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Azure Key Vault Authentication and Authorization

   November 2, 2024

Azure Key Vault is a Microsoft cloud service designed to help you store and manage sensitive information like cryptographic keys, secrets (e.g., passwords, API keys), and certificates securely. It provides strong authentication and authorization features, allowing you to control access to your data, monitor its usage, and manage its lifecycle easily.

Here’s a beginner-friendly guide to understanding the different authentication and authorization methods for Azure Key Vault, covering setup, usage, management, and monitoring for keys, secrets, and certificates.

1. Overview of Azure Key Vault Authentication and Authorization

Key Terms:

  • Authentication: Verifying the identity of a user or application trying to access Key Vault.
  • Authorization: Granting specific permissions to authenticated users or applications to control what actions they can perform on Key Vault resources (e.g., reading a secret, creating a key).

Main Authentication and Authorization Methods

Azure Key Vault integrates with Azure Active Directory (Azure AD) to provide secure authentication and authorization:

  1. Azure AD Authentication: Applications, users, or services authenticate through Azure AD to gain access to Key Vault.
  2. Role-Based Access Control (RBAC): Azure’s system for controlling access using roles, allowing you to assign permissions to specific users or applications.
  3. Access Policies: Key Vault-specific permissions to define what operations a user or application can perform on secrets, keys, or certificates.

Key Vault Resources:

  • Keys: For cryptographic operations, including encryption, decryption, signing, and verifying.
  • Secrets: For storing sensitive data such as passwords and API keys.
  • Certificates: For managing SSL/TLS certificates used for secure communications.

2. Setting Up Azure Key Vault and Authentication

Step 1: Create an Azure Key Vault

  1. Log into Azure Portal:
  1. Create a New Key Vault:
  • Select Create Key Vault and fill in the following details:
    • Subscription: Select your Azure subscription.
    • Resource Group: Choose an existing resource group or create a new one.
    • Vault Name: Enter a unique name for your Key Vault.
    • Region: Choose a geographic location for the vault.
    • Pricing Tier: Choose Standard or Premium (Premium offers additional features like hardware security modules).
  1. Review and Create:
  • Review your settings and click Create to set up the Key Vault.

Step 2: Enable Authentication Using Azure AD

To access Key Vault, applications and users must authenticate through Azure AD. For applications, you register the app with Azure AD and assign it permissions to the Key Vault.

  1. Register the Application in Azure AD:
  • In the Azure portal, go to Azure Active Directory > App registrations > New registration.
  • Enter the app’s Name, specify the supported account types, and configure redirect URIs if needed.
  • Note the Application (client) ID and Directory (tenant) ID as you’ll need them later.
  1. Generate a Client Secret:
  • In Certificates & secrets under the registered application, create a new client secret, which acts as the application’s password.
  1. Assign Access to Key Vault:
  • Go to your Key Vault, select Access policies, and create a policy for the application.
  • Assign Permissions based on what the app should access (e.g., read or write permissions for secrets or keys).

3. Authorization Methods in Azure Key Vault

Azure Key Vault supports Access Policies and RBAC for authorization.

Using Access Policies

Access policies define specific actions users or applications can perform on vault resources:

  1. Navigate to Key Vault:
  • In the Azure portal, open your Key Vault and go to Access policies.
  1. Configure Access Policy:
  • Click on + Add Access Policy and select permissions for Keys, Secrets, or Certificates (e.g., Get, List, Create, Delete).
  • Choose a principal (user or application) by searching for the person or registered app.
  • Save the access policy.

Using Role-Based Access Control (RBAC)

Azure RBAC is more flexible, offering broader management capabilities.

  1. Assign Roles in Azure Key Vault:
  • In Azure Key Vault > Access control (IAM), click + Add role assignment.
  • Select a role (e.g., Key Vault Contributor, Key Vault Reader).
  • Assign the role to a user, group, or application.
  • RBAC roles allow you to control access at the subscription, resource group, or Key Vault level.

4. Managing and Using Keys in Azure Key Vault

Creating and Managing Keys

  1. Create a New Key:
  • In Key Vault > Keys, select + Generate/Import.
  • Configure the key:
    • Name: Give the key a name (e.g., encryptionKey).
    • Key Type: RSA or EC (Elliptic Curve).
    • Key Size: Choose key size (e.g., 2048 or 4096 bits for RSA).
    • Expiration: Set an optional expiration date.
  1. Using the Key for Encryption (Python SDK Example):
from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient
from azure.keyvault.keys.crypto import CryptographyClient, EncryptionAlgorithm

vault_url = "https://<your-key-vault-name>.vault.azure.net"
credential = DefaultAzureCredential()

# Get the key
key_client = KeyClient(vault_url=vault_url, credential=credential)
key = key_client.get_key("encryptionKey")

# Use the key for encryption
crypto_client = CryptographyClient(key, credential=credential)
plaintext = b"Confidential message"
encrypt_result = crypto_client.encrypt(EncryptionAlgorithm.rsa_oaep, plaintext)
print("Encrypted data:", encrypt_result.ciphertext)

Rotating and Monitoring Keys

  1. Manual Key Rotation:
  • Re-generate or update keys to maintain security.
  1. Monitoring Key Usage:
  • Enable Azure Monitor to track access to keys and set up alerts.

5. Managing and Using Secrets in Azure Key Vault

Creating and Managing Secrets

  1. Create a Secret:
  • In Key Vault > Secrets, click + Generate/Import.
  • Enter the name and value of the secret (e.g., API key or database password).
  • Activate and Expiration Dates: Set optional activation and expiration dates.
  1. Retrieving a Secret (Python SDK Example):
from azure.identity import DefaultAzureCredential
from azure.keyvault.secrets import SecretClient

vault_url = "https://<your-key-vault-name>.vault.azure.net"
credential = DefaultAzureCredential()
secret_client = SecretClient(vault_url=vault_url, credential=credential)

# Retrieve the secret
secret_name = "dbConnectionString"
retrieved_secret = secret_client.get_secret(secret_name)
print("Secret value:", retrieved_secret.value)

Updating and Monitoring Secrets

  1. Versioning:
  • Every update creates a new version of the secret, allowing rollback if needed.
  1. Monitoring Access:
  • Set up Azure Monitor alerts to notify you if someone accesses or attempts to access secrets.

6. Managing and Using Certificates in Azure Key Vault

Creating and Managing Certificates

  1. Create a Certificate:
  • In Key Vault > Certificates, click + Generate/Import.
  • Options: Choose between generating a new certificate or importing an existing one.
  • Policy: Define certificate type (SSL/TLS), validity period, and renewal settings.
  1. Retrieving a Certificate (Python SDK Example):
from azure.identity import DefaultAzureCredential
from azure.keyvault.certificates import CertificateClient

vault_url = "https://<your-key-vault-name>.vault.azure.net"
credential = DefaultAzureCredential()
cert_client = CertificateClient(vault_url=vault_url, credential=credential)

# Retrieve the certificate
cert_name = "mySSLCertificate"
certificate = cert_client.get_certificate(cert_name)
print("Certificate details:", certificate)

Managing and Monitoring Certificates

  1. Renewal:
  • Manually renew certificates or enable auto-renewal if supported.
  1. Expiration Alerts:
  • Configure alerts in Azure Monitor to notify administrators before certificates expire.

7. Monitoring and Auditing Access in Azure Key Vault

Setting Up Logs and Alerts

  1. Enable Diagnostics:
  • In Key Vault > Diagnostics settings, enable diagnostics and send logs to Azure Monitor, Log Analytics, or Event Hubs.
  1. Create Alerts:
  • Set up Azure Monitor alerts to notify administrators of access attempts, expirations, or specific actions on keys, secrets, or certificates.

Example Monitoring Use Case

Suppose you have an application that retrieves a database password stored as a secret in Key Vault. You can set up Azure Monitor to alert you if the password is accessed frequently, indicating potential misuse or application issues.

Azure Key Vault is a powerful tool for securing application secrets, keys, and certificates with Azure AD integration for strong access control. By following these steps, you can securely store, manage,

and monitor sensitive information, ensuring data protection and compliance.

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Author: tonyhughes