Getting Started with Azure Key Vault

What is Azure Key Vault?

Azure Key Vault is a cloud service for securely storing and accessing secrets, encryption keys, and certificates. It helps solve the following problems:

• Secrets Management: Securely store tokens, passwords, API keys, and other secrets
• Key Management: Create and control encryption keys for your data
• Certificate Management: Provision, manage, and deploy SSL/TLS certificates
• Hardware Security Module (HSM) Support: Protect keys with FIPS 140-2 Level 2 validated HSMs

How to Use It

Creating a Key Vault

Using Azure CLI

# Create resource group
az group create --name rg-keyvault --location eastus

# Create Key Vault with soft delete and purge protection
az keyvault create \
  --name kv-myapp-prod \
  --resource-group rg-keyvault \
  --location eastus \
  --enable-soft-delete true \
  --enable-purge-protection true \
  --retention-days 90

Using Azure Portal

1. Navigate to Key Vault in Azure Portal
2. Click + Create
3. Select subscription and resource group
4. Enter unique vault name (3-24 characters, alphanumeric and hyphens)
5. Choose region and pricing tier (Standard or Premium with HSM)
6. Configure Access Configuration (Azure RBAC recommended over legacy access policies)
7. Enable Soft delete (90-day retention recommended)
8. Enable Purge protection for production vaults
9. Review and create

Storing and Retrieving Secrets

# Store a secret
az keyvault secret set \
  --vault-name kv-myapp-prod \
  --name db-connection-string \
  --value "Server=myserver;Database=mydb;User=admin;Password=P@ssw0rd"

# Retrieve a secret
az keyvault secret show \
  --vault-name kv-myapp-prod \
  --name db-connection-string \
  --query value -o tsv

# List all secrets
az keyvault secret list --vault-name kv-myapp-prod -o table

Managing Encryption Keys

# Create an encryption key
az keyvault key create \
  --vault-name kv-myapp-prod \
  --name my-encryption-key \
  --protection software \
  --kty RSA \
  --size 2048

# For HSM-protected keys (Premium tier only)
az keyvault key create \
  --vault-name kv-myapp-prod \
  --name my-hsm-key \
  --protection hsm \
  --kty RSA-HSM \
  --size 4096

Terraform Example

# Create Key Vault
resource "azurerm_key_vault" "main" {
  name                        = "kv-${var.project}-${var.environment}"
  location                    = azurerm_resource_group.main.location
  resource_group_name         = azurerm_resource_group.main.name
  tenant_id                   = data.azurerm_client_config.current.tenant_id
  sku_name                    = "premium"
  
  # Security features
  soft_delete_retention_days  = 90
  purge_protection_enabled    = true
  
  # Network security
  network_acls {
    default_action             = "Deny"
    bypass                     = "AzureServices"
    ip_rules                   = ["203.0.113.0/24"]
    virtual_network_subnet_ids = [azurerm_subnet.private.id]
  }
  
  # Enable Azure RBAC for data plane
  enable_rbac_authorization   = true
}

# Store a secret
resource "azurerm_key_vault_secret" "db_password" {
  name         = "database-password"
  value        = random_password.db_password.result
  key_vault_id = azurerm_key_vault.main.id
}

# Grant access using RBAC (recommended)
resource "azurerm_role_assignment" "secrets_user" {
  scope                = azurerm_key_vault.main.id
  role_definition_name = "Key Vault Secrets User"
  principal_id         = azurerm_user_assigned_identity.app.principal_id
}

CI/CD Integration

GitHub Actions

name: Deploy with Key Vault Secrets

on: [push]

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      
      - name: Azure Login
        uses: azure/login@v1
        with:
          creds: ${{ secrets.AZURE_CREDENTIALS }}
      
      - name: Get secrets from Key Vault
        uses: azure/get-keyvault-secrets@v1
        with:
          keyvault: "kv-myapp-prod"
          secrets: 'db-connection-string, api-key, storage-account-key'
        id: keyvault
      
      - name: Use secrets in deployment
        run: |
          echo "Deploying with connection string"
          # Secrets available as: ${{ steps.keyvault.outputs.db-connection-string }}

Azure DevOps

variables:
- group: KeyVaultSecrets  # Variable group linked to Key Vault

steps:
- task: AzureKeyVault@2
  inputs:
    azureSubscription: 'Production'
    KeyVaultName: 'kv-myapp-prod'
    SecretsFilter: '*'
    RunAsPreJob: true

Best Practices

Use Managed Identities for Access

❌ Avoid: Storing Key Vault credentials in application code or environment variables ✅ Use: Assign Managed Identity to your application and grant Key Vault permissions

# Assign system-assigned managed identity to VM
az vm identity assign \
  --resource-group rg-app \
  --name vm-app-01

# Grant Key Vault Secrets User role
az role assignment create \
  --role "Key Vault Secrets User" \
  --assignee <managed-identity-principal-id> \
  --scope /subscriptions/{sub-id}/resourceGroups/rg-keyvault/providers/Microsoft.KeyVault/vaults/kv-myapp-prod

Enable Soft Delete and Purge Protection

• Soft Delete: Retains deleted vaults and secrets for 7-90 days (90 recommended)
• Purge Protection: Prevents permanent deletion during retention period
• Critical for Production: Always enable both for production environments

Use Azure RBAC Over Access Policies

• Modern Approach: Azure RBAC provides centralized access management
• Granular Control: Built-in roles like Key Vault Secrets User, Key Vault Crypto Officer
• Consistency: Same access control model as other Azure resources

Implement Network Security

# Restrict access to specific networks
az keyvault network-rule add \
  --name kv-myapp-prod \
  --resource-group rg-keyvault \
  --vnet-name vnet-prod \
  --subnet subnet-app

# Set default action to deny
az keyvault update \
  --name kv-myapp-prod \
  --resource-group rg-keyvault \
  --default-action Deny

Use Private Endpoints

For production workloads, disable public access and use Private Link:

• Secrets never traverse public internet
• Integrated with VNet DNS resolution
• Compliant with zero-trust security model

Secret Rotation Strategy

• Automate Rotation: Use Key Vault's integrated rotation for supported services
• Versioning: Key Vault maintains secret versions automatically
• Monitoring: Set up alerts for expiring secrets and certificates

Things to Avoid

❌ Don't hardcode secrets in application code, even temporarily ❌ Don't use access policies for new deployments (use RBAC) ❌ Don't grant overly permissive access (e.g., Key Vault Administrator for apps) ❌ Don't disable soft delete and purge protection in production ❌ Don't allow unrestricted network access in production vaults ❌ Don't store non-sensitive configuration data in Key Vault (use App Configuration) ❌ Don't share secrets across multiple environments (dev/prod) ❌ Don't neglect to monitor access logs and failed authentication attempts

✅ Do use separate Key Vaults for different environments ✅ Do implement least privilege access with RBAC ✅ Do enable diagnostic logging to Log Analytics ✅ Do use managed identities for service-to-service authentication ✅ Do regularly review and audit access permissions ✅ Do implement secret expiration dates and rotation ✅ Do use Premium tier with HSM for highly sensitive keys

Monitoring and Logging

Enable Diagnostic Settings

# Send logs to Log Analytics
az monitor diagnostic-settings create \
  --name KeyVaultLogs \
  --resource /subscriptions/{sub-id}/resourceGroups/rg-keyvault/providers/Microsoft.KeyVault/vaults/kv-myapp-prod \
  --logs '[{"category": "AuditEvent", "enabled": true}]' \
  --metrics '[{"category": "AllMetrics", "enabled": true}]' \
  --workspace /subscriptions/{sub-id}/resourceGroups/rg-monitoring/providers/Microsoft.OperationalInsights/workspaces/law-prod

Key Metrics to Monitor

• Vault Availability: Target 99.9%+
• Total API Hits: Monitor for unusual spikes
• Failed Requests: Investigate authentication failures
• Latency: Service API latency (P95, P99)

Set Up Alerts

# Alert on failed authentication attempts
az monitor metrics alert create \
  --name FailedKeyVaultAuth \
  --resource-group rg-keyvault \
  --scopes /subscriptions/{sub-id}/resourceGroups/rg-keyvault/providers/Microsoft.KeyVault/vaults/kv-myapp-prod \
  --condition "count ServiceApiResult == 401 > 10" \
  --window-size 5m \
  --evaluation-frequency 1m

Common Use Cases

1. Application Secrets: Database connection strings, API keys
2. Encryption Keys: For Azure Storage, Disk Encryption, Always Encrypted
3. SSL/TLS Certificates: Automated provisioning and renewal
4. DevOps Pipelines: Secure credential storage for CI/CD
5. Bring Your Own Key (BYOK): Import your own encryption keys
6. Signing Operations: Code signing, document signing

Related Resources

• Key Vault Overview
• Secrets Management
• Managed Identities
• Private Link Configuration