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Description

Enable AuditEvent logging for key vault instances to ensure interactions with key vaults are logged and available.

Rationale​

Monitoring how and when key vaults are accessed, and by whom, enables an audit trail of interactions with confidential information, keys, and certificates managed by Azure Key Vault. Enabling logging for Key Vault saves information in a user provided destination of either an Azure storage account or Log Analytics workspace. The same destination can be used for collecting logs for multiple Key Vaults.

Audit​

From Azure Portal​

  1. Go to Key vaults.
  2. For each Key vault, under Monitoring, go to Diagnostic settings.
  3. Click Edit setting next to a diagnostic setting.
  4. Ensure that a destination is configured.
  5. Under Category groups, ensure that audit and allLogs are checked.

From Azure CLI​

List all key vaults:

az keyvault list

For each keyvault id:

az monitor diagnostic-settings list --resource <id>

Ensure that storageAccountId reflects your desired destination and that categoryGroup and enabled are set as follows in the sample outputs below:

"logs": [ 
    { 
        "categoryGroup": "audit", 
        "enabled": true, 
    }, 
    { 
        "categoryGroup": "allLogs", 
        "enabled": true, 
    }
]

From PowerShell​

List the key vault(s) in the subscription:

Get-AzKeyVault

For each key vault, run the following:

Get-AzDiagnosticSetting -ResourceId <key_vault_id>

Ensure that StorageAccountId, ServiceBusRuleId, MarketplacePartnerId, or WorkspaceId is set as appropriate. Also, ensure that enabled is set to true, and that categoryGroup reflects both audit and allLogs category groups.

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.

Default Value​

By default, Diagnostic AuditEvent logging is not enabled for Key Vault instances.

References​

  1. https://docs.microsoft.com/en-us/azure/key-vault/general/howto-logging
  2. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-data-protection#dp-8-ensure-security-of-key-and-certificate-repository
  3. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-logging-threat-detection#lt-3-enable-logging-for-security-investigation

Additional Information​

DEPRECATION WARNING

Retention rules for Key Vault logging is being migrated to Azure Storage Lifecycle Management. Retention rules should be set based on the needs of your organization and security or compliance frameworks. Please visit https://learn.microsoft.com/en-us/azure/azure-monitor/essentials/migrate-to-azure-storage-lifecycle-policy?tabs=portal for detail on migrating your retention rules.

Microsoft has provided the following deprecation timeline:

March 31, 2023 – The Diagnostic Settings Storage Retention feature will no longer be available to configure new retention rules for log data. This includes using the portal, CLI PowerShell, and ARM and Bicep templates. If you have configured retention settings, you'll still be able to see and change them in the portal.

March 31, 2024 – You will no longer be able to use the API (CLI, Powershell, or templates), or Azure portal to configure retention setting unless you're changing them to 0. Existing retention rules will still be respected.

September 30, 2025 – All retention functionality for the Diagnostic Settings Storage Retention feature will be disabled across all environments.