A company requires a secure and reliable way to manage secrets and encryption keys. What Google Cloud service should they use, and what practices should be followed to ensure key security and lifecycle management?
For securely managing secrets and encryption keys, a company should use Google Cloud Key Management Service (KMS) along with Secret Manager. Cloud KMS is primarily for managing encryption keys, while Secret Manager is best for managing application secrets such as passwords, API keys, and other sensitive data. Using these two services together will provide a comprehensive, secure, and reliable solution.
1. Google Cloud Key Management Service (KMS):
Purpose: Cloud KMS is a managed service for creating, using, rotating, and destroying encryption keys. It is designed for protecting encryption keys used to encrypt and decrypt data at rest or in transit.
Key Management: KMS provides centralized key management, which allows for managing keys from a single interface. Keys can be created within KMS, imported from external systems, or generated using a Cloud Hardware Security Module (HSM).
Key Hierarchy: Keys are organized in a hierarchy with keyrings and crypto keys which allows for granular access controls for managing different sets of encryption keys. Keyrings are used for grouping crypto keys, and this allows for better management of keys.
Key Rotation: KMS supports automatic and manual key rotation, which is essential to limit the impact of a potential key compromise. Keys should be rotated periodically to limit exposure if compromised.
Auditing: KMS integrates with Cloud Logging, providing audit logs for all key access and management operations. Audit logging provides a log of all key usage, which can be used to identify potential issues.
Compliance: KMS helps organizations comply with various compliance requirements, such as PCI DSS, HIPAA, and GDPR. The use of KMS facilitates compliance with most regulatory standards.
Example:
A company uses Cloud KMS to manage keys for encrypting data stored in Cloud Storage, Cloud SQL, and BigQuery. They have multiple keyrings to separate keys used by different applications and each key is rotated every 90 days.
2. Google Cloud Secret Manager:
Purpose: Secret Manager provides a secure and centralized way to store, manage, and access application secrets. It prevents hardcoding secrets in configuration files or code. Secret Manager helps eliminate secrets sprawl, as all secrets can be managed from one place.
Secret Versioning: Secret Manager supports secret versioning, which means you can track changes to the secrets over time and roll back if there are issues. Version history also provides an audit trail.
Secret Replication: Secrets are automatically replicated across multiple regions, providing high availability. If secrets are replicated in regions that are closer to application instances, it will also ensure lower latency access.
Access Control: It integrates with IAM, providing granular access control over secrets. Use IAM to grant specific principals (users, service accounts) access to specific secrets.
Auditing: Secret Manager logs all secret access, configuration, and management operations using Cloud Logging. All access, modifications and configuration changes are auditable.
Integration: Secret Manager integrates with various other Google Cloud services, making it easy to use the stored secrets in applications, and other services.
Example:
A web application uses Secret Manager to store database credentials, API keys, and other sensitive information. Access is granted to a service account used by the web application. Secret values are rotated every 30 days, and version history is tracked for compliance.
3. Practices for Secure Key and Secret Management:
Principle of Least Privilege: Grant users and service accounts only the necessary permissions for keys and secrets. Ensure only the required teams and service accounts have access to a key or a secret. Avoid giving broad access to all secrets and keys.
Key Rotation: Implement regular automatic key rotation for encryption keys and secrets using KMS and Secret Manager. Keys should be rotated regularly to minimize the impact of any key compromise.
Secret Rotation: Periodically rotate application secrets to limit exposure. Use Secret Manager’s secret versioning feature to manage the rotation.
Infrastructure as Code (IaC): Use IaC tools like Terraform or Deployment Manager to manage keys and secrets as code. This makes it easy to manage the secrets and keys in a version controlled manner.
Avoid Hardcoding Secrets: Never hardcode any secrets directly in your code, configuration files, or environment variables. Use Secret Manager to retrieve secrets programmatically.
Secure Storage: Store the state file used by IAC tools in a secure location, and use encryption on these files to protect them from unauthorized access.
Auditing and Monitoring: Monitor all key and secret access using Cloud Logging and set up alerts for any suspicious activities.
Key and Secret Naming: Implement a clear, well documented and standardized naming convention for keys and secrets, using best practices for all resources.
Regular Reviews: Regularly review key and secret access policies and usage patterns to identify any vulnerabilities or misconfigurations.
Backup and Recovery: Establish a backup and recovery strategy for KMS keys, especially for external keys imported into Cloud KMS. In the case of imported keys, there has to be a backup of these external keys, in a secure location.
Separation of Duties: Separate the duties for managing keys and secrets, from duties associated with managing access to the resources.
Use Workload Identity: When deploying applications on GKE use workload identity to use service accounts, rather than storing and using the service account keys in code or config files.
Use Cloud HSM: For a higher level of security, use Cloud HSM instead of software keys for Cloud KMS to provide Hardware security module protection of encryption keys. This adds another layer of security over the software based keys.
4. Implementation Steps:
Create Keyrings and Crypto Keys:
Create keyrings in Cloud KMS to group your crypto keys based on application or business unit.
Create new crypto keys in Cloud KMS, using a location and key size based on your requirements.
Store Secrets:
Create secrets in Secret Manager and add secret versions with the actual secret values.
Grant Permissions:
Use IAM to grant access to KMS keys and Secret Manager secrets to service accounts, and other users based on the application requirements.
Retrieve Secrets:
Use the Secret Manager client libraries or API to retrieve secrets programmatically within applications.
Use KMS for Encryption:
Encrypt data using Cloud KMS crypto keys, to enable secure storage of the data in cloud storage, database and other services.
Implement Rotation:
Set up automatic key rotation in KMS, and schedule key and secret rotations on Secret Manager.
Example Scenario:
A web application uses a Cloud KMS key to encrypt data, and it stores its database credentials in Secret Manager. The web application has been configured using workload identity, which uses a service account that only has access to the required key, and secret. The keys are automatically rotated every 90 days and the secrets are rotated every 30 days. Any usage or modification of the keys and secrets is audited using Cloud Logging.
In summary, managing secrets and encryption keys effectively requires using both Cloud KMS for keys, and Secret Manager for secrets, along with a set of best practices to ensure security. By implementing strong policies and automating key and secret rotation, organizations can significantly improve their overall security posture.