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Azure Key Vault Security

   November 2, 2024

Azure Key Vault is a cloud service provided by Microsoft Azure designed to securely store and manage sensitive information such as cryptographic keys, secrets (like API keys or passwords), and digital certificates. Azure Key Vault helps centralize application secrets, reducing the risk of accidental exposure while also providing easy management, access control, and monitoring.

Here’s a beginner-friendly overview of the different security methods, functions, and features in Azure Key Vault, covering how to create, configure, manage, and monitor keys, secrets, and certificates.

1. Overview of Azure Key Vault

Azure Key Vault enables secure storage and access to sensitive data. It’s useful for both individual applications and large organizations, providing:

  • Centralized Storage: A secure, centralized location for sensitive data.
  • Access Control: Integration with Azure Active Directory (Azure AD) for controlling access to the vault.
  • Audit Logging: Tracks access to the vault for security monitoring and compliance.

Core Components

  • Keys: Used for encryption, decryption, signing, and verification.
  • Secrets: Holds sensitive information like passwords, API keys, or connection strings.
  • Certificates: Stores and manages SSL/TLS certificates used for secure communication.

2. Setting Up and Configuring Azure Key Vault

Step 1: Create an Azure Key Vault

  1. Go to Azure Portal:
  • Log in to Azure Portal.
  • Navigate to All Services > Key Vaults > Create.
  1. Configure Key Vault Settings:
  • Name: Give the Key Vault a unique name.
  • Subscription: Select your Azure subscription.
  • Resource Group: Choose an existing resource group or create a new one.
  • Location: Select the geographic region for the vault.
  • Pricing Tier: Choose between Standard and Premium (Premium supports hardware-backed keys).
  1. Access Policies:
  • Define who has access to the Key Vault. You can grant specific permissions (e.g., for managing keys, secrets, or certificates) to users or service principals.
  • For simplicity, start with default access settings and modify them as needed.
  1. Review and Create:
  • After configuring the settings, click Review + Create and then Create to provision the Key Vault.

3. Managing Keys in Azure Key Vault

Keys Overview

Keys are cryptographic keys used for data encryption, decryption, signing, and verifying digital signatures. They help secure application data and communications.

Creating a Key

  1. Go to Key Vault:
  • Open the created Key Vault in the Azure portal.
  • Navigate to Keys and click + Generate/Import.
  1. Key Settings:
  • Options: Choose to generate a new key or import an existing one.
  • Name: Assign a name to the key (e.g., myEncryptionKey).
  • Key Type: Select RSA (suitable for most encryption) or EC (Elliptic Curve).
  • Key Size: Specify the size (2048 or 4096 bits for RSA keys).
  • Activation and Expiry: Set an optional activation and expiration date for security.
  1. Create Key:
  • After configuring, click Create to add the key to Key Vault.

Example Usage: Encrypting Data with a Key

With Azure SDK or REST API, you can encrypt data using a key from Key Vault. Here’s an example in Python:

from azure.identity import DefaultAzureCredential
from azure.keyvault.keys import KeyClient
from azure.keyvault.keys.crypto import CryptographyClient, EncryptionAlgorithm

# Set up the Key Vault and Key
vault_url = "https://<your-key-vault-name>.vault.azure.net"
credential = DefaultAzureCredential()
key_client = KeyClient(vault_url=vault_url, credential=credential)
key = key_client.get_key("myEncryptionKey")

# Initialize Cryptography Client
crypto_client = CryptographyClient(key, credential=credential)

# Encrypt data
plaintext = b"Hello, world!"
encrypt_result = crypto_client.encrypt(EncryptionAlgorithm.rsa_oaep, plaintext)
print("Encrypted data:", encrypt_result.ciphertext)

Managing and Rotating Keys

Regularly rotating keys helps maintain security:

  • Rotate Manually: Re-generate keys using Key Vault when required.
  • Automatic Rotation (Premium only): Set policies to automatically rotate keys based on time intervals.

Monitoring Keys

  1. Azure Monitor and Alerts:
  • Enable Azure Monitor to track access to keys, failed attempts, and usage.
  • Set up alerts for key usage to identify unusual activity.

4. Managing Secrets in Azure Key Vault

Secrets Overview

Secrets in Key Vault store sensitive information like API keys, database connection strings, and passwords.

Creating a Secret

  1. Go to Key Vault:
  • Navigate to the Secrets section and click + Generate/Import.
  1. Secret Settings:
  • Name: Enter a name for the secret (e.g., dbConnectionString).
  • Value: Input the secret value (e.g., the actual connection string or API key).
  • Activation and Expiry: Set optional activation and expiration dates to control the lifecycle.
  1. Create Secret:
  • Click Create to add the secret to Key Vault.

Example Usage: Retrieving a Secret

Applications can access secrets in Key Vault using Azure SDK or REST API. Here’s an example in Python:

from azure.identity import DefaultAzureCredential
from azure.keyvault.secrets import SecretClient

# Set up the Key Vault
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("Database connection string:", retrieved_secret.value)

Rotating and Updating Secrets

Updating secrets helps to keep sensitive information secure:

  • Manual Update: Replace the secret value by updating the secret.
  • Versioning: Each update creates a new version, allowing applications to retrieve a previous version if needed.

Monitoring Secrets

  1. Access Logs:
  • Track access to secrets using Azure Monitor to detect unauthorized attempts.
  1. Expiration Alerts:
  • Set up alerts to notify administrators before a secret expires.

5. Managing Certificates in Azure Key Vault

Certificates Overview

Certificates in Key Vault are primarily used for SSL/TLS encryption to secure communications. Azure Key Vault helps with certificate lifecycle management, including renewal and auto-renewal.

Creating a Certificate

  1. Go to Key Vault:
  • Navigate to the Certificates section and click + Generate/Import.
  1. Certificate Settings:
  • Method: Choose to generate a new certificate or import an existing one.
  • Certificate Name: Give a name (e.g., mySSLCertificate).
  • Policy: Configure the certificate policy to define the type (e.g., SSL, Client Auth), validity period, and renewals.
  1. Create Certificate:
  • After configuration, click Create to add the certificate to Key Vault.

Example Usage: Retrieving and Using a Certificate

Certificates are often retrieved and installed on application servers. Here’s a Python example to get a certificate:

from azure.identity import DefaultAzureCredential
from azure.keyvault.certificates import CertificateClient

# Set up the Key Vault
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:", certificate)

Managing and Renewing Certificates

  • Manual Renewal: Renew certificates manually within Key Vault.
  • Auto-Renewal: Configure Key Vault to renew certificates automatically, useful for SSL certificates that require frequent renewal.

Monitoring Certificates

  1. Certificate Expiry Alerts:
  • Set up expiration alerts in Azure Monitor to be notified before certificates expire.
  1. Usage Logs:
  • Use Azure Monitor to log and audit certificate access, ensuring security compliance.

6. Access Control and Security Management

Azure Key Vault integrates with Azure Active Directory (Azure AD) to control access to keys, secrets, and certificates.

  1. Access Policies:
  • In Key Vault > Access policies, add policies for each user or application that needs access.
  • Grant only necessary permissions (e.g., Get for reading secrets, List for viewing keys).
  1. Role-Based Access Control (RBAC):
  • Define roles and assign them to specific users or groups to follow the principle of least privilege.

Monitoring Access with Logs and Alerts

  1. Azure Monitor:
  • Track and set up alerts for unusual access or failed attempts to access the vault.
  1. Activity Logs:
  • Use Activity Logs in the Azure portal to audit who accessed, modified, or attempted to access Key Vault items.

7. Example Use Case: Securely Storing and Accessing Database Credentials

  1. Store Database Connection String as a Secret:
  • Store the connection string for a database as a secret in Key Vault (dbConnectionString).
  1. Retrieve the Secret in an Application:
  • The application uses the Azure SDK to retrieve the dbConnectionString at runtime.
  1. Monitor Access to the Secret:
  • Set up Azure Monitor to track and alert on access attempts, ensuring only authorized applications retrieve the connection string.

Azure Key Vault provides a comprehensive suite of features to help you secure and manage sensitive information in the cloud. By creating and using keys, secrets, and certificates, you can ensure your application data and communications are secure while maintaining control over access and lifecycle management.

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Author: tonyhughes