Skip to content

Latest commit

 

History

History
100 lines (87 loc) · 15.1 KB

mitigations.md

File metadata and controls

100 lines (87 loc) · 15.1 KB

Mitigation Strategies Analysis for google/tink

Mitigation Strategy: Secure Key Generation using Tink APIs

  • Description:
    1. Utilize Tink's Key Generation API: Developers should exclusively use Tink's provided KeyGenerator classes and KeyTemplate mechanisms (e.g., AesGcmKeyManager.keyTemplate(), KeyGenerator.generate(KeyTemplate)). This ensures keys are generated using cryptographically sound methods provided by Tink.
    2. Leverage Tink Key Templates: Always define and use KeyTemplate objects to specify the desired cryptographic algorithm, key size, and other parameters when generating keys with Tink. This enforces consistent and secure key generation configurations as recommended by Tink.
    3. Avoid External Key Generation: Do not use external or custom key generation methods outside of Tink's API when managing keys intended for use with Tink primitives. Rely on Tink's managed key generation to maintain compatibility and security guarantees.
  • Threats Mitigated:
    • Weak Key Generation due to Custom Methods (High Severity): If developers use custom or insecure key generation methods instead of Tink's, it can lead to cryptographically weak keys easily broken by attackers.
    • Incompatible Key Formats (Medium Severity): Generating keys outside of Tink's framework might result in keys that are not compatible with Tink's primitives, leading to implementation errors and potential security issues.
  • Impact:
    • Weak Key Generation due to Custom Methods: High Risk Reduction - By enforcing the use of Tink's key generation, the risk of weak keys is significantly reduced, making attacks much harder.
    • Incompatible Key Formats: Medium Risk Reduction - Ensures keys are in the correct format for Tink, preventing integration issues and potential vulnerabilities arising from incorrect key handling.
  • Currently Implemented: Yes, key generation for encryption keys within the EncryptionService utilizes AesGcmKeyManager.keyTemplate() and Tink's KeyGenerator.
  • Missing Implementation: Ensure all key generation throughout the application, especially for any new cryptographic operations, strictly adheres to Tink's API and KeyTemplate usage. Review any legacy code for potential non-Tink key generation and migrate to Tink's methods.

Mitigation Strategy: Secure Key Storage using Tink's KMS Integration

  • Description:
    1. Utilize Tink's KMS Integration: Leverage Tink's built-in support for Key Management Systems (KMS) through classes like KmsAeadKeyManager and KmsEnvelopeAead. This allows Tink to interact with KMS services (like AWS KMS, Google Cloud KMS, Azure Key Vault) for secure key wrapping and storage.
    2. Encrypt Keyset Handles with KMS: When persisting KeysetHandle objects, always encrypt them using a KMS-managed key via Tink's KMS integration (e.g., keysetHandle.write(..., kmsAead)). This ensures keys are protected at rest by the KMS.
    3. Configure Tink with KMS URI: Properly configure Tink with the correct KMS URI and credentials to enable communication with the chosen KMS provider. Ensure these configurations are securely managed and not exposed in code.
  • Threats Mitigated:
    • Key Compromise due to Insecure Storage (Critical Severity): Storing Tink keys directly in files, databases, or configuration without KMS protection makes them vulnerable to theft if these storage locations are compromised.
    • Lack of Key Management Features (Medium Severity): Without KMS integration, applications miss out on KMS features like access control, auditing, and centralized key management, increasing the risk of unauthorized key access or misuse.
  • Impact:
    • Key Compromise due to Insecure Storage: High Risk Reduction - KMS provides a hardened, auditable, and access-controlled environment for key storage, drastically reducing the risk of key compromise. Tink's KMS integration makes leveraging KMS straightforward.
    • Lack of Key Management Features: Medium Risk Reduction - Gains the benefits of centralized key management, access control, and auditing provided by KMS, enhancing overall key security posture through Tink's integration.
  • Currently Implemented: Partially. The application uses KmsAeadKeyManager and AWS KMS for wrapping encryption keys used for database encryption.
  • Missing Implementation: Verify that all Tink keys used in the application are protected by KMS integration. Ensure KMS URI and credentials are managed securely (e.g., environment variables, secrets management) and not hardcoded. Review if signing keys (if used) are also KMS-protected via Tink.

Mitigation Strategy: Implement Key Rotation using Tink's Keyset Management

  • Description:
    1. Utilize Tink's KeysetHandle for Rotation: Leverage Tink's KeysetHandle to manage keysets, which inherently supports key rotation. KeysetHandle can contain multiple keys, allowing for smooth transitions during rotation.
    2. Programmatic Key Rotation with Tink: Implement a programmatic key rotation process using Tink's API. This might involve generating a new key using KeyGenerator, adding it to the KeysetHandle as the primary key, and potentially deactivating older keys after a transition period.
    3. Understand Tink's Key Versioning: Be aware of Tink's key versioning within KeysetHandle and how it impacts key selection for encryption and decryption. Ensure rotation logic correctly handles key versions and transitions.
  • Threats Mitigated:
    • Long-Term Key Compromise (Medium to High Severity): Even with secure storage, keys can become vulnerable over time. Key rotation limits the lifespan of keys, reducing the window of opportunity for attackers. Tink's keyset management is designed to facilitate rotation.
    • Impact of Single Key Compromise (High Severity): If a single, long-lived key is compromised, all data encrypted with it is at risk. Rotation limits the scope of damage by ensuring data is encrypted with different keys over time, a feature directly supported by Tink's keysets.
  • Impact:
    • Long-Term Key Compromise: Medium Risk Reduction - Reduces the likelihood of long-term key compromise by enforcing periodic key changes, a process made manageable by Tink's keyset features.
    • Impact of Single Key Compromise: Medium Risk Reduction - Limits the amount of data compromised if a key is exposed, as older data will be encrypted with different keys managed within Tink's keyset.
  • Currently Implemented: No. Key rotation is not currently implemented using Tink's keyset management features. Keys are generated once and not rotated.
  • Missing Implementation: Key rotation logic needs to be implemented using Tink's KeysetHandle. This includes:
    • Developing a rotation schedule and integrating it with Tink's keyset management.
    • Implementing the programmatic key rotation steps using Tink's API.
    • Ensuring the application's encryption/decryption logic correctly utilizes KeysetHandle for key version handling during rotation.

Mitigation Strategy: Correct Tink Primitive Selection and Configuration

  • Description:
    1. Choose Tink Primitives Based on Security Needs: Carefully select Tink primitives (e.g., Aead, Mac, Signature) that precisely match the required security functionality (encryption, authentication, signing). Refer to Tink's documentation for guidance on primitive selection.
    2. Utilize Tink's Recommended Key Templates: Favor Tink's recommended KeyTemplate presets for each primitive. These templates represent secure and vetted configurations for common cryptographic tasks.
    3. Avoid Custom or Non-Standard Configurations: Unless there is a very specific and well-justified reason, avoid creating custom KeyTemplate configurations or deviating from Tink's recommended settings. Non-standard configurations can introduce unexpected vulnerabilities.
    4. Consult Tink Documentation for Best Practices: Always refer to Tink's official documentation and security guidelines for best practices on primitive selection and configuration.
  • Threats Mitigated:
    • Cryptographic Misuse due to Incorrect Primitive Choice (High Severity): Using the wrong Tink primitive for a security task (e.g., using Mac for encryption) can lead to complete failure of the intended security mechanism.
    • Weak Configuration due to Custom Settings (Medium to High Severity): Creating custom KeyTemplate configurations without sufficient cryptographic expertise can result in weaker or insecure cryptographic setups compared to Tink's recommendations.
  • Impact:
    • Cryptographic Misuse due to Incorrect Primitive Choice: High Risk Reduction - Ensures the application uses the correct cryptographic tools for each security requirement, preventing fundamental design flaws. Tink's documentation aids in correct selection.
    • Weak Configuration due to Custom Settings: Medium Risk Reduction - By adhering to Tink's recommended templates, the risk of introducing vulnerabilities through poorly configured cryptography is minimized.
  • Currently Implemented: Yes. The application uses Aead for encryption and Mac for authentication, primitives selected based on security requirements and reviewed against Tink's recommendations during design. Recommended KeyTemplate presets are used.
  • Missing Implementation: Ongoing vigilance is needed to ensure that any new cryptographic implementations or modifications continue to use Tink primitives and recommended templates correctly. Regular security reviews should specifically check primitive selection and configuration against Tink's best practices.

Mitigation Strategy: Regularly Update Tink Dependency

  • Description:
    1. Monitor Tink Releases: Actively monitor the official Tink project (e.g., GitHub releases, mailing lists) for new version announcements, especially security updates and patches.
    2. Update Tink Promptly: Apply updates to the Tink library dependency in the application as soon as feasible after new releases, prioritizing security patches.
    3. Use Dependency Management Tools: Utilize dependency management tools (like Maven, Gradle, npm, pip) to streamline the process of updating the Tink dependency and managing transitive dependencies.
    4. Test After Updates: Thoroughly test the application's cryptographic functionality after updating Tink to ensure compatibility and that no regressions have been introduced by the update.
  • Threats Mitigated:
    • Exploitation of Known Tink Vulnerabilities (Critical to High Severity): Outdated versions of Tink may contain publicly known security vulnerabilities that attackers can exploit. Updating Tink patches these vulnerabilities.
    • Unpatched Security Issues (Medium to High Severity): Using older versions of Tink means missing out on potential security improvements and bug fixes included in newer releases, increasing the risk of encountering and being vulnerable to unpatched issues.
  • Impact:
    • Exploitation of Known Tink Vulnerabilities: High Risk Reduction - Applying updates eliminates known attack vectors present in older Tink versions, directly reducing the risk of exploitation.
    • Unpatched Security Issues: Medium Risk Reduction - Staying up-to-date with Tink reduces the likelihood of encountering and being vulnerable to security issues that have been addressed in newer versions.
  • Currently Implemented: Yes. Dependency management is in place using Maven, and dependency scanning is automated.
  • Missing Implementation: The process for acting on Tink updates, especially security updates, needs to be more proactive and faster. Automated alerts for new Tink releases and security advisories should be implemented to ensure timely updates.

Mitigation Strategy: Security Code Reviews Focused on Tink API Usage

  • Description:
    1. Dedicated Tink Security Review Section: Incorporate a specific section in code review checklists that focuses on secure Tink API usage. This section should cover key generation, key storage (especially KMS integration), primitive selection, and correct API parameterization.
    2. Cryptographic Expertise in Reviews: Involve developers with cryptographic knowledge or security expertise in code reviews, particularly for code sections that utilize Tink. Their expertise is crucial for identifying subtle security flaws related to Tink usage.
    3. Static Analysis for Tink Misuse: Utilize static analysis tools configured to detect common Tink API misuse patterns, insecure configurations, or deviations from Tink's best practices.
    4. Focus on Key Handling Code: Pay particular attention during reviews to code that handles KeysetHandle objects, key material, and KMS interactions. Key management code is often the most critical from a security perspective.
  • Threats Mitigated:
    • Cryptographic Misconfiguration due to Developer Error (High Severity): Developers might misconfigure Tink APIs or make mistakes in their usage, leading to exploitable vulnerabilities. Code reviews can catch these errors before deployment.
    • Key Management Flaws Introduced in Code (Critical Severity): Errors in code related to key handling are particularly dangerous. Reviews focused on Tink usage can identify and prevent critical key management vulnerabilities.
    • Subtle API Misuse Leading to Weak Security (Medium Severity): Even seemingly minor misuses of Tink APIs can sometimes lead to subtle security weaknesses that are hard to detect without careful review.
  • Impact:
    • Cryptographic Misconfiguration due to Developer Error: High Risk Reduction - Code reviews act as a crucial safety net, catching configuration errors and API misuse before they become live vulnerabilities.
    • Key Management Flaws Introduced in Code: High Risk Reduction - Focused reviews on key handling code significantly reduce the risk of critical key management vulnerabilities slipping through.
    • Subtle API Misuse Leading to Weak Security: Medium Risk Reduction - Expert reviews can identify and address subtle API misuse issues that might otherwise be missed, improving overall security robustness.
  • Currently Implemented: Yes. Security code reviews are performed, and general security aspects are considered.
  • Missing Implementation: Enhance the code review process with a more detailed checklist specifically for Tink API usage and security best practices. Provide training to developers on secure Tink usage to improve their ability to identify potential issues during reviews. Consider incorporating static analysis tools specifically tailored to detect Tink misuse patterns.