Description: 

Expiration Date for secrets in Azure Key Vault ensures that secrets are automatically marked as expired after a specified period, helping to enforce a lifecycle for secret management. For RBAC-enabled Key Vaults, where access control is based on Azure Role-Based Access Control (RBAC), it’s crucial to ensure that all secrets have expiration dates set to meet security and compliance standards.

When the expiration date is set for secrets, Azure Key Vault will automatically handle their lifecycle and enforce secure expiration. This reduces the manual overhead of managing secret lifetimes and ensures that secrets are periodically rotated or revoked.

Rationale:

Setting an expiration date for secrets is a key practice for managing secrets effectively. It ensures that secrets are periodically refreshed, preventing the risks associated with using stale or expired credentials. By automating the expiration dates for secrets in RBAC-enabled Key Vaults, organizations can better control access to sensitive data, comply with regulatory requirements, and enforce key management best practices. This is especially critical for meeting compliance frameworks like SOC 2, HIPAA, and GDPR.

Impact:

Automatically setting expiration dates for secrets ensures the security of Azure Key Vault by making sure secrets are valid only for a predefined period. This reduces the possibility of using outdated credentials and prevents the risk of exposed secrets. However, this also introduces the need to monitor and rotate secrets before they expire to prevent service disruptions. It's essential that applications and users are aware of the expiration to update their secrets when needed.

Default Value:

By default, expiration dates are not set for secrets in Azure Key Vaults (whether RBAC-enabled or not). This must be explicitly configured for each secret or via automation.

Pre-requisites:

  • Azure Key Vault (RBAC-enabled): Ensure the Key Vault is configured with Role-Based Access Control (RBAC) and that secrets are stored.

  • Permissions: You need appropriate permissions, such as Owner or Contributor role, to modify secrets and access their configuration in the Azure Key Vault.

  • Expiration Date Configuration: Ensure that policies or automation are in place to set expiration dates for all secrets.

Remediation:

Audit:

To check if expiration dates are set for all secrets in an RBAC-enabled Key Vault:

  1. Sign in to the Azure portal using an account with appropriate permissions.

  2. Navigate to the Azure Key Vault:

    • In the Azure portal, go to Key Vaults and select the relevant Key Vault.

  3. Check Secrets:

    • In the Key Vault dashboard, click on Secrets under Settings.

    • For each secret, verify that an Expiration Date is set. If expiration dates are missing, secrets should be updated to include them.

Automated Implementation:

To ensure that expiration dates are set for all secrets in RBAC-enabled Key Vaults, you can use Azure Automation or Azure Logic Apps to enforce this.

  1. Automate Expiration Date Assignment using Azure Automation or Azure Logic Apps:

    • You can create an Azure Automation runbook or Logic App to periodically check the secrets in Key Vault and set or update their expiration dates.

    • Example of an Azure Logic App flow:

      1. Get secrets from Key Vault.

      2. For each secret, set expiration date (e.g., 90 days from creation or last update).

      3. Update the secret metadata in Azure Key Vault.

  2. Alternatively, you can use Azure CLI or Azure SDKs to automate the process.

Set Expiration Date via Azure CLI: You can use the Azure CLI to set expiration dates for secrets:

az keyvault secret set --vault-name <YourKeyVaultName> --name <SecretName> --value <SecretValue> --expires <ExpirationDate>

 Example:

az keyvault secret set --vault-name "MyKeyVault" --name "MySecret" --value "MySecretValue" --expires "2023-12-31T00:00:00Z"


  1. Create an Azure Automation Runbook:

    • Use Azure Automation to create a runbook that periodically sets expiration dates for all secrets within RBAC-enabled Key Vaults.

    • The script can be written in PowerShell or Python and scheduled to run periodically.

Backout Plan:

To disable expiration dates for secrets (not recommended from a security perspective):

  1. Sign in to the Azure portal with appropriate permissions.

  2. Navigate to the Azure Key Vault:

    • Go to Key Vaults in the Azure portal and select the relevant Key Vault.

  3. Go to Secrets:

    • In the Settings section, click on Secrets.

  4. Update Secret:

    • For each secret, remove the expiration date or change it to a longer duration if needed.

If automation was applied through Azure Logic Apps or Azure Automation, you can disable the runbook or Logic App.

References: