Security Headers Configuration

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• Best Practices

Overview

Implement comprehensive HTTP security headers to protect web applications from XSS, clickjacking, MIME sniffing, and other browser-based attacks.

When to Use

• New web application deployment
• Security audit remediation
• Compliance requirements
• Browser security hardening
• API security
• Static site protection

Quick Start

Minimal working example:

// security-headers.js
const helmet = require("helmet");

function configureSecurityHeaders(app) {
  // Comprehensive Helmet configuration
  app.use(
    helmet({
      // Content Security Policy
      contentSecurityPolicy: {
        directives: {
          defaultSrc: ["'self'"],
          scriptSrc: [
            "'self'",
            "'unsafe-inline'", // Remove in production
            "https://cdn.example.com",
            "https://www.google-analytics.com",
          ],
          styleSrc: [
            "'self'",
            "'unsafe-inline'",
            "https://fonts.googleapis.com",
          ],
          fontSrc: ["'self'", "https://fonts.gstatic.com"],
          imgSrc: ["'self'", "data:", "https:", "blob:"],
          connectSrc: ["'self'", "https://api.example.com"],
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide	Contents
Node.js/Express Security Headers	Node.js/Express Security Headers
Nginx Security Headers Configuration	Nginx Security Headers Configuration
Python Flask Security Headers	Python Flask Security Headers
Apache .htaccess Configuration	Apache .htaccess Configuration
Security Headers Testing Script	Security Headers Testing Script

Best Practices

✅ DO

• Use HTTPS everywhere
• Implement strict CSP
• Enable HSTS with preload
• Block framing with X-Frame-Options
• Prevent MIME sniffing
• Report CSP violations
• Test headers regularly
• Use security scanners

❌ DON'T

• Allow unsafe-inline in CSP
• Skip HSTS on subdomains
• Ignore CSP violations
• Use overly permissive policies
• Forget to test changes