architecting-security_skill

Overview

This skill designs comprehensive security architectures using defense-in-depth, zero trust, structured threat modeling (STRIDE, PASTA), and mappings to control frameworks like NIST CSF, CIS Controls, and ISO 27001. It guides strategic decisions for greenfield and brownfield systems, cloud-native and hybrid environments, and supply chain protections such as SLSA and SBOM. The focus is on pragmatic, risk-based architectures and governance that scale with organizational maturity.

How this skill works

I inspect system boundaries, data flows, identity and trust relationships, and operational processes to recommend layered controls and verification points. I apply threat modeling (DFDs + STRIDE/PASTA), map mitigations to control frameworks, and produce architecture patterns for identity, segmentation, monitoring, and supply-chain hardening. Outputs include prioritized controls, implementation roadmaps (zero trust overlays, cloud multi-account patterns), and prescriptive guidance for detection and response.

When to use it

• Designing security for a new application, cloud migration, or greenfield system
• Auditing or hardening an existing architecture (brownfield) and planning progressive improvements
• Implementing zero trust across users, devices, and services
• Establishing or maturing security governance and compliance programs (NIST CSF, ISO 27001, CIS)
• Threat modeling APIs, microservices, or complex data flows to prioritize mitigations
• Securing the software supply chain with SBOMs, SLSA, and automated dependency controls

Best practices

• Adopt defense-in-depth: independent layers (network, identity, app, data, ops) with clear failure modes
• Design identity-first and least-privilege policies; enforce MFA, JIT access, and RBAC/ABAC
• Apply continuous verification: device posture, behavioral analytics, and centralized policy engines
• Prioritize controls by risk and maturity—start with CIS IG1 for baselines and map to NIST CSF
• Automate security in CI/CD: SBOM generation, dependency scanning, signed builds (SLSA progression)
• Segment and micro-segment critical assets first to limit blast radius and enable safe incident recovery

Example use cases

• Greenfield SaaS platform: identity-first architecture with zero trust, micro-segmentation, and CI/CD signing
• Enterprise brownfield: overlay zero trust controls incrementally, segment admin and data planes, modernize IAM
• Cloud multi-account strategy: Security/Logging/Audit accounts with SCPs, centralized telemetry, and CSPM
• Threat modeling sprint: DFD-led STRIDE analysis to produce prioritized mitigations tied to frameworks
• Supply-chain hardening: add SBOMs, automate vulnerability alerts, and move CI to hardened SLSA levels