ADR-0005: Use SPIFFE mTLS for Inter-Component Authentication and Communication

Status: accepted
Date: 2024-11-03
Tags: Security, Networking, SPIFFE, SPIRE

Context

Our system requires secure communication between various components with:

Strong mutual authentication
Network-level security
Identity management for services
Automated certificate management
Zero-trust security model

Current challenges in service-to-service authentication include:

Managing service identities
Certificate distribution and renewal
Secure communication channels
Identity verification between components

Decision

We will implement SPIFFE with mTLS for all inter-component communication and authentication:

Authentication Mechanism:
- Use SPIFFE SVIDs (SPIFFE Verifiable Identity Document) for component identification
- Implement mutual TLS (mTLS) for all service-to-service communication
Identity Management:
- Each component will be assigned a unique SPIFFE ID
- Components will authenticate using their SVIDs
Security Layer:
- Network security will be handled at the TLS layer using SPIFFE-issued certificates
- All communication will be encrypted using mTLS

Consequences

Positive

Strong cryptographic identity for each workload
Automated certificate management
Zero-trust security model implementation
Dynamic identity provisioning
Reduced operational overhead for certificate management
Platform-agnostic identity management
Standardized authentication mechanism
Automatic certificate rotation
No shared secrets required

Negative

Additional system complexity
Need for SPIFFE infrastructure maintenance
Performance overhead from TLS handshakes
Need to manage SPIFFE deployment and updates

Implementation Requirements

Infrastructure

Deploy SPIFFE/SPIRE server
Configure workload attestation
Set up certificate authority integration

Component Integration

Implement SPIFFE workload API in all components
Configure mTLS endpoints
Implement SVID verification

Security Considerations

Secure SPIFFE control plane
Configure proper attestation policies
Implement certificate rotation policies
Monitor SVID lifecycle

Monitoring and Maintenance

Monitor certificate expiration
Track authentication failures
Audit identity assignments
Monitor SPIFFE infrastructure health

Recovery Procedures

Certificate Issues

Automated SVID renewal
Manual SVID regeneration procedures
Fallback authentication methods

Infrastructure Issues

SPIFFE server redundancy
Backup attestation procedures
Emergency access procedures

References

Notes

Regular security audits should verify the correct implementation of SPIFFE/mTLS configurations and assess the effectiveness of the authentication mechanisms.