product-infrastructure-security-engineer

name: product-infrastructure-security-engineer description: | Guides product infrastructure security—securing the runtime, data plane, and control plane that ships with the product: multi-tenant isolation, service-to-service auth, customer data boundaries, secure defaults in APIs and workers, abuse-resistant rate limits, product-scoped secrets and encryption, and security design reviews for product infra changes. Use when threat-modeling product features, designing tenant isolation, hardening service mesh or internal APIs, reviewing product IaC/modules for data leaks, defining secure baselines for microservices the product team owns, or partnering on incidents affecting customer workloads—not for corporate IdP/SIEM (information-security-engineer), CI pipeline gates only (devsecops), SOC operations (defensive-security-analyst), authorized pentest execution (offensive-security-analyst), general IDP golden paths (platform-engineer), company-wide GRC (cybersecurity), or applied AI solution architecture for LLM features (applied-ai-architect-commercial-enterprise).

Product Infrastructure Security Engineer

When to Use

• Threat-model product features, internal APIs, workers, and customer-facing infrastructure
• Design or review tenant isolation, authorization boundaries, and customer data-plane controls
• Harden product-owned services with secure defaults, service auth, rate limits, audit logs, and encryption
• Review product IaC or runtime changes for cross-tenant data leaks and abuse paths
• Support incidents involving customer workloads, tenant blast radius, or product security regressions

When NOT to Use

• Implement corporate IdP, KMS, PAM, SIEM, or EDR systems → information-security-engineer
• Add CI/CD security gates, SBOMs, or supply-chain controls only → devsecops
• Run SOC alert triage and detection tuning → defensive-security-analyst
• Execute authorized pentests or exploit validation → offensive-security-analyst
• Build general IDP, golden paths, or developer portals → platform-engineer
• Define company-wide security strategy or GRC roadmap → cybersecurity
• Design RAG/copilot/LLM solution architecture → applied-ai-architect-commercial-enterprise

Related skills

Core Workflows

1. Product threat modeling

Scope the product boundary (what attackers and tenants can reach):

1. List actors: customer user, tenant admin, partner integration, internal operator, anonymous
2. Map assets: customer data, credentials, billing, config, audit logs
3. Draw data flows across services and stores
4. Identify trust boundaries (tenant, region, env)
5. Prioritize threats: cross-tenant access, privilege escalation, data exfil, abuse
6. Record mitigations and residual risk owners

See references/product_threat_model.md for STRIDE-lite worksheet.

2. Multi-tenant isolation

Isolation goals:

• No cross-tenant read/write on data paths
• Blast radius contained per tenant on compromise
• Strong tenant ID in every authZ decision (never trust client-supplied tenant alone)

Patterns: row-level security, per-tenant keys, namespace isolation, dedicated cells for enterprise tier.

See references/multi_tenant_isolation.md for patterns and test cases.

3. Service and API security baselines

Every product service should default to:

• Authenticated internal calls (mTLS or signed service tokens)
• AuthZ at resource level, not only route level
• Input validation and size limits on APIs
• Structured audit logs for security-relevant actions
• No secrets in images; workload identity for cloud APIs

See references/secure_service_defaults.md for checklist and anti-patterns.

4. Customer data protection

See references/customer_data_protection.md for key hierarchy and deletion workflow.

5. Abuse and resilience

• Rate limits per tenant/user/IP on public and partner APIs
• Idempotency and replay protection on sensitive mutations
• Circuit breakers on dependency calls that handle tenant context
• Quotas on expensive operations (exports, bulk API)

Align with defensive monitoring for anomaly signals.

6. Security design review (product infra)

Review triggers: new data store, new cross-service API, tenancy model change, new integration surface, crypto change.

Review output:

• Findings with severity
• Required controls before launch
• Test plan (isolation tests, negative authZ cases)
• Rollback / feature flag recommendation

See references/security_design_review.md for review template.

7. Incident support (product scope)

When customer workloads are affected:

1. Confirm blast radius (which tenants, regions)
2. Preserve tenant-scoped logs and configs
3. Coordinate containment without cross-tenant impact
4. Post-incident: add regression test and detection

Hand off enterprise IR/comms to cybersecurity when required.

When to load references

• Threat modeling → references/product_threat_model.md
• Tenancy → references/multi_tenant_isolation.md
• Service baselines → references/secure_service_defaults.md
• Data and crypto → references/customer_data_protection.md
• Design reviews → references/security_design_review.md