When Six STRIDE Categories Meet Five Defensive Layers
STRIDE איום modeling: Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege. Microsoft's six-category taxonomy for systematic איום analysis. Industry-standard. Battle-tested. Comprehensive—allegedly.
Here's where numerology meets reality: Mapping STRIDE to the CIA Compliance Manager architecture revealed six categories compressing into five defensive requirements. Denial of Service? Defeated by architectural simplicity (static hosting eliminates 90% of DoS משטח תקיפה). The remaining five threats align perfectly with five defensive layers. Coincidence? Or the universe revealing optimal security structure through constraint?
Challenge conventional security thinking: More איום categories don't guarantee comprehensive defense. Overlapping categories create false coverage confidence. Our five-layer defense addresses all six STRIDE threats because layers are orthogonal—each protecting fundamentally different משטח תקיפהs. Pattern recognition enabling defensive efficiency over exhaustive categorization.
Illumination: Six STRIDE categories mapping to five defenses reveals which threats share root causes. Spoofing + Elevation of Privilege both defeated by authentication. Tampering + Repudiation both defeated by שלמות controls. Pattern recognition enabling defensive efficiency.
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The Client-Side Security Advantage
Conventional ציות tools: server-side SaaS. Users upload sensitive data. Vendor stores it. Vendor secures it. Vendor sells "enterprise security" as competitive advantage.
We chose differently. Client-side application. IndexedDB storage. No backend. Data never leaves user's browser. Attack surface: minimal. Why?
Five advantages of client-side architecture for ציות:
- Zero Server Vulnerabilities: No SQL injection (no SQL server). No RCE (no command execution). No SSRF (no server-side requests). No XXE (no XML parsing). Entire OWASP Top 10 mostly irrelevant. Attack surface collapsed.
- Data Sovereignty By Default: User data in user's browser on user's device under user's control. No "our privacy policy says..." marketing. Mathematical privacy through architecture. GDPR ציות automatic.
- Offline Operation: Internet down? ציות assessment continues. Network compromised? Sensitive data already local. Air-gapped environments? Install once, run forever. Resilience through independence.
- אבטחה שקופה: JavaScript בצד הלקוח מאפשר למשתמשים לבדוק את האבטחה. צפו בקוד המקור. קראו את הקוד. אמתו יישומים קריפטוגרפיים. אמון דרך אימות, לא הבטחות ספק.
- Cost Reduction: No server costs = $0/month hosting. GitHub Pages free. CloudFlare free tier. Zero hosting fees enabling free open-source tool. Economic sustainability through architectural simplicity.
Tradeoffs acknowledged: No server = no real-time collaboration (roadmap: peer-to-peer via WebRTC). No centralized backup (roadmap: encrypted cloud export). Client-side limits (roadmap: Web Workers for heavy computation). Honest tradeoff documentation > marketing spin.
Security architecture that eliminates entire attack classes beats security architecture defending against every attack in every class. Choose simplicity enabling security over complexity requiring security.
Client-Side Security Architecture: Defense Through Simplicity
Each security layer addresses specific איום categories. Client-side architecture fundamentally eliminates server-side attack vectors while requiring careful defense of browser-based threats.
1. 🌐 Content מדיניות אבטחה: Injection Defense
threats mitigated: Cross-site scripting (XSS), data exfiltration via injected scripts, unauthorized resource loading.
CSP directives: Restrictive policy limiting script sources, style sources, and connection endpoints. Configuration deployed via GitHub Pages headers.
React framework protection: Automatic XSS prevention through JSX escaping, DOM manipulation sanitization, and controlled prop rendering.
CSP that blocks legitimate functionality fails usability. CSP that allows everything fails security. Balance through minimum necessary directives based on actual application requirements.
2. 🔐 Subresource שלמות: Dependency Trust
איום mitigated: Compromised CDN serving malicious library versions, supply chain attacks on external dependencies.
SRI implementation: Cryptographic hash validation for external resources. Dependency שלמות verification at build time.
Supply chain verification: Dependabot automation for security updates, FOSSA license ציות scanning. Evidence: FOSSA dashboard.
3. 🛡️ Type Safety: Runtime Error Prevention
threats mitigated: Type confusion vulnerabilities, runtime errors causing denial of service, malformed data processing.
TypeScript strict mode: Comprehensive type checking with noImplicitAny, strictNullChecks, strictFunctionTypes compilation flags. Type errors block builds.
Build-time validation: ESLint static analysis, TypeScript compiler checks, Vite build optimization with tree-shaking removing unused code.
4. 🔒 Data Protection: Browser Storage Security
איום mitigated: Local storage compromise, unauthorized data access from malicious extensions or co-located attacks.
Current implementation: IndexedDB within browser sandbox. Relies on OS-level disk encryption and browser profile security for data-at-rest protection.
Future enhancement: Client-side encryption using SubtleCrypto API for additional zero-knowledge protection layer independent of OS security.
5. 👁️ Build שלמות: Supply Chain Assurance
threats mitigated: Compromised build pipeline, tampered artifacts, unauthorized code injection.
מנגנונים: CI/CD אוטומטי דרך GitHub Actions, אישורי מקור SLSA Level 3, חפצי build בלתי ניתנים לשינוי, חתימה קריפטוגרפית של שחרורים.
Validation: OpenSSF Scorecard monitoring (check current score), dependency review workflow, CodeQL security scanning.
Client-Side איום Considerations
Client-side architecture shifts איום focus from server-side attacks to browser-based vulnerabilities, DOM manipulation risks, and local storage security.
Key security considerations for ציות tools:
- XSS Prevention: React framework provides automatic escaping. Additional DOMPurify sanitization for user-generated assessment notes. CSP headers enforce restrictive script policies.
- Data סודיות: Browser sandbox isolation plus OS-level encryption. Future roadmap includes client-side encryption for additional zero-knowledge protection.
- אבטחת שרשרת אספקה: אימות SRI עבור תלויות חיצוניות. עדכוני Dependabot אוטומטיים. אישורי build SLSA Level 3 מספקים הבטחת מקור.
- Storage Security: IndexedDB access restricted to same-origin. No server-side data transmission eliminates network interception risks.
- Build Pipeline שלמות: GitHub Actions automation with security scanning. CodeQL SAST analysis. Dependency review blocking vulnerable packages.
איום modeling that honestly documents residual risk and architectural tradeoffs enables informed security decisions. Transparency about limitations builds trust more than marketing perfect security.
Supply Chain Security: Dependency Management
npm dependencies represent trust decisions. How verification works:
- License ציות: FOSSA scanning ensures MIT/Apache-2.0/BSD compatibility. Public ציות badge provides transparency.
- פגיעות Scanning: Dependabot automation generates security update PRs. GitHub dependency review workflow blocks vulnerable package introductions.
- מקור Build: אישורי SLSA Level 3 מספקים עדות קריפטוגרפית המקשרת חפצים למקור. צפו באישורים ציבוריים.
- Continuous Validation: OpenSSF Scorecard measures security practices. Check current score for branch protection, code review, and dependency update evidence.
- Static Analysis: CodeQL security scanning integrated into CI/CD. ESLint rules enforce secure coding patterns.
Dependency minimization strategy: Prefer platform APIs over libraries where practical. React core provides substantial functionality reducing external dependency requirements.
Security Roadmap: Progressive Enhancement
Security evolution planned through progressive enhancement maintaining backward compatibility while adding defense layers.
Phase 1: Enhanced Authentication
Optional OAuth integration for multi-device sync. GitHub/Google/Microsoft identity providers. Session management with secure token handling.
Phase 2: Client-Side Encryption
SubtleCrypto API integration for zero-knowledge architecture. AES-GCM encryption of assessment data. User-controlled encryption keys never transmitted.
Year 3: Audit Logging
Action log in IndexedDB. Merkle tree tamper-evidence.
Year 4: WebAuthn Biometric
Touch ID, Face ID, Windows Hello. Phishing-resistant.
Year 5: Post-Quantum Crypto
Lattice-based encryption. Quantum-resistant future-proofing.
Security Wisdom: Five Key Lessons
- Client-side = defensive advantage. No server = no server vulnerabilities.
- Six STRIDE categories → five defenses. Pattern recognition enabling focus.
- Type safety is security. Compile-time verification = pre-deployment bug elimination.
- Automated evidence > manual assurance. Cryptographic proof, not promises.
- Security roadmaps enable transparency. Show trajectory, not just snapshot.
Verify Our Security
Simon Moon, System Architect, Hack23 AB
"Client-side security is mathematical security—משטח תקיפה minimized through architectural constraint."