richard, who I added as members of On-premises fine grained password policy admins. I want to enable John and Richard to also manage fine grained password policies in my AWS Managed Microsoft AD.

While I could add John and Richard to the AWS Delegated Fine Grained Password Policy Administrators individually, I want a more efficient way to delegate and remove permissions for on-premises users to manage fine grained password policies in my AWS Managed Microsoft AD. In fact, I want to assign permissions to the same people that manage password policies in my on-premises directory.

Diagram showing delegation of administrative permissions to on-premises users

To do this, I will:

  1. As admin user, add the On-premises fine grained password policy admins as member of the AWS Delegated Fine Grained Password Policy Administrators security group from my Cloud Management machine.
  2. Manage who can administer password policies in my AWS Managed Microsoft AD directory by adding and removing users as members of the On-premises fine grained password policy admins. Doing so enables me to perform all my delegation work in my on-premises directory without the need to use a remote desktop protocol (RDP) session to my Cloud Management instance. In this case, Richard, who is a member of On-premises fine grained password policy admins group can now administer AWS Managed Microsoft AD directory from On-premises Management workstation.

Although I’m showing a specific case using fine grained password policy delegation, you can do this with any of the new AWS delegated groups and your on-premises groups and users.

Let’s get started.

Step 1 – Add on-premises groups to AWS delegated groups

In this step, open an RDP session to the Cloud Management instance and sign in as the admin user in your AWS Managed Microsoft AD directory. Then, add your users and groups from your on-premises AD to AWS delegated groups in AWS Managed Microsoft AD directory. In this example, I do the following:

  1. Sign in to the Cloud Management instance with the user name admin and the password that you set for the admin user when you created your directory.
  2. Open the Microsoft Windows Server Manager and navigate to Tools > Active Directory Users and Computers.
  3. Switch to the tree view and navigate to corp.example.com > AWS Delegated Groups. Right-click AWS Delegated Fine Grained Password Policy Administrators and select Properties.
  4. In the AWS Delegated Fine Grained Password Policy window, switch to Members tab and choose Add.
  5. In the Select Users, Contacts, Computers, Service Accounts, or Groups window, choose Locations.
  6. In the Locations window, select on-premises.com domain and choose OK.
  7. In the Enter the object names to select box, enter on-premises fine grained password policy admins and choose Check Names.
  8. Because I have a 1-way trust from AWS Managed Microsoft AD to my on-premises AD, Windows prompts me to enter credentials for an on-premises user account that has permissions to complete the search. If I had a 2-way trust and the admin account in my AWS Managed Microsoft AD has permissions to read my on-premises directory, Windows will not prompt me.In the Windows Security window, enter the credentials for an account with permissions for on-premises.com and choose OK.
  9. Click OK to add On-premises fine grained password policy admins group as a member of the AWS Delegated Fine Grained Password Policy Administrators group in your AWS Managed Microsoft AD directory.

At this point, any user that is a member of On-premises fine grained password policy admins group has permissions to manage password policies in your AWS Managed Microsoft AD directory.

Step 2 – Administer your AWS Managed Microsoft AD as on-premises user

Any member of the on-premises group(s) that you added to an AWS delegated group inherited the permissions of the AWS delegated group.

In this example, Richard signs in to the On-premises Management instance. Because Richard inherited permissions from Delegated Fine Grained Password Policy Administrators, he can now administer fine grained password policies in the AWS Managed Microsoft AD directory using on-premises credentials.

  1. Sign in to the On-premises Management instance as Richard.
  2. Open the Microsoft Windows Server Manager and navigate to Tools > Active Directory Users and Computers.
  3. Switch to the tree view, right-click Active Directory Users and Computers, and then select Change Domain.
  4. In the Change Domain window, enter corp.example.com, and then choose OK.
  5. You’ll be connected to your AWS Managed Microsoft AD domain:

Richard can now administer the password policies. Because John is also a member of the AWS delegated group, John can also perform password policy administration the same way.

In future, if Richard moves to another division within the company and you hire Judy as a replacement for Richard, you can simply remove Richard from On-premises fine grained password policy admins group and add Judy to this group. Richard will no longer have administrative permissions, while Judy can now administer password policies for your AWS Managed Microsoft AD directory.

Summary

We’ve tried to make it easier for you to administer your AWS Managed Microsoft AD directory by creating AWS delegated groups with domain local scope. You can add your on-premises AD groups to the AWS delegated groups. You can then control who can administer your directory by managing group membership in your on-premises AD directory. Your administrators can sign in to their existing on-premises workstations using their on-premises credentials and administer your AWS Managed Microsoft AD directory. I encourage you to explore the new AWS delegated security groups by using Active Directory Users and Computers from the management instance for your AWS Managed Microsoft AD. To learn more about AWS Directory Service, see the AWS Directory Service home page. If you have questions, please post them on the Directory Service forum. If you have comments about this post, submit them in the “Comments” section below.

 

How AWS Managed Microsoft AD Helps to Simplify the Deployment and Improve the Security of Active Directory–Integrated .NET Applications

Post Syndicated from Peter Pereira original https://aws.amazon.com/blogs/security/how-aws-managed-microsoft-ad-helps-to-simplify-the-deployment-and-improve-the-security-of-active-directory-integrated-net-applications/

Companies using .NET applications to access sensitive user information, such as employee salary, Social Security Number, and credit card information, need an easy and secure way to manage access for users and applications.

For example, let’s say that your company has a .NET payroll application. You want your Human Resources (HR) team to manage and update the payroll data for all the employees in your company. You also want your employees to be able to see their own payroll information in the application. To meet these requirements in a user-friendly and secure way, you want to manage access to the .NET application by using your existing Microsoft Active Directory identities. This enables you to provide users with single sign-on (SSO) access to the .NET application and to manage permissions using Active Directory groups. You also want the .NET application to authenticate itself to access the database, and to limit access to the data in the database based on the identity of the application user.

Microsoft Active Directory supports these requirements through group Managed Service Accounts (gMSAs) and Kerberos constrained delegation (KCD). AWS Directory Service for Microsoft Active Directory, also known as AWS Managed Microsoft AD, enables you to manage gMSAs and KCD through your administrative account, helping you to migrate and develop .NET applications that need these native Active Directory features.

In this blog post, I give an overview of how to use AWS Managed Microsoft AD to manage gMSAs and KCD and demonstrate how you can configure a gMSA and KCD in six steps for a .NET application:

  1. Create your AWS Managed Microsoft AD.
  2. Create your Amazon RDS for SQL Server database.
  3. Create a gMSA for your .NET application.
  4. Deploy your .NET application.
  5. Configure your .NET application to use the gMSA.
  6. Configure KCD for your .NET application.

Solution overview

The following diagram shows the components of a .NET application that uses Amazon RDS for SQL Server with a gMSA and KCD. The diagram also illustrates authentication and access and is numbered to show the six key steps required to use a gMSA and KCD. To deploy this solution, the AWS Managed Microsoft AD directory must be in the same Amazon Virtual Private Cloud (VPC) as RDS for SQL Server. For this example, my company name is Example Corp., and my directory uses the domain name, example.com.

Diagram showing the components of a .NET application that uses Amazon RDS for SQL Server with a gMSA and KCD

Deploy the solution

The following six steps (numbered to correlate with the preceding diagram) walk you through configuring and using a gMSA and KCD.

1. Create your AWS Managed Microsoft AD directory

Using the Directory Service console, create your AWS Managed Microsoft AD directory in your Amazon VPC. In my example, my domain name is example.com.

Image of creating an AWS Managed Microsoft AD directory in an Amazon VPC

2. Create your Amazon RDS for SQL Server database

Using the RDS console, create your Amazon RDS for SQL Server database instance in the same Amazon VPC where your directory is running, and enable Windows Authentication. To enable Windows Authentication, select your directory in the Microsoft SQL Server Windows Authentication section in the Configure Advanced Settings step of the database creation workflow (see the following screenshot).

In my example, I create my Amazon RDS for SQL Server db-example database, and enable Windows Authentication to allow my db-example database to authenticate against my example.com directory.

Screenshot of configuring advanced settings

3. Create a gMSA for your .NET application

Now that you have deployed your directory, database, and application, you can create a gMSA for your .NET application.

To perform the next steps, you must install the Active Directory administration tools on a Windows server that is joined to your AWS Managed Microsoft AD directory domain. If you do not have a Windows server joined to your directory domain, you can deploy a new Amazon EC2 for Microsoft Windows Server instance and join it to your directory domain.

To create a gMSA for your .NET application:

  1. Log on to the instance on which you installed the Active Directory administration tools by using a user that is a member of the Admins security group or the Managed Service Accounts Admins security group in your organizational unit (OU). For my example, I use the Admin user in the example OU.

Screenshot of logging on to the instance on which you installed the Active Directory administration tools

  1. Identify which .NET application servers (hosts) will run your .NET application. Create a new security group in your OU and add your .NET application servers as members of this new group. This allows a group of application servers to use a single gMSA, instead of creating one gMSA for each server. In my example, I create a group, App_server_grp, in my example OU. I also add Appserver1, which is my .NET application server computer name, as a member of this new group.

Screenshot of creating a new security group

  1. Create a gMSA in your directory by running Windows PowerShell from the Start menu. The basic syntax to create the gMSA at the Windows PowerShell command prompt follows.
    PS C:\Users\admin> New-ADServiceAccount -name [gMSAname] -DNSHostName [domainname] -PrincipalsAllowedToRetrieveManagedPassword [AppServersSecurityGroup] -TrustedForDelegation $truedn <Enter>

    In my example, the gMSAname is gMSAexample, the DNSHostName is example.com, and the PrincipalsAllowedToRetrieveManagedPassword is the recently created security group, App_server_grp.

    PS C:\Users\admin> New-ADServiceAccount -name gMSAexample -DNSHostName example.com -PrincipalsAllowedToRetrieveManagedPassword App_server_grp -TrustedForDelegation $truedn <Enter>

    To confirm you created the gMSA, you can run the Get-ADServiceAccount command from the PowerShell command prompt.

    PS C:\Users\admin> Get-ADServiceAccount gMSAexample <Enter>
    
    DistinguishedName : CN=gMSAexample,CN=Managed Service Accounts,DC=example,DC=com
    Enabled           : True
    Name              : gMSAexample
    ObjectClass       : msDS-GroupManagedServiceAccount
    ObjectGUID        : 24d8b68d-36d5-4dc3-b0a9-edbbb5dc8a5b
    SamAccountName    : gMSAexample$
    SID               : S-1-5-21-2100421304-991410377-951759617-1603
    UserPrincipalName :

    You also can confirm you created the gMSA by opening the Active Directory Users and Computers utility located in your Administrative Tools folder, expand the domain (example.com in my case), and expand the Managed Service Accounts folder.
    Screenshot of confirming the creation of the gMSA

4. Deploy your .NET application

Deploy your .NET application on IIS on Amazon EC2 for Windows Server instances. For this step, I assume you are the application’s expert and already know how to deploy it. Make sure that all of your instances are joined to your directory.

5. Configure your .NET application to use the gMSA

You can configure your .NET application to use the gMSA to enforce strong password security policy and ensure password rotation of your service account. This helps to improve the security and simplify the management of your .NET application. Configure your .NET application in two steps:

  1. Grant to gMSA the required permissions to run your .NET application in the respective application folders. This is a critical step because when you change the application pool identity account to use gMSA, downtime can occur if the gMSA does not have the application’s required permissions. Therefore, make sure you first test the configurations in your development and test environments.
  2. Configure your application pool identity on IIS to use the gMSA as the service account. When you configure a gMSA as the service account, you include the $ at the end of the gMSA name. You do not need to provide a password because AWS Managed Microsoft AD automatically creates and rotates the password. In my example, my service account is gMSAexample$, as shown in the following screenshot.

Screenshot of configuring application pool identity

You have completed all the steps to use gMSA to create and rotate your .NET application service account password! Now, you will configure KCD for your .NET application.

6. Configure KCD for your .NET application

You now are ready to allow your .NET application to have access to other services by using the user identity’s permissions instead of the application service account’s permissions. Note that KCD and gMSA are independent features, which means you do not have to create a gMSA to use KCD. For this example, I am using both features to show how you can use them together. To configure a regular service account such as a user or local built-in account, see the Kerberos constrained delegation with ASP.NET blog post on MSDN.

In my example, my goal is to delegate to the gMSAexample account the ability to enforce the user’s permissions to my db-example SQL Server database, instead of the gMSAexample account’s permissions. For this, I have to update the msDS-AllowedToDelegateTo gMSA attribute. The value for this attribute is the service principal name (SPN) of the service instance that you are targeting, which in this case is the db-example Amazon RDS for SQL Server database.

The SPN format for the msDS-AllowedToDelegateTo attribute is a combination of the service class, the Kerberos authentication endpoint, and the port number. The Amazon RDS for SQL Server Kerberos authentication endpoint format is [database_name].[domain_name]. The value for my msDS-AllowedToDelegateTo attribute is MSSQLSvc/db-example.example.com:1433, where MSSQLSvc and 1433 are the SQL Server Database service class and port number standards, respectively.

Follow these steps to perform the msDS-AllowedToDelegateTo gMSA attribute configuration:

  1. Log on to your Active Directory management instance with a user identity that is a member of the Kerberos Delegation Admins security group. In this case, I will use admin.
  2. Open the Active Directory Users and Groups utility located in your Administrative Tools folder, choose View, and then choose Advanced Features.
  3. Expand your domain name (example.com in this example), and then choose the Managed Service Accounts security group. Right-click the gMSA account for the application pool you want to enable for Kerberos delegation, choose Properties, and choose the Attribute Editor tab.
  4. Search for the msDS-AllowedToDelegateTo attribute on the Attribute Editor tab and choose Edit.
  5. Enter the MSSQLSvc/db-example.example.com:1433 value and choose Add.
    Screenshot of entering the value of the multi-valued string
  6. Choose OK and Apply, and your KCD configuration is complete.

Congratulations! At this point, your application is using a gMSA rather than an embedded static user identity and password, and the application is able to access SQL Server using the identity of the application user. The gMSA eliminates the need for you to rotate the application’s password manually, and it allows you to better scope permissions for the application. When you use KCD, you can enforce access to your database consistently based on user identities at the database level, which prevents improper access that might otherwise occur because of an application error.

Summary

In this blog post, I demonstrated how to simplify the deployment and improve the security of your .NET application by using a group Managed Service Account and Kerberos constrained delegation with your AWS Managed Microsoft AD directory. I also outlined the main steps to get your .NET environment up and running on a managed Active Directory and SQL Server infrastructure. This approach will make it easier for you to build new .NET applications in the AWS Cloud or migrate existing ones in a more secure way.

For additional information about using group Managed Service Accounts and Kerberos constrained delegation with your AWS Managed Microsoft AD directory, see the AWS Directory Service documentation.

To learn more about AWS Directory Service, see the AWS Directory Service home page. If you have questions about this post or its solution, start a new thread on the Directory Service forum.

– Peter

How to Enable LDAPS for Your AWS Microsoft AD Directory

Post Syndicated from Vijay Sharma original https://aws.amazon.com/blogs/security/how-to-enable-ldaps-for-your-aws-microsoft-ad-directory/

Starting today, you can encrypt the Lightweight Directory Access Protocol (LDAP) communications between your applications and AWS Directory Service for Microsoft Active Directory, also known as AWS Microsoft AD. Many Windows and Linux applications use Active Directory’s (AD) LDAP service to read and write sensitive information about users and devices, including personally identifiable information (PII). Now, you can encrypt your AWS Microsoft AD LDAP communications end to end to protect this information by using LDAP Over Secure Sockets Layer (SSL)/Transport Layer Security (TLS), also called LDAPS. This helps you protect PII and other sensitive information exchanged with AWS Microsoft AD over untrusted networks.

To enable LDAPS, you need to add a Microsoft enterprise Certificate Authority (CA) server to your AWS Microsoft AD domain and configure certificate templates for your domain controllers. After you have enabled LDAPS, AWS Microsoft AD encrypts communications with LDAPS-enabled Windows applications, Linux computers that use Secure Shell (SSH) authentication, and applications such as Jira and Jenkins.

In this blog post, I show how to enable LDAPS for your AWS Microsoft AD directory in six steps: 1) Delegate permissions to CA administrators, 2) Add a Microsoft enterprise CA to your AWS Microsoft AD directory, 3) Create a certificate template, 4) Configure AWS security group rules, 5) AWS Microsoft AD enables LDAPS, and 6) Test LDAPS access using the LDP tool.

Assumptions

For this post, I assume you are familiar with following:

Solution overview

Before going into specific deployment steps, I will provide a high-level overview of deploying LDAPS. I cover how you enable LDAPS on AWS Microsoft AD. In addition, I provide some general background about CA deployment models and explain how to apply these models when deploying Microsoft CA to enable LDAPS on AWS Microsoft AD.

How you enable LDAPS on AWS Microsoft AD

LDAP-aware applications (LDAP clients) typically access LDAP servers using Transmission Control Protocol (TCP) on port 389. By default, LDAP communications on port 389 are unencrypted. However, many LDAP clients use one of two standards to encrypt LDAP communications: LDAP over SSL on port 636, and LDAP with StartTLS on port 389. If an LDAP client uses port 636, the LDAP server encrypts all traffic unconditionally with SSL. If an LDAP client issues a StartTLS command when setting up the LDAP session on port 389, the LDAP server encrypts all traffic to that client with TLS. AWS Microsoft AD now supports both encryption standards when you enable LDAPS on your AWS Microsoft AD domain controllers.

You enable LDAPS on your AWS Microsoft AD domain controllers by installing a digital certificate that a CA issued. Though Windows servers have different methods for installing certificates, LDAPS with AWS Microsoft AD requires you to add a Microsoft CA to your AWS Microsoft AD domain and deploy the certificate through autoenrollment from the Microsoft CA. The installed certificate enables the LDAP service running on domain controllers to listen for and negotiate LDAP encryption on port 636 (LDAP over SSL) and port 389 (LDAP with StartTLS).

Background of CA deployment models

You can deploy CAs as part of a single-level or multi-level CA hierarchy. In a single-level hierarchy, all certificates come from the root of the hierarchy. In a multi-level hierarchy, you organize a collection of CAs in a hierarchy and the certificates sent to computers and users come from subordinate CAs in the hierarchy (not the root).

Certificates issued by a CA identify the hierarchy to which the CA belongs. When a computer sends its certificate to another computer for verification, the receiving computer must have the public certificate from the CAs in the same hierarchy as the sender. If the CA that issued the certificate is part of a single-level hierarchy, the receiver must obtain the public certificate of the CA that issued the certificate. If the CA that issued the certificate is part of a multi-level hierarchy, the receiver can obtain a public certificate for all the CAs that are in the same hierarchy as the CA that issued the certificate. If the receiver can verify that the certificate came from a CA that is in the hierarchy of the receiver’s “trusted” public CA certificates, the receiver trusts the sender. Otherwise, the receiver rejects the sender.

Deploying Microsoft CA to enable LDAPS on AWS Microsoft AD

Microsoft offers a standalone CA and an enterprise CA. Though you can configure either as single-level or multi-level hierarchies, only the enterprise CA integrates with AD and offers autoenrollment for certificate deployment. Because you cannot sign in to run commands on your AWS Microsoft AD domain controllers, an automatic certificate enrollment model is required. Therefore, AWS Microsoft AD requires the certificate to come from a Microsoft enterprise CA that you configure to work in your AD domain. When you install the Microsoft enterprise CA, you can configure it to be part of a single-level hierarchy or a multi-level hierarchy. As a best practice, AWS recommends a multi-level Microsoft CA trust hierarchy consisting of a root CA and a subordinate CA. I cover only a multi-level hierarchy in this post.

In a multi-level hierarchy, you configure your subordinate CA by importing a certificate from the root CA. You must issue a certificate from the root CA such that the certificate gives your subordinate CA the right to issue certificates on behalf of the root. This makes your subordinate CA part of the root CA hierarchy. You also deploy the root CA’s public certificate on all of your computers, which tells all your computers to trust certificates that your root CA issues and to trust certificates from any authorized subordinate CA.

In such a hierarchy, you typically leave your root CA offline (inaccessible to other computers in the network) to protect the root of your hierarchy. You leave the subordinate CA online so that it can issue certificates on behalf of the root CA. This multi-level hierarchy increases security because if someone compromises your subordinate CA, you can revoke all certificates it issued and set up a new subordinate CA from your offline root CA. To learn more about setting up a secure CA hierarchy, see Securing PKI: Planning a CA Hierarchy.

When a Microsoft CA is part of your AD domain, you can configure certificate templates that you publish. These templates become visible to client computers through AD. If a client’s profile matches a template, the client requests a certificate from the Microsoft CA that matches the template. Microsoft calls this process autoenrollment, and it simplifies certificate deployment. To enable LDAPS on your AWS Microsoft AD domain controllers, you create a certificate template in the Microsoft CA that generates SSL and TLS-compatible certificates. The domain controllers see the template and automatically import a certificate of that type from the Microsoft CA. The imported certificate enables LDAP encryption.

Steps to enable LDAPS for your AWS Microsoft AD directory

The rest of this post is composed of the steps for enabling LDAPS for your AWS Microsoft AD directory. First, though, I explain which components you must have running to deploy this solution successfully. I also explain how this solution works and include an architecture diagram.

Prerequisites

The instructions in this post assume that you already have the following components running:

  1. An active AWS Microsoft AD directory – To create a directory, follow the steps in Create an AWS Microsoft AD directory.
  2. An Amazon EC2 for Windows Server instance for managing users and groups in your directory – This instance needs to be joined to your AWS Microsoft AD domain and have Active Directory Administration Tools installed. Active Directory Administration Tools installs Active Directory Administrative Center and the LDP tool.
  3. An existing root Microsoft CA or a multi-level Microsoft CA hierarchy – You might already have a root CA or a multi-level CA hierarchy in your on-premises network. If you plan to use your on-premises CA hierarchy, you must have administrative permissions to issue certificates to subordinate CAs. If you do not have an existing Microsoft CA hierarchy, you can set up a new standalone Microsoft root CA by creating an Amazon EC2 for Windows Server instance and installing a standalone root certification authority. You also must create a local user account on this instance and add this user to the local administrator group so that the user has permissions to issue a certificate to a subordinate CA.

The solution setup

The following diagram illustrates the setup with the steps you need to follow to enable LDAPS for AWS Microsoft AD. You will learn how to set up a subordinate Microsoft enterprise CA (in this case, SubordinateCA) and join it to your AWS Microsoft AD domain (in this case, corp.example.com). You also will learn how to create a certificate template on SubordinateCA and configure AWS security group rules to enable LDAPS for your directory.

As a prerequisite, I already created a standalone Microsoft root CA (in this case RootCA) for creating SubordinateCA. RootCA also has a local user account called RootAdmin that has administrative permissions to issue certificates to SubordinateCA. Note that you may already have a root CA or a multi-level CA hierarchy in your on-premises network that you can use for creating SubordinateCA instead of creating a new root CA. If you choose to use your existing on-premises CA hierarchy, you must have administrative permissions on your on-premises CA to issue a certificate to SubordinateCA.

Lastly, I also already created an Amazon EC2 instance (in this case, Management) that I use to manage users, configure AWS security groups, and test the LDAPS connection. I join this instance to the AWS Microsoft AD directory domain.

Diagram showing the process discussed in this post

Here is how the process works:

  1. Delegate permissions to CA administrators (in this case, CAAdmin) so that they can join a Microsoft enterprise CA to your AWS Microsoft AD domain and configure it as a subordinate CA.
  2. Add a Microsoft enterprise CA to your AWS Microsoft AD domain (in this case, SubordinateCA) so that it can issue certificates to your directory domain controllers to enable LDAPS. This step includes joining SubordinateCA to your directory domain, installing the Microsoft enterprise CA, and obtaining a certificate from RootCA that grants SubordinateCA permissions to issue certificates.
  3. Create a certificate template (in this case, ServerAuthentication) with server authentication and autoenrollment enabled so that your AWS Microsoft AD directory domain controllers can obtain certificates through autoenrollment to enable LDAPS.
  4. Configure AWS security group rules so that AWS Microsoft AD directory domain controllers can connect to the subordinate CA to request certificates.
  5. AWS Microsoft AD enables LDAPS through the following process:
    1. AWS Microsoft AD domain controllers request a certificate from SubordinateCA.
    2. SubordinateCA issues a certificate to AWS Microsoft AD domain controllers.
    3. AWS Microsoft AD enables LDAPS for the directory by installing certificates on the directory domain controllers.
  6. Test LDAPS access by using the LDP tool.

I now will show you these steps in detail. I use the names of components—such as RootCA, SubordinateCA, and Management—and refer to users—such as Admin, RootAdmin, and CAAdmin—to illustrate who performs these steps. All component names and user names in this post are used for illustrative purposes only.

Deploy the solution

Step 1: Delegate permissions to CA administrators


In this step, you delegate permissions to your users who manage your CAs. Your users then can join a subordinate CA to your AWS Microsoft AD domain and create the certificate template in your CA.

To enable use with a Microsoft enterprise CA, AWS added a new built-in AD security group called AWS Delegated Enterprise Certificate Authority Administrators that has delegated permissions to install and administer a Microsoft enterprise CA. By default, your directory Admin is part of the new group and can add other users or groups in your AWS Microsoft AD directory to this security group. If you have trust with your on-premises AD directory, you can also delegate CA administrative permissions to your on-premises users by adding on-premises AD users or global groups to this new AD security group.

To create a new user (in this case CAAdmin) in your directory and add this user to the AWS Delegated Enterprise Certificate Authority Administrators security group, follow these steps:

  1. Sign in to the Management instance using RDP with the user name admin and the password that you set for the admin user when you created your directory.
  2. Launch the Microsoft Windows Server Manager on the Management instance and navigate to Tools > Active Directory Users and Computers.
    Screnshot of the menu including the "Active Directory Users and Computers" choice
  3. Switch to the tree view and navigate to corp.example.com > CORP > Users. Right-click Users and choose New > User.
    Screenshot of choosing New > User
  4. Add a new user with the First name CA, Last name Admin, and User logon name CAAdmin.
    Screenshot of completing the "New Object - User" boxes
  5. In the Active Directory Users and Computers tool, navigate to corp.example.com > AWS Delegated Groups. In the right pane, right-click AWS Delegated Enterprise Certificate Authority Administrators and choose Properties.
    Screenshot of navigating to AWS Delegated Enterprise Certificate Authority Administrators > Properties
  6. In the AWS Delegated Enterprise Certificate Authority Administrators window, switch to the Members tab and choose Add.
    Screenshot of the "Members" tab of the "AWS Delegate Enterprise Certificate Authority Administrators" window
  7. In the Enter the object names to select box, type CAAdmin and choose OK.
    Screenshot showing the "Enter the object names to select" box
  8. In the next window, choose OK to add CAAdmin to the AWS Delegated Enterprise Certificate Authority Administrators security group.
    Screenshot of adding "CA Admin" to the "AWS Delegated Enterprise Certificate Authority Administrators" security group
  9. Also add CAAdmin to the AWS Delegated Server Administrators security group so that CAAdmin can RDP in to the Microsoft enterprise CA machine.
    Screenshot of adding "CAAdmin" to the "AWS Delegated Server Administrators" security group also so that "CAAdmin" can RDP in to the Microsoft enterprise CA machine

 You have granted CAAdmin permissions to join a Microsoft enterprise CA to your AWS Microsoft AD directory domain.

Step 2: Add a Microsoft enterprise CA to your AWS Microsoft AD directory


In this step, you set up a subordinate Microsoft enterprise CA and join it to your AWS Microsoft AD directory domain. I will summarize the process first and then walk through the steps.

First, you create an Amazon EC2 for Windows Server instance called SubordinateCA and join it to the domain, corp.example.com. You then publish RootCA’s public certificate and certificate revocation list (CRL) to SubordinateCA’s local trusted store. You also publish RootCA’s public certificate to your directory domain. Doing so enables SubordinateCA and your directory domain controllers to trust RootCA. You then install the Microsoft enterprise CA service on SubordinateCA and request a certificate from RootCA to make SubordinateCA a subordinate Microsoft CA. After RootCA issues the certificate, SubordinateCA is ready to issue certificates to your directory domain controllers.

Note that you can use an Amazon S3 bucket to pass the certificates between RootCA and SubordinateCA.

In detail, here is how the process works, as illustrated in the preceding diagram:

  1. Set up an Amazon EC2 instance joined to your AWS Microsoft AD directory domain – Create an Amazon EC2 for Windows Server instance to use as a subordinate CA, and join it to your AWS Microsoft AD directory domain. For this example, the machine name is SubordinateCA and the domain is corp.example.com.
  2. Share RootCA’s public certificate with SubordinateCA – Log in to RootCA as RootAdmin and start Windows PowerShell with administrative privileges. Run the following commands to copy RootCA’s public certificate and CRL to the folder c:\rootcerts on RootCA.
    New-Item c:\rootcerts -type directory
    copy C:\Windows\system32\certsrv\certenroll\*.cr* c:\rootcerts

    Upload RootCA’s public certificate and CRL from c:\rootcerts to an S3 bucket by following the steps in How Do I Upload Files and Folders to an S3 Bucket.

The following screenshot shows RootCA’s public certificate and CRL uploaded to an S3 bucket.
Screenshot of RootCA’s public certificate and CRL uploaded to the S3 bucket

  1. Publish RootCA’s public certificate to your directory domain – Log in to SubordinateCA as the CAAdmin. Download RootCA’s public certificate and CRL from the S3 bucket by following the instructions in How Do I Download an Object from an S3 Bucket? Save the certificate and CRL to the C:\rootcerts folder on SubordinateCA. Add RootCA’s public certificate and the CRL to the local store of SubordinateCA and publish RootCA’s public certificate to your directory domain by running the following commands using Windows PowerShell with administrative privileges.
    certutil –addstore –f root <path to the RootCA public certificate file>
    certutil –addstore –f root <path to the RootCA CRL file>
    certutil –dspublish –f <path to the RootCA public certificate file> RootCA
  2. Install the subordinate Microsoft enterprise CA – Install the subordinate Microsoft enterprise CA on SubordinateCA by following the instructions in Install a Subordinate Certification Authority. Ensure that you choose Enterprise CA for Setup Type to install an enterprise CA.

For the CA Type, choose Subordinate CA.

  1. Request a certificate from RootCA – Next, copy the certificate request on SubordinateCA to a folder called c:\CARequest by running the following commands using Windows PowerShell with administrative privileges.
    New-Item c:\CARequest -type directory
    Copy c:\*.req C:\CARequest

    Upload the certificate request to the S3 bucket.
    Screenshot of uploading the certificate request to the S3 bucket

  1. Approve SubordinateCA’s certificate request – Log in to RootCA as RootAdmin and download the certificate request from the S3 bucket to a folder called CARequest. Submit the request by running the following command using Windows PowerShell with administrative privileges.
    certreq -submit <path to certificate request file>

    In the Certification Authority List window, choose OK.
    Screenshot of the Certification Authority List window

Navigate to Server Manager > Tools > Certification Authority on RootCA.
Screenshot of "Certification Authority" in the drop-down menu

In the Certification Authority window, expand the ROOTCA tree in the left pane and choose Pending Requests. In the right pane, note the value in the Request ID column. Right-click the request and choose All Tasks > Issue.
Screenshot of noting the value in the "Request ID" column

  1. Retrieve the SubordinateCA certificate – Retrieve the SubordinateCA certificate by running following command using Windows PowerShell with administrative privileges. The command includes the <RequestId> that you noted in the previous step.
    certreq –retrieve <RequestId> <drive>:\subordinateCA.crt

    Upload SubordinateCA.crt to the S3 bucket.

  1. Install the SubordinateCA certificate – Log in to SubordinateCA as the CAAdmin and download SubordinateCA.crt from the S3 bucket. Install the certificate by running following commands using Windows PowerShell with administrative privileges.
    certutil –installcert c:\subordinateCA.crt
    start-service certsvc
  2. Delete the content that you uploaded to S3  As a security best practice, delete all the certificates and CRLs that you uploaded to the S3 bucket in the previous steps because you already have installed them on SubordinateCA.

You have finished setting up the subordinate Microsoft enterprise CA that is joined to your AWS Microsoft AD directory domain. Now you can use your subordinate Microsoft enterprise CA to create a certificate template so that your directory domain controllers can request a certificate to enable LDAPS for your directory.

Step 3: Create a certificate template


In this step, you create a certificate template with server authentication and autoenrollment enabled on SubordinateCA. You create this new template (in this case, ServerAuthentication) by duplicating an existing certificate template (in this case, Domain Controller template) and adding server authentication and autoenrollment to the template.

Follow these steps to create a certificate template:

  1. Log in to SubordinateCA as CAAdmin.
  2. Launch Microsoft Windows Server Manager. Select Tools > Certification Authority.
  3. In the Certificate Authority window, expand the SubordinateCA tree in the left pane. Right-click Certificate Templates, and choose Manage.
    Screenshot of choosing "Manage" under "Certificate Template"
  4. In the Certificate Templates Console window, right-click Domain Controller and choose Duplicate Template.
    Screenshot of the Certificate Templates Console window
  5. In the Properties of New Template window, switch to the General tab and change the Template display name to ServerAuthentication.
    Screenshot of the "Properties of New Template" window
  6. Switch to the Security tab, and choose Domain Controllers in the Group or user names section. Select the Allow check box for Autoenroll in the Permissions for Domain Controllers section.
    Screenshot of the "Permissions for Domain Controllers" section of the "Properties of New Template" window
  7. Switch to the Extensions tab, choose Application Policies in the Extensions included in this template section, and choose Edit
    Screenshot of the "Extensions" tab of the "Properties of New Template" window
  8. In the Edit Application Policies Extension window, choose Client Authentication and choose Remove. Choose OK to create the ServerAuthentication certificate template. Close the Certificate Templates Console window.
    Screenshot of the "Edit Application Policies Extension" window
  9. In the Certificate Authority window, right-click Certificate Templates, and choose New > Certificate Template to Issue.
    Screenshot of choosing "New" > "Certificate Template to Issue"
  10. In the Enable Certificate Templates window, choose ServerAuthentication and choose OK.
    Screenshot of the "Enable Certificate Templates" window

You have finished creating a certificate template with server authentication and autoenrollment enabled on SubordinateCA. Your AWS Microsoft AD directory domain controllers can now obtain a certificate through autoenrollment to enable LDAPS.

Step 4: Configure AWS security group rules


In this step, you configure AWS security group rules so that your directory domain controllers can connect to the subordinate CA to request a certificate. To do this, you must add outbound rules to your directory’s AWS security group (in this case, sg-4ba7682d) to allow all outbound traffic to SubordinateCA’s AWS security group (in this case, sg-6fbe7109) so that your directory domain controllers can connect to SubordinateCA for requesting a certificate. You also must add inbound rules to SubordinateCA’s AWS security group to allow all incoming traffic from your directory’s AWS security group so that the subordinate CA can accept incoming traffic from your directory domain controllers.

Follow these steps to configure AWS security group rules:

  1. Log in to the Management instance as Admin.
  2. Navigate to the EC2 console.
  3. In the left pane, choose Network & Security > Security Groups.
  4. In the right pane, choose the AWS security group (in this case, sg-6fbe7109) of SubordinateCA.
  5. Switch to the Inbound tab and choose Edit.
  6. Choose Add Rule. Choose All traffic for Type and Custom for Source. Enter your directory’s AWS security group (in this case, sg-4ba7682d) in the Source box. Choose Save.
    Screenshot of adding an inbound rule
  7. Now choose the AWS security group (in this case, sg-4ba7682d) of your AWS Microsoft AD directory, switch to the Outbound tab, and choose Edit.
  8. Choose Add Rule. Choose All traffic for Type and Custom for Destination. Enter your directory’s AWS security group (in this case, sg-6fbe7109) in the Destination box. Choose Save.

You have completed the configuration of AWS security group rules to allow traffic between your directory domain controllers and SubordinateCA.

Step 5: AWS Microsoft AD enables LDAPS


The AWS Microsoft AD domain controllers perform this step automatically by recognizing the published template and requesting a certificate from the subordinate Microsoft enterprise CA. The subordinate CA can take up to 180 minutes to issue certificates to the directory domain controllers. The directory imports these certificates into the directory domain controllers and enables LDAPS for your directory automatically. This completes the setup of LDAPS for the AWS Microsoft AD directory. The LDAP service on the directory is now ready to accept LDAPS connections!

Step 6: Test LDAPS access by using the LDP tool


In this step, you test the LDAPS connection to the AWS Microsoft AD directory by using the LDP tool. The LDP tool is available on the Management machine where you installed Active Directory Administration Tools. Before you test the LDAPS connection, you must wait up to 180 minutes for the subordinate CA to issue a certificate to your directory domain controllers.

To test LDAPS, you connect to one of the domain controllers using port 636. Here are the steps to test the LDAPS connection:

  1. Log in to Management as Admin.
  2. Launch the Microsoft Windows Server Manager on Management and navigate to Tools > Active Directory Users and Computers.
  3. Switch to the tree view and navigate to corp.example.com > CORP > Domain Controllers. In the right pane, right-click on one of the domain controllers and choose Properties. Copy the DNS name of the domain controller.
    Screenshot of copying the DNS name of the domain controller
  4. Launch the LDP.exe tool by launching Windows PowerShell and running the LDP.exe command.
  5. In the LDP tool, choose Connection > Connect.
    Screenshot of choosing "Connnection" > "Connect" in the LDP tool
  6. In the Server box, paste the DNS name you copied in the previous step. Type 636 in the Port box. Choose OK to test the LDAPS connection to port 636 of your directory.
    Screenshot of completing the boxes in the "Connect" window
  7. You should see the following message to confirm that your LDAPS connection is now open.

You have completed the setup of LDAPS for your AWS Microsoft AD directory! You can now encrypt LDAP communications between your Windows and Linux applications and your AWS Microsoft AD directory using LDAPS.

Summary

In this blog post, I walked through the process of enabling LDAPS for your AWS Microsoft AD directory. Enabling LDAPS helps you protect PII and other sensitive information exchanged over untrusted networks between your Windows and Linux applications and your AWS Microsoft AD. To learn more about how to use AWS Microsoft AD, see the Directory Service documentation. For general information and pricing, see the Directory Service home page.

If you have comments about this blog post, submit a comment in the “Comments” section below. If you have implementation or troubleshooting questions, start a new thread on the Directory Service forum.

– Vijay

How to Configure Even Stronger Password Policies to Help Meet Your Security Standards by Using AWS Directory Service for Microsoft Active Directory

Post Syndicated from Ravi Turlapati original https://aws.amazon.com/blogs/security/how-to-configure-even-stronger-password-policies-to-help-meet-your-security-standards-by-using-aws-directory-service-for-microsoft-active-directory/

With AWS Directory Service for Microsoft Active Directory (Enterprise Edition), also known as AWS Microsoft AD, you can now create and enforce custom password policies for your Microsoft Windows users. AWS Microsoft AD now includes five empty password policies that you can edit and apply with standard Microsoft password policy tools such as Active Directory Administrative Center (ADAC). With this capability, you are no longer limited to the default Windows password policy. Now, you can configure even stronger password policies and define lockout policies that specify when to lock out an account after login failures.

In this blog post, I demonstrate how to edit these new password policies to help you meet your security standards by using AWS Microsoft AD. I also introduce the password attributes you can modify and demonstrate how to apply password policies to user groups in your domain.

Prerequisites

The instructions in this post assume that you already have the following components running:

  • An active AWS Microsoft AD directory.
  • An Amazon EC2 for Windows Server instance that is domain joined to your AWS Microsoft AD directory and on which you have installed ADAC.

If you still need to meet these prerequisites before proceeding:

Scenario overview

Let’s say I am the Active Directory (AD) administrator of Example Corp. At Example Corp., we have a group of technical administrators, several groups of senior managers, and general, nontechnical employees. I need to create password policies for these groups that match our security standards.

Our general employees have access only to low-sensitivity information. However, our senior managers regularly access confidential information and we want to enforce password complexity (a mix of upper and lower case letters, numbers, and special characters) to reduce the risk of data theft. For our administrators, we want to enforce password complexity policies to prevent unauthorized access to our system administration tools.

Our security standards call for the following enforced password and account lockout policies:

  • General employees – To make it easier for nontechnical general employees to remember their passwords, we do not enforce password complexity. However, we want to enforce a minimum password length of 8 characters and a lockout policy after 6 failed login attempts as a minimum bar to protect against unwanted access to our low-sensitivity information. If a general employee forgets their password and becomes locked out, we let them try again in 5 minutes, rather than require escalated password resets. We also want general employees to rotate their passwords every 60 days with no duplicated passwords in the past 10 password changes.
  • Senior managers – For senior managers, we enforce a minimum password length of 10 characters and require password complexity. An account lockout is enforced after 6 failed attempts with an account lockout duration of 15 minutes. Senior managers must rotate their passwords every 45 days, and they cannot duplicate passwords from the past 20 changes.
  • Administrators – For administrators, we enforce password complexity with a minimum password length of 15 characters. We also want to lock out accounts after 6 failed attempts, have password rotation every 30 days, and disallow duplicate passwords in the past 30 changes. When a lockout occurs, we require a special administrator to intervene and unlock the account so that we can be aware of any potential hacking.
  • Fine-Grained Password Policy administrators – To ensure that only trusted administrators unlock accounts, we have two special administrator accounts (admin and midas) that can unlock accounts. These two accounts have the same policy as the other administrators except they have an account lockout duration of 15 minutes, rather than requiring a password reset. These two accounts are also the accounts used to manage Example Corp.’s password policies.

The following table summarizes how I edit each of the four policies I intend to use.

Policy name EXAMPLE-PSO-01 EXAMPLE-PSO-02 EXAMPLE-PSO-03 EXAMPLE-PSO-05
Precedence 10 20 30 50
User group Fine-Grained Password Policy Administrators Other Administrators Senior Managers General Employees
Minimum password length 15 15 10 8
Password complexity Enable Enable Enable Disable
Maximum password age 30 days 30 days 45 days 60 days
Account complexity Enable Enable Enable Disable
Number of failed logon attempts allowed 6 6 6 6
Duration 15 minutes Not applicable 15 minutes 5 minutes
Password history 24 30 20 10
Until admin manually unlocks account Not applicable Selected Not applicable Not applicable

To implement these password policies, I use 4 of the 5 new password policies available in AWS Microsoft AD:

  1. I first explain how to configure the password policies.
  2. I then demonstrate how to apply the four password policies that match Example Corp.’s security standards for these user groups.

1. Configure password policies in AWS Microsoft AD

To help you get started with password policies, AWS has added the Fine-Grained Pwd Policy Admins AD security group to your AWS Microsoft AD directory. Any user or other security group that is part of the Fine-Grained Pwd Policy Admins group has permissions to edit and apply the five new password policies. By default, your directory Admin is part of the new group and can add other users or groups to this group.

Adding users to the Fine-Grained Pwd Policy Admins user group

Follow these steps to add more users or AD security groups to the Fine-Grained Pwd Policy Admins security group so that they can administer fine-grained password policies:

  1. Launch ADAC from your managed instance.
  2. Switch to the Tree View and navigate to CORP > Users.
  3. Find the Fine Grained Pwd Policy Admins user group. Add any users or groups in your domain to this group.

Edit password policies

To edit fine-grained password policies, open ADAC from any management instance joined to your domain. Switch to the Tree View and navigate to System > Password Settings Container. You will see the five policies containing the string -PSO- that AWS added to your directory, as shown in the following screenshot. Select a policy to edit it.

Screenshot showing the five new password policies

After editing the password policy, apply the policy by adding users or AD security groups to these policies by choosing Add. The default domain GPO applies if you do not configure any of the five password policies. For additional details about using Password Settings Container, go to Step-by-Step: Enabling and Using Fine-Grained Password Policies in AD on the Microsoft TechNet Blog.

The password attributes you can edit

AWS allows you to edit all of the password attributes except Precedence (I explain more about Precedence in the next section). These attributes include:

  • Password history
  • Minimum password length
  • Minimum password age
  • Maximum password age
  • Store password using reversible encryption
  • Password must meet complexity requirements

You also can enforce the following attributes for account lockout settings:

  • The number of failed login attempts allowed
  • Account lockout duration
  • Reset failed login attempts after a specified duration

For more details about how these attributes affect password enforcement, see AD DS: Fine-Grained Password Policies on Microsoft TechNet.

Understanding password policy precedence

AD password policies have a precedence (a numerical attribute that AD uses to determine the resultant policy) associated with them. Policies with a lower value for Precedence have higher priority than other policies. A user inherits all policies that you apply directly to the user or to any groups to which the user belongs. For example, suppose jsmith is a member of the HR group and also a member of the MANAGERS group. If I apply a policy with a Precedence of 50 to the HR group and a policy with a Precedence of 40 to MANAGERS, the policy with the Precedence value of 40 ranks higher and AD applies that policy to jsmith.

If you apply multiple policies to a user or group, the resultant policy is determined as follows by AD:

  1. If you apply a policy directly to a user, AD enforces the lowest directly applied password policy.
  2. If you did not apply a policy directly to the user, AD enforces the policy with the lowest Precedence value of all policies inherited by the user through the user’s group membership.

For more information about AD fine-grained policies, see AD DS: Fine-Grained Password Policies on Microsoft TechNet.

2. Apply password policies to user groups

In this section, I demonstrate how to apply Example Corp.’s password policies. Except in rare cases, I only apply policies by group membership, which ensures that AD does not enforce a lower priority policy on an individual user if have I added them to a group with a higher priority policy.

Because my directory is new, I use a Remote Desktop Protocol (RDP) connection to sign in to the Windows Server instance I domain joined to my AWS Microsoft AD directory. Signing in with the admin account, I launch ADAC to perform the following tasks:

  1. First, I set up my groups so that I can apply password policies to them. Later, I can create user accounts and add them to my groups and AD applies the right policy by using the policy precedence and resultant policy algorithms I discussed previously. I start by adding the two special administrative accounts (admin and midas) that I described previously to the Fine-Grained Pwd Policy Admins. Because AWS Microsoft AD adds my default admin account to Fine-Grained Pwd Policy Admins, I only need to create midas and then add midas to the Fine-Grained Pwd Policy Admins group.
  2. Next, I create the Other Administrators, Senior Managers, and General Employees groups that I described previously, as shown in the following screenshot.
    Screenshot of the groups created

For this post’s example, I use these four policies:

  1. EXAMPLE-PSO-01 (highest priority policy) – For the administrators who manage Example Corp.’s password policies. Applying this highest priority policy to the Fine-Grained Pwd Policy Admins group prevents these users from being locked out if they also are assigned to a different policy.
  2. EXAMPLE-PSO-02 (the second highest priority policy) – For Example Corp.’s other administrators.
  3. EXAMPLE-PSO-03 (the third highest priority policy) – For Example Corp.’s senior managers.
  4. EXAMPLE-PSO-05 (the lowest priority policy) – For Example Corp.’s general employees.

This leaves me one password policy (EXAMPLE-PSO-04) that I can use for in the future if needed.

I start by editing the policy, EXAMPLE-PSO-01. To edit the policy, I follow the Edit password policies section from earlier in this post. When finished, I add the Fine-Grained Pwd Policy Admins group to that policy, as shown in the following screenshot. I then repeat the process for each of the remaining policies, as described in the Scenario overview section earlier in this post.

Screenshot of adding the Fine-Grained Pwd Policy Admins group to the EXAMPLE-PSO-01 policy

Though AD enforces new password policies, the timing related to how password policies replicate in the directory, the types of attributes that are changed, and the timing of user password changes can cause variability in the immediacy of policy enforcement. In general, after the policies are replicated throughout the directory, attributes that affect account lockout and password age take effect. Attributes that affect the quality of a password, such as password length, take effect when the password is changed. If the password age for a user is in compliance, but their password strength is out of compliance, the user is not forced to change their password. For more information password policy impact, see this Microsoft TechNet article.

Summary

In this post, I have demonstrated how you can configure strong password policies to meet your security standards by using AWS Microsoft AD. To learn more about AWS Microsoft AD, see the AWS Directory Service home page.

If you have comments about this post, submit them in the “Comments” section below. If you have questions about this blog post, start a new thread on the Directory Service forum.

– Ravi

How to Enable the Use of Remote Desktops by Deploying Microsoft Remote Desktop Licensing Manager on AWS Microsoft AD

Post Syndicated from Ron Cully original https://aws.amazon.com/blogs/security/how-to-enable-the-use-of-remote-desktops-by-deploying-microsoft-remote-desktop-licensing-manager-on-aws-microsoft-ad/

AWS Directory Service for Microsoft Active Directory (Enterprise Edition), also known as AWS Microsoft AD, now supports Microsoft Remote Desktop Licensing Manager (RD Licensing). By using AWS Microsoft AD as the directory for your Remote Desktop Services solution, you reduce the time it takes to deploy remote desktop solutions on Amazon EC2 for Windows Server instances, and you enable your users to use remote desktops with the credentials they already know. In this blog post, I explain how to deploy RD Licensing Manager on AWS Microsoft AD to enable your users to sign in to remote desktops by using credentials stored in an AWS Microsoft AD or an on-premises Active Directory (AD) domain.

Enable your AWS Microsoft AD users to open remote desktop sessions

To use RD Licensing, you must authorize RD Licensing servers in the same Active Directory domain as the Windows Remote Desktop Session Hosts (RD Session Hosts) by adding them to the Terminal Service Licensing Server security group in AD. This new release grants your AWS Microsoft AD administrative account permissions to do this. As a result, you can now deploy RD Session Hosts in the AWS Cloud without the extra time and effort to set up and configure your own AD domain on Amazon EC2 for Windows Server.

The following diagram illustrates the steps to set up remote desktops with RD Licensing with users in AWS Microsoft AD and shows what happens when users connect to remote desktops.

Diagram illustrating the steps to set up remote desktops with RD Licensing with users in AWS Microsoft AD

In detail, here is how the process works, as it is illustrated in the preceding diagram:

  1. Create an AWS Microsoft AD directory and create users in the directory. You can add user accounts (in this case jsmith) using Active Directory Users and Computers on an EC2 for Windows Server instance that you joined to the domain.
  2. Create EC2 for Windows Server instances to use as your RD Licensing servers (RDLS1 in the preceding diagram). Add the instances to the same domain to which you will join your Windows Remote Desktop Session Hosts (RD Session Hosts).
  3. Configure your EC2 for Windows Server instances as RD Licensing servers and add them to the Terminal Service Licensing Servers security group in AWS Microsoft AD. You can connect to the instances from the AWS Management Console to configure RD Licensing. You also can use Active Directory Users and Computers to add the RD Licensing servers to the security group, thereby authorizing the instances for RD Licensing.
  4. Install your Remote Desktop Services client access licenses (RDS CALs) on the RD Licensing server. You can connect to the instances from the AWS Management Console to install the RDS CALs.
  5. Create other hosts for use as RD Session Hosts (RDSH1 in the diagram). Add the hosts to the same domain as your RD Licensing servers.
  6. A user (in this case jsmith) attempts to open an RDS session.
  7. The RD Session Host requests an RDS CAL from the RD Licensing Server.
  8. The RD Licensing Server returns an RDS CAL to the RD Session Host.

Because the user exists in AWS Microsoft AD, authentication happens against AWS Microsoft AD. The order of authentication relative to session creation depends on whether you configure your RD Session Host for Network Level Authentication.

Enable your users to open remote desktop sessions with their on-premises credentials

If you have an on-premises AD domain with users, your users can open remote desktop sessions with their on-premises credentials if you create a forest trust from AWS Microsoft AD to your Active Directory. The trust enables using on-premises credentials without the need for complex directory synchronization or replication. The following diagram illustrates how to configure a system using the same steps as in the previous section, except that you must create a one-way trust to your on-premises domain in Step 1a. With the trust in place, AWS Microsoft AD refers the RD Session Host to the on-premises domain for authentication.

Diagram illustrating how to configure a system using the same steps as in the previous section, except that you must create a one-way trust to your on-premises domain in Step 1a

Summary

In this post, I have explained how to authorize RD Licensing in AWS Microsoft AD to support EC2-based remote desktop sessions for AWS managed users and on-premises AD managed users. To learn more about how to use AWS Microsoft AD, see the AWS Directory Service documentation. For general information and pricing, see the AWS Directory Service home page.

If you have comments about this blog post, submit a comment in the “Comments” section below. If you have implementation or troubleshooting questions, please start a new thread on the Directory Service forum.

– Ron