Skip to content

MAS Security

Based on OWASP MAESTRO v1.0 – a 7-layer threat modeling framework for multi-agent systems.

MAESTRO Layers

Layer Focus Key Concern
1. Model LLM security Prompt injection, data leakage
2. Agent Logic Agent behavior Input validation, type safety
3. Integration External services Service failures, API key exposure
4. Monitoring Observability Log injection, sensitive data in traces
5. Execution Runtime safety Resource exhaustion, race conditions
6. Environment Infrastructure Container isolation, secret mgmt
7. Orchestration Coordination Registration hijacking, exec order

Layer Threats and Mitigations

Layer 1: Model

Threat Mitigation
Prompt injection Structured outputs with schema validation
Model poisoning Provider abstraction; no direct model API calls
Data leakage Output validation; content filtering

Layer 2: Agent Logic

Threat Mitigation
Unvalidated inputs Typed models at all component boundaries
Type confusion ABC/interface contracts enforcing signatures
Logic bugs in coordination Explicit typed context passing

Layer 3: Integration

Threat Mitigation
Service downtime cascade Timeouts; graceful degradation w/ partials
API key leakage Credentials from env vars (12-Factor #3)
Compromised external service Rate limits; circuit breakers; retry/backoff

Layer 4: Monitoring

Threat Mitigation
Log injection Structured logging; no string interpolation
Trace data tampering Immutable event streams; append-only stores
Sensitive data in logs No PII in default output; log sanitization

Layer 5: Execution

Threat Mitigation
Resource exhaustion Per-component timeouts; memory limits
Infinite loops Timeout enforcement; bounded iteration
Race conditions Stateless design; thread-safe external stores

Layer 6: Environment

Threat Mitigation
Container escape Non-root execution; read-only filesystems
Secret exposure .env excluded from VCS; external vault
Network attacks Network segmentation; minimal exposed ports

Layer 7: Orchestration

Threat Mitigation
Registration hijacking Static imports; no dynamic plugin loading
Execution order tampering Explicit ordering in code, not configuration
Unauthorized components Allowlists; signature verification

Threat Matrix Template

Layer Component Threat Severity Mitigation Status
1 (Model) LLM caller Prompt injection HIGH Structured out
2 (Logic) Agent interface Type confusion MED Schema valid
3 (Integration) External APIs Service down MED Graceful degrade
4 (Monitoring) Trace store Log injection MED Structured log
5 (Execution) Runner Resource exhaust HIGH Timeouts
6 (Environment) Infrastructure Secret exposure HIGH Env var mgmt
7 (Orchestration) Registry Unauthorized MED Static imports

Security Checklist

For design quality checks, see the Design Checklist.

Input Validation

  • All inputs validated via typed model schema
  • String inputs sanitized (no code injection)
  • Numeric inputs range-checked
  • File paths validated (no directory traversal)

Output Safety

  • Outputs use typed validated models
  • No sensitive data in outputs (PII, API keys)
  • Error messages don’t leak internal state
  • Structured errors for graceful degradation

Resource Management

  • Timeouts configured per component
  • Memory usage bounded (no unbounded collections/loops)
  • File descriptors properly closed
  • Network connections have timeouts

Observability

  • Structured logging with context
  • Trace events emitted for debugging
  • No sensitive data in logs
  • Error paths logged for audit

External Dependencies

  • API keys from environment variables
  • External service failures handled gracefully
  • Retry logic with exponential backoff
  • Circuit breaker for cascading failures

References