Hands-On Security Hardening Lab and Phase Exit TaskFlow - Full Stack Developer 2026
Lab 1 - Headers • Install @fastify/helmet 13.1.1 and inspect API response headers.
• Add a conservative Next.js header baseline and verify using browser DevTools/curl.
• Document a CSP plan instead of enabling an untested permissive policy.
Lab 2 - Abuse controls • Install/configure @nestjs/throttler 6.5.0.
• Create a tighter policy for an expensive endpoint.
• Test 429 behavior and confirm proxy IP handling in the deployment topology.
Lab 3 - Attack-oriented tests • Cross-workspace Task ID -> never returns foreign data.
• Unknown write fields / oversized strings -> rejected.
• Forbidden role escalation -> denied.
• Unsafe upload type/oversize -> rejected before READY.
• Public 500 response -> no stack/secret leakage.
• Logout -> QueryClient private data cleared.
Phase exit checklist • I can explain the difference between XSS, CSRF and CORS in TaskFlow.
• I know where security headers apply and why CSP needs deployment-specific testing.
• I can distinguish rate limiting from authorization.
• I know which secrets must never reach the browser or logs.
• I can threat-model an attachment upload.
• I can point to tests/evidence for tenant isolation and authorization.
• I can use ASVS as a verification baseline rather than a checkbox score.
Sources Source Purpose
OWASP ASVS 5.0.0 Security verification baseline; use explicit version references. https://owasp.org/projects/asvs
OWASP Input Validation Allowlist-oriented server validation, length/range checks and https://cheatsheetseries.owasp.org/cheatsheets/Input_Validation_ structured formats. Cheat_Sheet.html
OWASP XSS Prevention Framework escaping, dangerous sinks, output encoding and https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Script HTML sanitization. ing_Prevention_Cheat_Sheet.html
OWASP CSRF Prevention SameSite, Fetch Metadata, safe methods and CSRF controls for https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Reque ambient credentials. st_Forgery_Prevention_Cheat_Sheet.html
OWASP HTTP Headers CSP, frame protection, nosniff and related browser security https://cheatsheetseries.owasp.org/cheatsheets/HTTP_Headers_C headers. heat_Sheet.html
OWASP REST Security HTTPS, endpoint access control, JWT claims, 429, safe error https://cheatsheetseries.owasp.org/cheatsheets/REST_Security_C handling. heat_Sheet.html
OWASP File Upload Allowlisted types, generated filenames, size limits, authorization https://cheatsheetseries.owasp.org/cheatsheets/File_Upload_Che and scanning. at_Sheet.html
OWASP Logging Do not log access tokens, passwords, DB connection strings or https://cheatsheetseries.owasp.org/cheatsheets/Logging_Cheat_S encryption keys. heet.html
OWASP Secrets Management Rotation, revocation, expiration and avoiding hardcoded secrets. https://cheatsheetseries.owasp.org/cheatsheets/Secrets_Manage ment_Cheat_Sheet.html
NestJS Rate Limiting @nestjs/throttler setup, proxy handling and trackers. https://docs.nestjs.com/security/rate-limiting
@fastify/helmet Fastify 5 compatible security-header plugin; current stable https://www.npmjs.com/package/@fastify/helmet 13.1.1.
@nestjs/throttler Current stable 6.5.0; default in-memory tracker with alternate https://www.npmjs.com/package/@nestjs/throttler storage support.
Next.js Support Policy Next.js 16 is Active LTS; supported releases receive security https://nextjs.org/support-policy updates.
Security work starts with trust boundaries and abuse cases. A feature is incomplete until unauthorized and malformed paths are deliberately exercised.
Restate the goal of “Hands On Lab and Phase Exit” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: asset → trust boundary → attacker input → control → verified denial/allow. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: Security baseline checklist plus concrete tests for the most important abuse cases.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
Threat: authenticated User B changes the URL to User A's task id.
Expected control: API loads the resource scope and denies the action.
Evidence: 403 response + unchanged database row + security-safe log.Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Return to the nearest observable boundary: input, network, process log, database, or rendered UI. Compare actual evidence with the predicted path.
Change one variable at a time and reproduce the original failure after the fix; otherwise you have correlation, not diagnosis.
Without copying the final source, create a second small scenario that applies “Hands On Lab and Phase Exit” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Add abuse controls where justified and write security regression tests for discovered cases.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.Rate limiter treated as authentication or authorization
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.