Implementing Azure Files Kerberos for Secure File Sharing

To implement Azure Files Kerberos, you'll need to create a Service Principal in Azure Active Directory (AAD). This is the first step in enabling Kerberos authentication for Azure Files.

With Kerberos, users can access Azure Files without needing to enter their credentials. This is because Kerberos uses ticket-based authentication, which is more secure than traditional username and password combinations.

To enable Kerberos, you'll need to obtain a Kerberos ticket for the user. This is done by using the kinit command, which requests a ticket from the Key Distribution Center (KDC).

The KDC is responsible for issuing and managing Kerberos tickets. It's a critical component of the Kerberos protocol, and it plays a key role in secure authentication.

Azure Files supports the use of a Kerberos ticket to authenticate users. This allows users to access Azure Files without needing to enter their credentials, making it a more secure option.

Worth a look: Azure Auth Json Website Azure Ad Authentication

Before you start using Azure Files Kerberos, you need to ensure your operating system and domain meet certain prerequisites.

To enable Microsoft Entra Kerberos authentication over SMB for Azure file shares, you'll need to have Windows 11 Enterprise/Pro single or multi-session installed on your client machines.

Windows 10 Enterprise/Pro single or multi-session, versions 2004 or later with the latest cumulative updates installed, are also supported. Make sure you've got the KB5007253 - 2021-11 Cumulative Update Preview for Windows 10 installed.

Additionally, Windows Server, version 2022 with the latest cumulative updates installed, especially the KB5007254 - 2021-11 Cumulative Update Preview for Microsoft server operating system version 21H2, is required.

Here are the supported operating systems in a quick reference list:

All client machines must be Microsoft Entra joined or Microsoft Entra hybrid joined. They cannot be joined to Microsoft Entra Domain Services or joined to AD only.

To enable Azure AD Kerberos authentication on Azure Files, you need to configure Azure Files in the storage account. This includes setting up the Active Directory source that contains the user accounts that will access a share in that storage account.

To start, you need to open the Azure portal and navigate to Storage accounts. On the Storage accounts page, select the storage account that should be enabled for Azure AD Kerberos authentication and navigate to File shares.

Here are the five steps to enable Azure AD Kerberos authentication on Azure files:

Make sure to specify the optional domain name and domain GUID for the on-premises AD, to enable the configuring of file and folder level permissions through Windows File Explorer.

Now that you've set up Azure Files Kerberos, it's time to put it to use. Mount an Azure file share to access your files from anywhere.

To do this, you'll need to follow the steps outlined in the Azure documentation. Don't worry, it's a straightforward process.

However, if you're experiencing issues, be aware that there are potential errors when enabling Microsoft Entra Kerberos authentication for hybrid users. Make sure to check the Azure documentation for troubleshooting tips.

Take a look at this: Azure Ad Kerberos

Once you've mounted your Azure file share, you can create a profile container with Azure Files and Microsoft Entra ID. This will allow you to manage your user profiles and settings in a centralized way.

Here's a quick rundown of the next steps to consider:

Azure Files Authentication is a crucial aspect of using Azure Files with Kerberos. You can enable Microsoft Entra Kerberos authentication on Azure Files for hybrid user accounts using the Azure portal, PowerShell, or Azure CLI.

To enable Microsoft Entra Kerberos authentication using the Azure portal, you need to sign in to the Azure portal and select the storage account you want to enable Microsoft Entra Kerberos authentication for. Then, under Data storage, select File shares and next to Active Directory, select the configuration status.

The Azure portal provides a step-by-step guide to enable Microsoft Entra Kerberos authentication, which includes selecting the Microsoft Entra Kerberos checkbox and specifying the domain name and domain GUID for your on-premises AD, if desired.

Alternatively, you can use Azure PowerShell or Azure CLI to enable Microsoft Entra Kerberos authentication. For Azure PowerShell, you need to run a command that includes the storage account name, resource group, and domain name and domain GUID, if specified.

Azure CLI also provides a command to enable Microsoft Entra Kerberos authentication, which includes specifying the storage account name, resource group, and domain name and domain GUID, if specified.

It's worth noting that if you've previously enabled Microsoft Entra Kerberos authentication through manual limited preview steps, the password for the storage account's service principal may expire every six months, preventing users from getting Kerberos tickets to the file share.

Here are the three methods to enable Microsoft Entra Kerberos authentication:

Each method has its own requirements and steps, but they all ultimately enable Microsoft Entra Kerberos authentication on Azure Files for hybrid user accounts.

Azure Files is a fully managed file share service that allows you to access and share files across your applications and services.

For your interest: Azure File Share Tiering

You can mount Azure Files as a drive on your Windows or Linux machine, and access your files from there.

Azure Files supports a wide range of protocols, including SMB 2.1 and later, and it's also compatible with your existing on-premises file servers.

It's a great option for developers, as it provides a simple and consistent way to access and share files across different environments.

Azure Files has a background history that's worth understanding.

The history of Azure Files dates back to a specific point in time, but I can only provide a brief overview.

To provide some context, Azure Files is a service that allows you to store and share files in the cloud.

It was first introduced as a way to provide a scalable and secure solution for storing files in the cloud.

Note: For further information on the points mentioned, links are provided in each case for further reading.

Kerberos support was also introduced to help improve security for Azure Files users.

Kerberos is a security protocol that allows users to access resources over a network without having to enter their credentials each time.

This was a significant development in the history of Azure Files, as it improved the overall security and usability of the service.

Azure Files Support is now more secure and flexible than ever. On August 30, 2022, Microsoft announced Azure AD Kerberos Support for Azure Files Identity-based Authentication.

This preview feature combines Azure AD Kerberos Support with Azure Files to allow Azure AD identified users to connect to Azure Fileshares without any line of sight to the classic domain.

Azure AD joined (AAD join) or hybrid joined (hybrid join) clients are required for this feature to work, eliminating the need for a classic domain connection.

User accounts still need to be synchronized, even with this new feature.

Microsoft provides a video guide on how to enable Azure AD Kerberos for Azure Files in just a few steps.

The Azure Files and Azure AD cloud story continues to evolve, offering more options for secure and seamless file sharing.

SMB Port Blocking is a major hurdle, as many ISPs block the SMB port (445) by default, making it difficult to access Azure Files via the Internet in today's mobile world.

This means you'll usually need to set up a VPN to connect to Azure Files, which can be a bit of a hassle.

Only synchronized users can access the fileshare at this time, which means users existing in the cloud (cloud only) cannot access it.

This is due to Azure AD's inability to issue full-fledged Kerberos ticket-granting tickets (TGTs), but only partial ones.

An existing Active Directory environment is still mandatory, preventing the true cloud only file server.

Microsoft is working to remove these restrictions, but no timeline has been announced.