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Description

Ensure that all Keys in Role Based Access Control (RBAC) Azure Key Vaults have an expiration date set.

Rationale​

Azure Key Vault enables users to store and use cryptographic keys within the Microsoft Azure environment. The exp (expiration date) attribute identifies the expiration date on or after which the key MUST NOT be used for encryption of new data, wrapping of new keys, and signing. By default, keys never expire. It is thus recommended that keys be rotated in the key vault and set an explicit expiration date for all keys to help enforce the key rotation. This ensures that the keys cannot be used beyond their assigned lifetimes.

Impact​

Keys cannot be used beyond their assigned expiration dates respectively. Keys need to be rotated periodically wherever they are used.

Audit​

From Azure Portal​

  1. Go to Key vaults.
  2. For each Key vault, click on Keys.
  3. In the main pane, ensure that an appropriate Expiration date is set for any keys that are Enabled.

From Azure CLI​

Get a list of all the key vaults in your Azure environment by running the following command:

az keyvault list

Then for each key vault listed ensure that the output of the below command contains Key ID (kid), enabled status as true and Expiration date (expires) is not empty or null:

az keyvault key list --vault-name <VaultName> --query '[*].{"kid":kid,"enabled":attributes.enabled,"expires":attributes.expires}'

From PowerShell​

Retrieve a list of Azure Key vaults:

Get-AzKeyVault

For each Key vault run the following command to determine which vaults are configured to use RBAC:

Get-AzKeyVault -VaultName <VaultName>

For each Key vault with the EnableRbacAuthorizatoin setting set to True, run the following command:

Get-AzKeyVaultKey -VaultName <VaultName>

Make sure the Expires setting is configured with a value as appropriate wherever the Enabled setting is set to True.

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, keys do not expire.

References​

  1. https://docs.microsoft.com/en-us/azure/key-vault/key-vault-whatis
  2. https://docs.microsoft.com/en-us/rest/api/keyvault/about-keys--secrets-and-certificates#key-vault-keys
  3. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-data-protection#dp-6-use-a-secure-key-management-process
  4. https://docs.microsoft.com/en-us/powershell/module/az.keyvault/set-azkeyvaultkeyattribute?view=azps-0.10.0