Cis Azure Foundations 6.1.1.4

Ensure that logging for Azure Key Vault is 'Enabled'

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.

Impact

None identified.

Audit Procedure

Using 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.

Using 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:

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

Using 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.

Expected Result

All Key Vault instances should have diagnostic logging enabled with both audit and allLogs category groups sending to an appropriate destination.

Remediation

Remediate from Azure Portal

1. Go to Key vaults.
2. Select a Key vault.
3. Under Monitoring, select Diagnostic settings.
4. Click Edit setting to update an existing diagnostic setting, or Add diagnostic setting to create a new one.
5. If creating a new diagnostic setting, provide a name.
6. Configure an appropriate destination.
7. Under Category groups, check audit and allLogs.
8. Click Save.

Remediate from Azure CLI

To create a new Diagnostic Settings:

az monitor diagnostic-settings create --name "<diagnostic_setting_name>" --resource <key_vault_id> --logs "[{category:audit,enabled:true},{category:allLogs,enabled:true}]" --metrics "[{category:AllMetrics,enabled:true}]" <[--event-hub <event_hub_ID> --event-hub-rule <event_hub_auth_rule_ID> | --storage-account <storage_account_ID> | --workspace <log_analytics_workspace_ID> | --marketplace-partner-id <solution_resource_ID>]>

Remediate from PowerShell

Create the Log settings object:

$logSettings = @()
$logSettings += New-AzDiagnosticSettingLogSettingsObject -Enabled $true -Category audit
$logSettings += New-AzDiagnosticSettingLogSettingsObject -Enabled $true -Category allLogs

Create the Metric settings object:

$metricSettings = @()
$metricSettings += New-AzDiagnosticSettingMetricSettingsObject -Enabled $true -Category AllMetrics

Create the Diagnostic Settings for each Key Vault:

New-AzDiagnosticSetting -Name "<diagnostic_setting_name>" -ResourceId <key_vault_id> -Log $logSettings -Metric $metricSettings [-StorageAccountId <storage_account_ID> | -EventHubName <event_hub_name> -EventHubAuthorizationRuleId <event_hub_auth_rule_ID> | -WorkSpaceId <log analytics workspace ID> | -MarketPlacePartnerId <full resource ID for third-party solution>]

Default Value

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

References

1. https://learn.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

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