Cis Azure Compute 2.5

Ensure Azure Key Vaults are Used to Store Secrets

Description

Azure Key Vault will store multiple types of sensitive information such as encryption keys, certificate thumbprints, and Managed Identity Credentials. Access to these 'Secrets' can be controlled through granular permissions.

Rationale

The credentials given to an application have permissions to create, delete, or modify data stored within the systems they access. If these credentials are stored within the application itself, anyone with access to the application or a copy of the code has access to them. Storing within Azure Key Vault as secrets increases security by controlling access. This also allows for updates of the credentials without redeploying the entire application.

Impact

Integrating references to secrets within the key vault are required to be specifically integrated within the application code. This will require additional configuration to be made during the writing of an application, or refactoring of an already written one. There are also additional costs that are charged per 10000 requests to the Key Vault.

Audit Procedure

Using Azure Portal

1. Login to Azure Portal.
2. In the expandable menu on the left go to Key Vaults.
3. View the Key Vaults listed.

Using Azure CLI

To list key vaults and/or HSMs within a subscription run the following command:

az keyvault list [--resource-type] --subscription <id_or_name_of_target_subscription>

--resource-type could be either __vault__ or __hsm__. When parameter is missing all types of vaults will be listed.

To list the secrets within a target key vault run the following command:

az keyvault secret list [--vault-name / --id]

To list the certificates within a target key vault run the following command:

az keyvault certificate list [--vault-name / --id]

To list the keys within a target key vault run the following command:

az keyvault secret list [--vault-name / --id]

--id represents the full URI of the vault. --vault-name represents the name and must be present if --id is missing.

Using Azure PowerShell

To list key vaults within a subscription run the following command:

Get-AzKeyVault

To list all secrets in a key vault run the following command:

Get-AzKeyVaultSecret -VaultName '<vaultName>'

Expected Result

Azure Key Vaults should be created and secrets should be stored within them rather than in application code or configuration files.

Remediation

Remediation has 2 steps:

1. Set up the Key Vault
2. Set up the App Service to use the Key Vault

Step 1: Set up the Key Vault

Using Azure CLI

az keyvault create --name "<name>" --resource-group "<myResourceGroup>" --location myLocation

Using Azure PowerShell

New-AzKeyvault -name <name> -ResourceGroupName <myResourceGroup> -Location <myLocation>

Step 2: Set up the App Service to use the Key Vault

Configure the App Service to reference secrets from Key Vault using Key Vault references in application settings. Use a system-assigned managed identity with appropriate access policies granting "get" permission on secrets.

Default Value

By default, no Azure Key Vaults are created.

References

1. https://docs.microsoft.com/en-us/azure/app-service/app-service-key-vault-references
2. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-identity-management#im-3-manage-application-identities-securely-and-automatically
3. https://docs.microsoft.com/en-us/cli/azure/keyvault?view=azure-cli-latest
4. https://docs.microsoft.com/en-us/cli/azure/keyvault?view=azure-cli-latest

Profile

Level 2 | Manual