SmartStore on Azure Blob security strategies
SmartStore security strategies vary according to the type of remote storage service. This topic covers security when using Azure Blob storage as the remote storage service.
Authenticate with the remote storage service
The best practice is to authenticate through Azure Active Directory using managed identities. Authorizing access with Azure Active Directory provides superior security and ease of use over other authorization options.
SmartStore on Azure Blob supports the following managed-identity-based authentication methods:
- Authentication through system-assigned managed identity assigned to the Azure Virtual Machine that the indexer instance is running on.
- Authentication through user-assigned managed identity using the registered application's client secret.
The client secret method is configured in each indexer's
remote.azure.tenant_id: The ID of the tenant. The tenant is an instance of an Azure AD directory. Check your Azure subscription for details.
remote.azure.client_id: The ID of the client. This ID is also known as the application ID, the unique identifier that Azure AD issues to an application registration. The ID identifies a specific application and its associated configurations. You can obtain the client ID for an application from the Azure Portal in the Overview section for the registered application.
remote.azure.client_secret: The secret key to use when authenticating through the client secret method. You generate the secret key through the Azure Portal.
For more information on these settings, see the indexes.conf spec file.
Appropriate access policies and permissions need to be assigned to the security principal to allow access to the Azure container.
Caution: You can also use access/secret keys authentication. This method has security implications, but it might be appropriate for smaller or test deployments, depending on your needs. For more information on this method, see the entries for
remote.azure.endpoint in the indexes.conf spec file.
Manage SSL certifications for the remote store
The SSL certification settings vary according to the remote storage service type. This section provides information for managing SSL for an Azure Blob remote store, using the settings provided in
indexes.conf. For more details on any of these settings, as well as for information on additional Azure-related SSL settings, see the indexes.conf spec file.
The Azure SSL settings are overlaid on the
sslConfig stanza in
cipherSuite.Therefore, if you run into issues, consult the
server.conf SSL settings, in addition to the remote-storage-specific settings.
Specify SSL settings on a per-remote-volume basis.
The following table includes common attributes and their recommended values.
|SSL setting||Description||Recommended value|
||Specifies whether to check the server certificate provided by the Azure endpoint.||true|
||Specifies whether to verify that either the Common Name or Subject Alternate Name in the server certificate matches the hostname in the URL it connects to.||true|
||Specifies the minimum SSL/TLS version to use for outgoing connections.||tls1.2|
||Absolute path to the PEM format file containing list of root certificates.||N/A|
||Ciphers to use to connect with Azure Blob storage.||Check with your security experts. Here is an example of the type of value to enter for this attribute:
Encrypt the data on the remote store
SmartStore supports server-side encryption of data-at-rest on Azure Blob storage. SmartStore supports two encryption schemes through the
remote.azure.encryption attribute in
remote.azure.encryption = azure-sse-kv | azure-sse-ms
Configure this attribute on a per-volume basis.
Choosing the encryption method is a one-time decision. You cannot change the encryption method later.
These encryption schemes let you choose between Microsoft-managed keys or customer-managed keys fully configured on the Azure Blob storage account side (transparent from Splunk Enterprise point-of-view)
The default is "azure-sse-ms". (Microsoft-managed keys).
For details on encryption modes, see:
- The indexes.conf spec file for the
- The Azure documentation on configuring Azure Blob storage encryption keys.
Encryption with azure-sse-ms
Here is an example of setting server-side encryption with Microsoft-managed encryption keys:
[volume:azure_storage_ms_keys] storageType = remote path = azure://my/msencrypted/storage remote.azure.encryption = azure-sse-ms
Encryption with azure-sse-kv
Customer-managed keys require an encryption scope. To create an encryption scope, use either keys kept in a key vault or the Microsoft-managed keys.
Encryption scope must be already configured in the storage account before you can enable azure-sse-kv.
Here is an example of setting server-side encryption with customer-supplied encryption keys:
[volume:azure_storage_kv_keys] storageType = remote path = azure://my/cmencrypted/storage remote.azure.encryption = azure-sse-kv remote.azure.azure-sse-kv.encryptionScope = customer_key_scope_1
SmartStore on GCS security strategies
Deploy SmartStore on a new indexer cluster
This documentation applies to the following versions of Splunk® Enterprise: 9.0.0, 9.0.1, 9.0.2, 9.0.3