Use Private Endpoints for Azure Cosmos DB Accounts

Risk Level: High (not acceptable risk)

Ensure that private endpoints are configured for Microsoft Azure Cosmos DB accounts in order to allow clients and services to securely access data located over a network via an encrypted Azure Private Link connection.

Security

Using private endpoints for Microsoft Azure Cosmos DB accounts enables secure data access over Azure Private Link. The private endpoint uses an IP address from the virtual network, ensuring traffic stays within the Microsoft Azure backbone network, avoiding public Internet exposure. This configuration blocks public endpoint connections, enhances virtual network security, and prevents data exfiltration. Additionally, it helps maintain compliance with regulatory requirements and organizational policies by enforcing strict network access controls and minimizing the surface area for potential security breaches.

Audit

To determine if network access to Azure Cosmos DB accounts is allowed via private endpoints only, perform the following operations:

Using Azure Portal

01 Sign in to the Microsoft Azure Portal.

02 Navigate to All resources blade available at https://portal.azure.com/#browse/all to access all your Microsoft Azure cloud resources.

03 Choose the Azure subscription that you want to access from the Subscription equalls all filter box and choose Apply.

04 From the Type equals all filter box, select Type for Filter, Equals for Operator, and Azure Cosmos DB account for Value, then choose Apply to list the Azure Cosmos DB accounts available in the selected subscription.

05 Click on the name (link) of the Azure Cosmos DB account that you want to examine.

06 In the resource navigation panel, under Settings, select Networking to access the networking configuration settings available for the selected DB account.

07 Select the Public access tab and check the Public network access configuration setting to determine the level of access configured for the selected Cosmos DB account. If Public network access is set to Disabled, network access via public endpoints or selected networks is disabled, therefore, you can continue the Audit process with the next step. Otherwise, the Audit process stops here.

08 Select the Private access tab and check for any private endpoints configured for your Cosmos DB account. If there are no private endpoints available on this page, the selected Microsoft Azure Cosmos DB account is not configured to allow network access via private endpoints only.

09 Repeat steps no. 5 – 8 for each Azure Cosmos DB account available in the selected subscription.

10 Repeat steps no. 3 – 9 for each Azure subscription created within your Microsoft Azure cloud account.

Using Azure CLI

01 Run account list command (Windows/macOS/Linux) with custom output filters to list the IDs of the cloud subscriptions available in your Azure cloud account:

az account list
	--query '[*].id'

02 The command output should return the requested subscription identifiers (IDs):

[
	"abcdabcd-1234-abcd-1234-abcdabcdabcd",
	"abcd1234-abcd-1234-abcd-abcd1234abcd"
]

03 Run account set command (Windows/macOS/Linux) with the ID of the Azure cloud subscription that you want to examine as the identifier parameter to set the selected subscription to be the current active subscription (the command does not produce an output):

az account set
	--subscription abcdabcd-1234-abcd-1234-abcdabcdabcd

04 Run cosmosdb list command (Windows/macOS/Linux) with custom output filters to list the ID of each Azure Cosmos DB account available in the selected subscription:

az cosmosdb list
	--query '[*].id'

05 The command output should return the requested Azure Cosmos DB account IDs:

[
	"/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database",
	"/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-cosmos-prod-dba-account"
]

06 Run cosmosdb show command (Windows/macOS/Linux) with the name of the Azure Cosmos DB account that you want to examine as the identifier parameter and custom output filters to determine if the public network access to the selected Cosmos DB account is disabled:

az cosmosdb show
	--ids "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database"
	--query '{publicNetworkAccess:publicNetworkAccess}'

07 The command output should return the status of the "publicNetworkAccess" setting configured for the selected resource:

{
	"publicNetworkAccess": "Disabled"
}

If the command output returns "Disabled" for "publicNetworkAccess", as shown in the example above, network access via public endpoints or selected networks is disabled, therefore, you can continue the Audit process with the next step. Otherwise, the Audit process stops here.

08 Run cosmosdb show command (Windows/macOS/Linux) to describe the private endpoint connections configured for the selected Azure Cosmos DB account:

az cosmosdb show
	--ids "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database"
	--query '{"privateEndpointConnections":privateEndpointConnections}'

09 The command output should return the information available for the configured private endpoints:

{
	"privateEndpointConnections": null
}

If the cosmosdb show command output returns null for the "privateEndpointConnections" attribute value, there are no private endpoint connections associated with your cloud resource, therefore, the selected Microsoft Azure Cosmos DB account is not configured to allow network access via private endpoints only.

10 Repeat steps no. 6 - 9 for each Azure Cosmos DB account available within the selected Azure subscription.

11 Repeat steps no. 3 – 10 for each Azure subscription created in your Microsoft Azure cloud account.

Remediation / Resolution

To ensure that your Microsoft Azure Cosmos DB accounts are accessed exclusively through private endpoint connections, perform the following operations:

Using Azure Portal

01 Sign in to the Microsoft Azure Portal.

02 Navigate to All resources blade available at https://portal.azure.com/#browse/all to access all your Microsoft Azure cloud resources.

03 Choose the Azure subscription that you want to access from the Subscription equalls all filter box and choose Apply.

05 Click on the name (link) of the Azure Cosmos DB account that you want to configure.

06 In the resource navigation panel, under Settings, select Networking to access the networking configuration settings available for the selected DB account.

07 Select the Public access tab, set the Public network access to Disabled, and choose Save to apply the changes. Once the network configuration is updated, no networks can access your resource. Private endpoint connections will be the exclusive way to access your Azure Cosmos DB account.

08 Select the Private access tab, choose Private endpoint, and perform the following actions to create a new private endpoint:

For Basics, provide the following information:
1. For Subscription, choose your Azure subscription.
2. For Resource group, select the correct resource group.
3. Provide a unique name for the private endpoint instance in the Name box.
4. For Region, select the Azure cloud region where the private endpoint instance will be deployed. Your private endpoint must be in the same region as your virtual network (VNet).
5. Choose Next : Resource > to continue the setup process.
For Resource, perform the following actions:
1. For Connection method, choose Connect to an Azure resource in my directory.
2. For Subscription, choose your Azure subscription.
3. For Resource type, select Microsoft.AzureCosmosDB/databaseAccounts.
4. For Resource, choose the name of your Cosmos DB account.
5. For Target sub-resource, select Sql.
6. Choose Next : Virtual Network > to continue the setup.
For Virtual Network, perform the following operations:
1. For Virtual network, choose the name of the Azure virtual network (VNet) that you want to use for your private endpoint.
2. For Subnet, select the VNet subnet where the private endpoint will be deployed.
3. (Optional) For Network policy for private endpoints, choose (edit) next to Disabled to configure network policies for the selected VNet subnet.
4. For Private IP configuration, choose whether to dynamically or statically allocate the private IP address.
5. (Optional) For Application security group, choose Create to create an Application Security Group (ASG) if required. ASGs allow you to configure network security by grouping Azure resources and defining policies based on these groups.
6. Choose Next : DNS > to continue.
For DNS, select Yes for Integrate with private DNS zone under Private DNS integration, to integrate your private endpoint with a private DNS zone. Ensure that the correct subscription and resource group are selected for the private DNS zone. Choose Next : Tags > to continue the setup.
For Tags, use the Name, Value, and Resource fields to create tags that will help organize the identity of the selected resource. Choose Next : Review + create > to validate the private endpoint setup.
For Review + create, review the resource configuration details, then choose Create to create your new private endpoint.

09 Repeat steps no. 5 – 8 for each Azure Cosmos DB account that you want to configure, available in the selected subscription.

10 Repeat steps no. 3 – 9 for each Azure subscription created within your Microsoft Azure cloud account.

Using Azure CLI

01 Run account list command (Windows/macOS/Linux) with custom output filters to list the IDs of the cloud subscriptions available in your Azure cloud account:

az account list
	--query '[*].id'

02 The command output should return the requested subscription identifiers (IDs):

[
	"abcdabcd-1234-abcd-1234-abcdabcdabcd",
	"abcd1234-abcd-1234-abcd-abcd1234abcd"
]

az account set
	--subscription abcdabcd-1234-abcd-1234-abcdabcdabcd

04 Run cosmosdb update command (OSX/Linux/UNIX) with the ID of the Azure Cosmos DB account that you want to configure as the identifier parameter, to disable network access to the selected Cosmos DB account. Once the network configuration changes are applied, no networks can access your resource. Private endpoint connections will be the exclusive way to access your Azure Cosmos DB account:

az cosmosdb update
	--ids "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database"
	--public-network-access DISABLED
	--query '{publicNetworkAccess:publicNetworkAccess}'

05 The command output should return the "publicNetworkAccess" setting status for the selected Cosmos DB account:

{
	"publicNetworkAccess": "Disabled"
}

06 Run network private-endpoint create command (Windows/macOS/Linux) to create and attach a private endpoint to your Microsoft Azure Key Vault. Use the --private-connection-resource-id command parameter to specify the Key Vault resource ID returned at the previous step:

az network private-endpoint create
	--name cc-private-endpoint
	--resource-group cloud-shell-storage-westeurope
	--vnet-name cc-project5-vnet
	--subnet cc-vnet-subnet-001
	--private-connection-resource-id "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database"
	--connection-name cc-project5-cosmosdb-private-connection
	--group-id Sql
	--location westeurope

07 The command output should return the configuration information for your new private endpoint:

{
	"customDnsConfigs": [
		{
			"fqdn": "cc-project5-key-vault.vault.azure.net",
			"ipAddresses": [
				"10.0.0.9"
			]
		}
	],
	"customNetworkInterfaceName": "",
	"id": "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.Network/privateEndpoints/cc-private-endpoint",
	"ipConfigurations": [],
	"location": "westeurope",
	"manualPrivateLinkServiceConnections": [],
	"name": "cc-private-endpoint",
	"networkInterfaces": [
		{
			"id": "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.Network/networkInterfaces/cc-private-endpoint.nic.abcdabcd-1234-abcd-1234-abcdabcdabcd",
			"resourceGroup": "cloud-shell-storage-westeurope"
		}
	],
	"privateLinkServiceConnections": [
		{
			"groupIds": [
				"vault"
			],
			"id": "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.Network/privateEndpoints/cc-private-endpoint/privateLinkServiceConnections/cc-project5-cosmosdb-private-connection",
			"name": "cc-project5-cosmosdb-private-connection",
			"privateLinkServiceConnectionState": {
				"actionsRequired": "None",
				"description": "",
				"status": "Approved"
			},
			"privateLinkServiceId": "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.DocumentDB/databaseAccounts/cc-project5-cosmos-database",
			"provisioningState": "Succeeded",
			"resourceGroup": "cloud-shell-storage-westeurope",
			"type": "Microsoft.Network/privateEndpoints/privateLinkServiceConnections"
		}
	],
	"provisioningState": "Succeeded",
	"resourceGroup": "cloud-shell-storage-westeurope",
	"subnet": {
		"id": "/subscriptions/abcdabcd-1234-abcd-1234-abcdabcdabcd/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.Network/virtualNetworks/cc-project5-vnet/subnets/cc-vnet-subnet-001",
		"resourceGroup": "cloud-shell-storage-westeurope"
	},
	"type": "Microsoft.Network/privateEndpoints"
}

08 Repeat steps no. 4 - 7 for each Azure Cosmos DB account that you want to configure, available within the selected subscription.

09 Repeat steps no. 3 – 8 for each Azure subscription created within your Microsoft Azure cloud account.

References

Azure Official Documentation
Configure Azure Private Link for an Azure Cosmos DB account
Azure Private Endpoint private DNS zone values

Azure Command Line Interface (CLI) Documentation
az account list
az account set
az cosmosdb list
az cosmosdb show
az cosmosdb update
az network private-endpoint create

Publication date May 28, 2025

Audit

Using Azure Portal

Using Azure CLI

Remediation / Resolution

Using Azure Portal

Using Azure CLI

References

Related CosmosDB rules