Cis Azure Storage 17.2.1

17.2.1 Ensure Private Endpoints are used to access Storage Accounts (Automated)

Description

Use private endpoints for your Azure Storage accounts to allow clients and services to securely access data located over a network via an encrypted Private Link. To do this, the private endpoint uses an IP address from the VNet for each service. Network traffic between disparate services securely traverses encrypted over the VNet. This VNet can also link addressing space, extending your network and accessing resources on it. Similarly, it can be a tunnel through public networks to connect remote infrastructures together. This creates further security through segmenting network traffic and preventing outside sources from accessing it.

Rationale

Securing traffic between services through encryption protects the data from easy interception and reading.

Impact

A Private Endpoint costs approximately US$7.30 per month. If an Azure Virtual Network is not implemented correctly, this may result in the loss of critical network traffic.

Audit Procedure

Audit from Azure Portal

1. Open the Storage Accounts blade.
2. For each listed Storage Account, perform the following check:
3. Under the Security + networking heading, click on Networking.
4. Click on the Private endpoint connections tab at the top of the networking window.
5. Ensure that for each VNet that the Storage Account must be accessed from, a unique Private Endpoint is deployed and the Connection state for each Private Endpoint is Approved.

Repeat the procedure for each Storage Account.

Audit from PowerShell

$storageAccount = Get-AzStorageAccount -ResourceGroup '<ResourceGroupName>' -Name '<storageaccountname>'

Get-AzPrivateEndpoint -ResourceGroup '<ResourceGroupName>'|Where-Object {$_.PrivateLinkServiceConnectionsText -match $storageAccount.id}

If the results of the second command returns information, the Storage Account is using a Private Endpoint and complies with this Benchmark, otherwise if the results of the second command are empty, the Storage Account generates a finding.

Audit from Azure CLI

az storage account show --name '<storage account name>' --query "privateEndpointConnections[0].id"

If the above command returns data, the Storage Account complies with this Benchmark, otherwise if the results are empty, the Storage Account generates a finding.

Audit from Azure Policy

If referencing a digital copy of this Benchmark, clicking a Policy ID will open a link to the associated Policy definition in Azure. If referencing a printed copy, you can search Policy IDs from this URL: https://portal.azure.com/#view/Microsoft_Azure_Policy/PolicyMenuBlade/~/Definitions

• Policy ID: 6edd7eda-6dd8-40f7-810d-67160c639cd9
• Name: 'Storage accounts should use private link'

Expected Result

Each Storage Account has at least one Private Endpoint connection with a Connection state of Approved. The Azure CLI command returns a non-empty Private Endpoint connection ID. The Azure Policy 'Storage accounts should use private link' shows compliant.

Remediation

Remediate from Azure Portal

1. Open the Storage Accounts blade
2. For each listed Storage Account, perform the following:
3. Under the Security + networking heading, click on Networking
4. Click on the Private endpoint connections tab at the top of the networking window
5. Click the + Private endpoint button
6. In the 1 - Basics tab/step:
   • Enter a name that will be easily recognizable as associated with the Storage Account (Note: The "Network Interface Name" will be automatically completed, but you can customize it if needed.)
   • Ensure that the Region matches the region of the Storage Account
   • Click Next
7. In the 2 - Resource tab/step:
   • Select the target sub-resource based on what type of storage resource is being made available
   • Click Next
8. In the 3 - Virtual Network tab/step:
   • Select the Virtual network that your Storage Account will be connecting to
   • Select the Subnet that your Storage Account will be connecting to
   • (Optional) Select other network settings as appropriate for your environment
   • Click Next
9. In the 4 - DNS tab/step:
   • (Optional) Select other DNS settings as appropriate for your environment
   • Click Next
10. In the 5 - Tags tab/step:
    • (Optional) Set any tags that are relevant to your organization
    • Click Next
11. In the 6 - Review + create tab/step:
    • A validation attempt will be made and after a few moments it should indicate Validation Passed - if it does not pass, double-check your settings before beginning more in depth troubleshooting.
    • If validation has passed, click Create then wait for a few minutes for the scripted deployment to complete.

Repeat the above procedure for each Private Endpoint required within every Storage Account.

Remediate from PowerShell

$storageAccount = Get-AzStorageAccount -ResourceGroupName '<ResourceGroupName>' -Name '<storageaccountname>'

$privateEndpointConnection = @{
                            Name = 'connectionName'
                            PrivateLinkServiceId = $storageAccount.Id
                            GroupID = "blob|blob_secondary|file|file_secondary|table|table_secondary|queue|queue_secondary|web|web_secondary|dfs|dfs_secondary"
}

$privateLinkServiceConnection = New-AzPrivateLinkServiceConnection @privateEndpointConnection

$virtualNetDetails = Get-AzVirtualNetwork -ResourceGroupName '<ResourceGroupName>' -Name '<name>'

$privateEndpoint = @{
              ResourceGroupName = '<ResourceGroupName>'
              Name = '<PrivateEndpointName>'
              Location = '<location>'
              Subnet = $virtualNetDetails.Subnets[0]
              PrivateLinkServiceConnection = $privateLinkServiceConnection
}

New-AzPrivateEndpoint @privateEndpoint

Remediate from Azure CLI

az network private-endpoint create --resource-group <ResourceGroupName> --location <location> --name <private endpoint name> --vnet-name <VNET Name> --subnet <subnet name> --private-connection-resource-id <storage account ID> --connection-name <private link service connection name> --group-id <blob|blob_secondary|file|file_secondary|table|table_secondary|queue|queue_secondary|web|web_secondary|dfs|dfs_secondary>

Default Value

By default, Private Endpoints are not created for Storage Accounts.

References

1. https://docs.microsoft.com/en-us/azure/storage/common/storage-private-endpoints
2. https://docs.microsoft.com/en-us/azure/virtual-network/virtual-networks-overview
3. https://docs.microsoft.com/en-us/azure/private-link/create-private-endpoint-portal
4. https://docs.microsoft.com/en-us/azure/private-link/create-private-endpoint-cli?tabs=dynamic-ip
5. https://docs.microsoft.com/en-us/azure/private-link/create-private-endpoint-powershell?tabs=dynamic-ip
6. https://docs.microsoft.com/en-us/azure/private-link/tutorial-private-endpoint-storage-portal
7. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-network-security#ns-2-secure-cloud-native-services-with-network-controls

Additional Information

A NAT gateway is the recommended solution for outbound internet access.

Profile

Level 2 | Automated