Chapter 66: Content Security Policy (CSP)

Testing with Content-Security-Policy-Report-Only

**Part 14: Security & Best Practices** — Chapter 66: Content Security Policy (CSP)

LEARNING OBJECTIVES ⌵
  • Safely test strict CSP policies in production without breaking existing website functionality.
  • Configure the Content-Security-Policy-Report-Only HTTP response header.
  • Direct violation JSON telemetry to reporting endpoints via report-uri and report-to.
  • Migrate incrementally from report-only observation to full enforcement.
🎬 INTERACTIVE VISUAL PIPELINE Core Architecture Simulation
🌐
1. Input
Directives & Tags
⚙️
2. Parse
Tokenizer & AST
🌳
3. Layout
Box Model & Flow
🎨
4. Render
GPU Paint & Composite
PHASE 1: INPUT & DIRECTIVES
Browser receives declarative markup stream, parsing tag tokens and initializing component state.

📖 The Safe Rollout Pipeline

Phase 1 (Observation):
  Header: Content-Security-Policy-Report-Only: default-src 'self'; report-to /csp-violations
  Effect: Violations are logged to telemetry endpoint; NO user scripts are blocked.

Phase 2 (Triage & Whitelisting):
  Review logs in Sentry/Datadog $\rightarrow$ Fix legitimate scripts by adding nonces.

Phase 3 (Full Enforcement):
  Header: Content-Security-Policy: default-src 'self'; report-to /csp-violations
  Effect: Malicious XSS scripts are blocked in real-time! 🛡️

📌 Key Takeaways

  • Never deploy a new CSP policy directly to enforcement without testing via Content-Security-Policy-Report-Only first.
  • Collect violation reports for 1–2 weeks across peak traffic before switching to active enforcement.
  • --

❓ Knowledge Check

1. Which of the following is correct?

2. Which of the following is correct?