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Best practices for protecting secrets

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This article provides guidance on protecting your secrets and reducing the risk of unauthorized access. Follow this guidance to help ensure you do not store sensitive information such as credentials in code, GitHub repositories, logs, continuous integration/continuous deployment (CI/CD) pipelines, and so forth. The guidance in this article is compiled from recommendations of individual services, as well as from the Microsoft Cloud Security Benchmark (MCSB).

General best practices

In today's digital landscape, securing sensitive information such as application credentials and secrets is paramount. A breach can lead to severe consequences, including data loss, financial penalties, and damage to reputation. Implementing a comprehensive secret management strategy is essential to mitigating these risks.

Conduct an audit to identify secrets

Before you can secure your secrets, you need to know where they are. Conducting a thorough audit of your systems and applications helps identify all the sensitive information that needs protection. This includes passwords, API keys, connection strings, and other credentials. Regular audits ensure that new secrets are accounted for and existing ones are properly managed.

It's important to note that even dynamically created secrets, such as OAuth tokens, which may be temporary, still need to be safeguarded with the same rigor as long-term secrets.

Avoid hardcoding secrets

Embedding secrets directly into your code or configuration files is a significant security risk. If your codebase is compromised, so are your secrets. Instead, use environment variables or configuration management tools that keep secrets out of your source code. This practice minimizes the risk of accidental exposure and simplifies the process of updating secrets.

Additionally, integrating secret retrieval into your automated deployment pipeline and using secret injection patterns can prevent secrets from being accidentally exposed in logs or version control, further enhancing the security of your deployment process.

See Recommendations for protecting application secrets

Use secure key stores

Leveraging secure key stores ensures that your secrets are stored in a secure, encrypted location. Services like Azure Key Vault and Azure Managed HSM provide robust security features, including access control, logging, and automatic rotation. This approach centralizes the management of your secrets and reduces the risk of unauthorized access.

For even greater security, particularly for highly sensitive or critical secrets, consider encrypting the secret with a key stores in a Hardware Security Model (HSM), which offer enhanced protection compared to software-based secret stores. For an overview of all the key management offering in Azure and guidance on which to choose, see Key management in Azure and How to choose the right key management solution.

Implement secret scanning tools

Regularly scanning your codebase for embedded secrets can prevent accidental exposure. Tools like Azure DevOps Credential Scanner and GitHub secret scanning feature can automatically detect and alert you to any secrets found in your repositories. Integrating these tools into your CI/CD pipeline ensures continuous monitoring. It is crucial to treat any secret found by these scanning tools as compromised, which means it should be immediately revoked and replaced to maintain the integrity of your security posture.

Leverage managed identities

Managed identities in Azure provide a secure way for applications to authenticate to Azure services without storing credentials in the code. By enabling managed identities for Azure resources, you can securely access Azure Key Vault and other services, reducing the need to handle secrets manually. This approach not only minimizes the creation of secrets but also reduces the surface area for potential breaches, as the responsibility for managing credentials is delegated to the platform.

Apply granular access control

Follow the principle of least privilege by applying granular access control to your secrets. Use Azure role-based access control (RBAC) to ensure that only authorized entities have access to specific secrets. Regularly review and update access permissions to prevent unauthorized access. It's also advisable to implement distinct roles such as user, administrator, and auditor to manage access to secrets, ensuring that only trusted identities have the appropriate level of permission.

See the Azure Key Vault RBAC guide.

Rotate secrets regularly

Secrets are susceptible to leakage or exposure over time. Regularly rotating your secrets reduces the risk of unauthorized access. You can rotate secrets in Azure Key Vault for certain secrets; for those that cannot be automatically rotated, establish a manual rotation process and ensure they are purged when no longer in use.

Automating the secret rotation process and building redundancy into your secret management can ensure that rotation does not disrupt service availability. Implementing retry logic and concurrent access patterns in your code can help minimize issues during the rotation window.

Monitor and log access

Enable logging and monitoring for your secret management system to track access and usage. Use Key Vault logging and/or services like Azure Monitor and Azure Event Grid, to monitor all activities related to your secrets. This provides visibility into who accessed your secrets and helps detect any suspicious behavior or potential security incidents. Maintaining detailed audit trails is critical for inspecting and validating access to secrets, which can help prevent identity theft, avoid repudiation, and reduce unnecessary exposure.

Implement network isolation

Reduce the exposure of your secrets by implementing network isolation. Configure firewalls and network security groups to restrict access to your key vaults. Only allow trusted applications and services to access your secrets, minimizing the attack surface and preventing unauthorized access. Additionally, consider using multiple key vaults to create isolation boundaries for different components, ensuring that if one component is compromised, it cannot gain control of other secrets or the entire workload.

Encrypt secrets at rest and in transit

Ensure that your secrets are encrypted both at rest and in transit. Azure Key Vault securely stores secrets using envelope encryption, where Data Encryption Keys (DEKs) are encrypted by Key Encryption Keys (KEKs), providing an additional layer of security. This approach enhances protection against unauthorized access. Additionally, use secure communication protocols like HTTPS to encrypt data in transit between your applications and the key vault, ensuring that your secrets are safeguarded during both storage and transmission.

In Azure, encryption at rest is implemented across various services using AES 256 encryption, while data in transit is secured through TLS and MACsec to prevent unauthorized access during transmission. These encryption practices provide comprehensive protection for your data, whether it’s being stored or transmitted between systems. For more details, see Encryption at rest and in transit.

Safe distribution of secrets

When distributing secrets, ensure they are shared securely within and outside the organization. Use tools designed for secure sharing and include secret recovery procedures in your disaster recovery plans. If a key is compromised or leaked, it should be regenerated immediately. To further enhance security, use distinct keys for each consumer rather than sharing keys, even if they have similar access patterns. This practice simplifies key management and revocation, ensuring that compromised keys can be revoked without affecting other consumers.

Service-specific best practices

Individual services may have additional best practices and guidance for protecting secrets. Here are some examples:

Next steps

Minimizing security risk is a shared responsibility. You need to be proactive in taking steps to secure your workloads. Learn more about shared responsibility in the cloud.

See Azure security best practices and patterns for more security best practices to use when you're designing, deploying, and managing your cloud solutions by using Azure.