Description:

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


Rationale:

The Azure Key Vault enables users to store and keep secrets within the Microsoft Azure environment. Secrets in the Azure Key Vault are octet sequences with a maximum size of 25k bytes each. The exp (expiration date) attribute identifies the expiration date on or

after which the secret MUST NOT be used. By default, secrets never expire. It is thus recommended to rotate secrets in the key vault and set an explicit expiration date for all secrets. This ensures that the secrets cannot be used beyond their assigned lifetimes.


Impact:

Secrets cannot be used beyond their assigned expiry date respectively. Secrets 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 Secrets.

3. In the main pane, ensure that the status of the secret is Enabled.

4. For each enabled secret, ensure that an appropriate Expiration date is set.


From Azure CLI:

Ensure that the output of the below command contains ID (id), enabled status as true and Expiration date (expires) is not empty or null:

az keyvault secret list --vault-name <KEYVAULTNAME> --query

'[*].{"kid":kid,"enabled":attributes.enabled,"expires":attributes.expires}'


From PowerShell:

Retrieve a list of Key vaults:

Get-AzKeyVault

For each Key vault, run the following command to determine which vaults are


configured to use RBAC:

Get-AzKeyVault -VaultName <Vault Name>


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

Get-AzKeyVaultSecret -VaultName <Vault Name>

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


Remediation:

From Azure Portal:

1. Go to Key vaults.

2. For each Key vault, click on Secrets.

3. In the main pane, ensure that the status of the secret is Enabled.

4. For each enabled secret, ensure that an appropriate Expiration date is set.


From Azure CLI:

Update the Expiration date for the secret using the below command:

az keyvault secret set-attributes --name <secretName> --vault-name <vaultName> --expires Y-m-d'T'H:M:S'Z'


Note:

To view the expiration date on all secrets in a Key Vault using Microsoft API, the List Key permission is required.


To update the expiration date for the secrets:

1. Go to the Key vault, click on Access Control (IAM).

2. Click on Add role assignment and assign the role of Key Vault Secrets Officer to the appropriate user.


From PowerShell:



Default Value:

By default, secrets 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-andcertificates#key-vault-secrets

3. https://docs.microsoft.com/en-us/security/benchmark/azure/security-controls-v3- data-protection#dp-6-use-a-secure-key-management-process

4. https://docs.microsoft.com/en-us/powershell/module/az.keyvault/setazkeyvaultsecretattribute?view=azps-0.10.0