Security for Azure Container Registry

This article provides guidance on securing your Azure Container Registry (ACR) instances to protect your container images and sensitive data.

Introduction to ACR Security

Azure Container Registry is a managed, private Docker registry service that you use to build, store, and manage container images and related artifacts. Securing your registry is critical for maintaining the integrity and confidentiality of your applications. ACR offers several layers of security, including network controls, authentication, authorization, and image scanning.

Key Security Features

1. Authentication and Authorization

ACR supports multiple authentication methods and integrates with Azure Active Directory (Azure AD) for robust authorization.

  • Service Principals: Ideal for programmatic access, such as CI/CD pipelines.
  • Managed Identities: Enables Azure resources (like AKS or Azure Functions) to authenticate to ACR without managing credentials.
  • User Credentials: For direct access by individual users.
  • Role-Based Access Control (RBAC): Assign granular permissions (e.g., Reader, Contributor, Admin) to users and service principals.

2. Network Security

Control network access to your ACR instance to prevent unauthorized access.

  • Private Endpoints: Integrate ACR into your virtual network, allowing access via a private IP address.
  • Service Endpoints: Restrict access to ACR from specific virtual networks and subnets.
  • Firewall Rules: Define IP address ranges that are allowed to access the registry.

3. Image Vulnerability Scanning

ACR integrates with Microsoft Defender for Cloud to scan images for known vulnerabilities.

When enabled, Defender for Cloud scans newly pushed images and existing images for vulnerabilities in packages and libraries. Alerts are generated, allowing you to remediate identified security issues.

4. Data Encryption

All data stored in Azure Container Registry is encrypted at rest and in transit.

  • At Rest: Images and other artifacts are encrypted using AES-256.
  • In Transit: All communication with ACR uses TLS/SSL encryption.

Best Practices for ACR Security

  • Least Privilege: Grant only the necessary permissions to users and service principals.
  • Regular Scanning: Ensure vulnerability scanning is enabled and actively monitored.
  • Network Isolation: Utilize private endpoints or service endpoints for enhanced network security.
  • Auditing: Review ACR logs to monitor access and activity.
  • Credential Management: Avoid hardcoding credentials; use managed identities or Azure Key Vault.
Important: Regularly review and update your security configurations to adapt to evolving threats and Azure best practices.

Example: Authenticating with a Service Principal

Here's a basic example of how to authenticate to ACR using a service principal:


az acr login --name myregistry --username  --password

For more advanced scenarios and detailed configuration, refer to the official Azure documentation.