slate-v3-1770514618/.sdlc/features/user-preferences/audit.md

Security Audit: User Preferences API

Summary

Overall Assessment: PASS

The User Preferences API feature demonstrates solid security practices. No critical or high severity findings were identified. The implementation correctly enforces authentication via JWT middleware, performs authorization checks (own-user or admin), validates all inputs at appropriate layers, and avoids common vulnerability patterns. A few medium/low observations are noted for future hardening.

Static Analysis Results

• go vet ./...: Clean — no warnings or errors
• All tests passing: 30/30 tests pass across domain, adapter, service, and handler layers
• No golangci-lint available in the environment; go vet was the sole static analyzer run

OWASP Assessment

Category	Status	Notes
A01: Broken Access Control	PASS	Authorization enforced in handler layer via authorizeAccess(). Users can only access own preferences unless they have admin role. Tested with forbidden and admin-access test cases.
A02: Cryptographic Failures	PASS	No sensitive data stored. Preferences contain no PII beyond user_id. JWT secret sourced from environment variable, not hardcoded.
A03: Injection	PASS	No SQL queries, command execution, or template rendering. All data is in-memory Go maps. JSON input is parsed via standard encoding/json with manual key allowlisting.
A04: Insecure Design	PASS	Hexagonal architecture cleanly separates concerns. Domain validation prevents invalid state. Merge semantics use pointer fields to distinguish present vs absent values.
A05: Security Misconfiguration	PASS (with note)	Auth is configurable via AUTH_ENABLED env var. When disabled, the authorizeAccess() function allows all access (returns nil when no auth user in context). This is the intended local-dev behavior but warrants documentation. No debug modes exposed.
A06: Vulnerable Components	PASS	Uses standard Go stdlib encoding/json, regexp, sync. External deps: chi/v5 (router), google/uuid (UUID parsing) — both well-maintained.
A07: Auth Failures	PASS	JWT middleware from pkg/auth handles token extraction and validation. Unauthenticated requests are blocked before reaching handler code (when auth is enabled).
A08: Software/Data Integrity	PASS	No deserialization of untrusted types. JSON decoding targets known structs with explicit field tags. Unknown fields in preferences are rejected via manual key allowlisting.
A09: Logging & Monitoring Gaps	PASS (with note)	Service layer logs successful upserts with user_id. However, failed authorization attempts are not explicitly logged (they return httperror.Forbidden which is handled by the framework). Failed validation is also not logged at the service level.
A10: SSRF	PASS	No outbound HTTP calls, no user-controlled URLs, no network access from this service.

Critical Findings

None.

High Findings

None.

Medium Findings

M1: No Request Body Size Limit

Severity: Medium Location: internal/api/handlers/preferences.go:117-123 (Update handler)

The httpresponse.DecodeJSON() call does not enforce a maximum request body size. Neither the handler nor the shared pkg/httpresponse package uses http.MaxBytesReader. An attacker could send an arbitrarily large JSON payload to exhaust server memory.

Risk: Denial-of-service via oversized request bodies.

Remediation: Apply http.MaxBytesReader(w, r.Body, maxBytes) before decoding, either in the handler or as framework middleware. A reasonable limit for preferences would be 64KB.

Note: This is a framework-level concern shared across all services, not specific to this feature.

M2: Auth Bypass When AUTH_ENABLED=false

Severity: Medium Location: internal/api/routes.go:29, internal/api/handlers/preferences.go:183-192

When AUTH_ENABLED is false (default), the auth middleware is not applied. The authorizeAccess() function handles this by checking if user == nil { return nil } — allowing all requests through without any authorization check. This means any caller can read/write any user's preferences.

Risk: In a deployment where auth is accidentally left disabled, all preferences become world-readable/writable.

Remediation: This is the documented design for local development, but production deployments should enforce AUTH_ENABLED=true via deployment configuration or health-check validation. Consider logging a warning at startup when auth is disabled.

Low Findings

L1: Limited Audit Logging

Severity: Low Location: internal/service/preferences.go:57

Only successful upserts are logged. Failed authorization, validation failures, and read operations are not logged at the application level (though framework middleware may capture HTTP-level access logs).

Remediation: Add structured logging for authorization denials and validation failures at the handler layer for operational visibility.

L2: Time Format Precision

Severity: Low Location: internal/api/handlers/preferences.go:82

The UpdatedAt field is formatted with "2006-01-02T15:04:05Z" which drops sub-second precision. This is cosmetic but means two rapid updates in the same second would appear to have the same timestamp.

Remediation: Consider using time.RFC3339Nano or at least millisecond precision if needed for conflict detection in future.

Recommendations

1. Add request body size limiting — Apply http.MaxBytesReader at the framework level or per-handler (Medium priority)
2. Log a warning when auth is disabled — Make it obvious in startup logs that the service is running without authentication (Medium priority)
3. Add audit logging for authz failures — Log when authorization checks reject a request, including the requesting user ID and target user ID (Low priority)
4. Document AUTH_ENABLED behavior — Ensure deployment runbooks require AUTH_ENABLED=true in production (Low priority)

Files Reviewed

File	Lines	Reviewed
internal/domain/preferences.go	113	Yes
internal/domain/errors.go	11	Yes
internal/domain/preferences_test.go	211	Yes
internal/port/preferences.go	17	Yes
internal/adapter/memory/preferences.go	50	Yes
internal/adapter/memory/preferences_test.go	73	Yes
internal/service/preferences.go	59	Yes
internal/service/preferences_test.go	153	Yes
internal/api/handlers/preferences.go	210	Yes
internal/api/handlers/preferences_test.go	303	Yes
internal/api/routes.go	42	Yes
internal/api/spec.go	89	Yes
internal/config/config.go	34	Yes
cmd/server/main.go	39	Yes
pkg/auth/middleware.go	234	Yes (shared)
pkg/auth/auth.go	92	Yes (shared)
pkg/httpresponse/response.go	193	Yes (shared)