dsfx/docs/adr/0014-auditability-logging-and-security-monitoring.md

ADR-0014: Auditability, Logging, and Security Monitoring

Status

Proposed

Context

Our system is built on the core principles of user control, transparency, and data integrity. For users to trust that their data is secure and managed correctly, all file operations and node interactions must be auditable and subject to thorough logging. In addition, security monitoring is paramount to quickly detect anomalies, tampering, or breaches. This ADR addresses the need to design an audit trail and security monitoring framework that satisfies the following:

• Functional requirements (FR-6): Every file operation, version change, and node interaction must be logged in a tamper-evident manner to support auditability and transparency.
• Non-functional requirements (NFR-1, NFR-2, NFR-5, NFR-6): Security and privacy mandates that logs must be secured and verified, while performance and maintainability indicators require that logging mechanisms impose minimal overhead. The framework must also integrate with deterministic simulation testing so that logging and security events can be consistently reproduced under simulated adverse conditions.

The logging framework must be designed not only to record normal operations but to flag and alert on aberrant activities, ensuring robust security monitoring across all system components.

Decision

We will implement a comprehensive logging and security monitoring solution with the following components:

• Append-Only Logging: All system operations—including file uploads/downloads, manifest updates, conflict resolutions, and node interactions—will be recorded in an immutable, append-only log. This log will be cryptographically chained (see ADR-0006) to help ensure tamper-evidence and to maintain a verifiable history of system events.

• Granular Audit Trails: Logs will capture key metadata for each operation, including timestamps, device identifiers, user and node credentials, and the outcome of operations. These detailed audit trails provide full transparency and support retrospective security investigations (FR-6).

• Real-Time Security Monitoring: A monitoring component will actively analyze log entries and system events in real time to detect anomalous behavior, potential tampering, or security breaches. Automated alerting mechanisms will notify administrators when suspicious activity is detected, enabling rapid response in line with our security and privacy requirements (NFR-1).

• Integration with Deterministic Simulation: The logging and monitoring framework will support deterministic simulation testing. This capability allows us to replay logged events under simulated network or disk failure conditions, ensuring that the logging system consistently captures and reports events, even under adverse operating conditions (NFR-2, NFR-6).

• Secure Log Storage: Logs will be stored in a secure manner using encryption at rest and in transit. Access controls will ensure that log data is only available to authorized entities, further protecting sensitive audit information in compliance with our privacy requirements.

Consequences

• Advantages:

  • Enhanced Transparency and Trust: A robust, tamper-evident logging solution supports full auditability, empowering users to verify that all operations are performed in accord with security policies.
  • Improved Security Posture: Real-time monitoring and alerting enable quick detection and remediation of anomalies or intrusions, reinforcing our overall security and privacy framework (NFR-1).
  • Consistent Auditing Across Conditions: Integration with deterministic simulation testing ensures that logging remains reliable and verifiable even under simulated adverse network or disk conditions (NFR-2, NFR-6).
  • Regulatory Compliance: Detailed audit trails facilitate compliance with security standards and legal requirements for data handling and breach notifications.

• Trade-offs:

  • Performance Impact: Comprehensive logging and real-time monitoring can add overhead in terms of processing and storage. However, careful optimization and the use of asynchronous logging techniques will help mitigate this impact.
  • Complexity in Log Management: Ensuring that log data remains secure, accessible, and tamper-evident over time requires robust management strategies and additional development effort.
  • Data Volume: Detailed logs can grow rapidly in size, which necessitates strategies for log rotation, archival, and secure deletion to avoid storage bloat.

References to Requirements

• Functional Requirements:

  • FR-6: Auditability and Access Management require that every operation is logged in a verifiable manner.

• Non-Functional Requirements:

  • NFR-1: Security & Privacy – Secure, encrypted log storage and access controls are essential components.
  • NFR-2: Performance & Responsiveness – The logging system must operate efficiently even under adverse conditions.
  • NFR-5: Auditability & Transparency – The design directly supports complete audit trails and tamper-evident logging.
  • NFR-6: Deployability & Maintainability – Integration with deterministic simulation testing ensures that the logging and monitoring mechanisms are both testable and maintainable.

Conclusion

Implementing a comprehensive auditability, logging, and security monitoring framework is essential for building trust in our self-hosted file storage system. By adopting an immutable, chained logging strategy combined with real-time security monitoring and integration with deterministic simulation testing, we ensure that all actions on the system are transparent and verifiable. This approach aligns with our core functional and non-functional requirements, ensuring that our system remains secure, reliable, and fully under user control.