secure-your-domain.md

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Secure Azure AD Domain Services | Microsoft Docs'	Learn how to disable weak ciphers, old protocols, and NTLM password hash synchronization for an Azure Active Directory Domain Services managed domain.	active-directory-ds	iainfoulds	daveba	6b4665b5-4324-42ab-82c5-d36c01192c2a	active-directory	domain-services	identity	article	09/09/2019	iainfou

Disable weak ciphers and password hash synchronization to secure an Azure AD Domain Services managed domain

By default, Azure Active Directory Domain Services (Azure AD DS) enables the use of ciphers such as NTLM v1 and TLS v1. These ciphers may be required for some legacy applications, but are considered weak and can be disabled if you don't need them. If you have on-premises hybrid connectivity using Azure AD Connect, you can also disable the synchronization of NTLM password hashes.

This article shows you how to disable NTLM v1 and TLS v1 ciphers and disable NTLM password hash synchronization.

Prerequisites

To complete this article, you need the following resources:

• An active Azure subscription.
  • If you don’t have an Azure subscription, create an account.
• An Azure Active Directory tenant associated with your subscription, either synchronized with an on-premises directory or a cloud-only directory.
  • If needed, create an Azure Active Directory tenant or associate an Azure subscription with your account.
• An Azure Active Directory Domain Services managed domain enabled and configured in your Azure AD tenant.
  • If needed, create and configure an Azure Active Directory Domain Services instance.
• Install and configure Azure PowerShell.
  • If needed, follow the instructions to install the Azure PowerShell module and connect to your Azure subscription.
  • Make sure that you sign in to your Azure subscription using the Connect-AzAccount cmdlet.
• Install and configure Azure AD PowerShell.
  • If needed, follow the instructions to install the Azure AD PowerShell module and connect to Azure AD.
  • Make sure that you sign in to your Azure AD tenant using the Connect-AzureAD cmdlet.

Disable weak ciphers and NTLM password hash sync

To disable weak cipher suites and NTLM credential hash synchronization, sign in to your Azure account, then get the Azure AD DS resource using the Get-AzResource cmdlet:

Tip

If you receive an error using the Get-AzResource command that the Microsoft.AAD/DomainServices resource doesn't exist, elevate your access to manage all Azure subscriptions and management groups.

Login-AzAccount

$DomainServicesResource = Get-AzResource -ResourceType "Microsoft.AAD/DomainServices"

Next, define DomainSecuritySettings to configure the following security options:

1. Disable NTLM v1 support.
2. Disable the synchronization of NTLM password hashes from your on-premises AD.
3. Disable TLS v1.

Important

Users and service accounts can't perform LDAP simple binds if you disable NTLM password hash synchronization in the Azure AD DS managed domain. If you need to perform LDAP simple binds, don't set the "SyncNtlmPasswords"="Disabled"; security configuration option in the following command.

$securitySettings = @{"DomainSecuritySettings"=@{"NtlmV1"="Disabled";"SyncNtlmPasswords"="Disabled";"TlsV1"="Disabled"}}

Finally, apply the defined security settings to the Azure AD DS managed domain using the Set-AzResource cmdlet. Specify the Azure AD DS resource from the first step, and the security settings from the previous step.

Set-AzResource -Id $DomainServicesResource.ResourceId -Properties $securitySettings -Verbose -Force

It takes a few moments for the security settings to be applied to the Azure AD DS managed domain.

Next steps

To learn more about the synchronization process, see How objects and credentials are synchronized in an Azure AD DS managed domain.