Nginx - Security Headers and SSL Hardening

# In /etc/nginx/conf.d/security-headers.conf

# Prevents clickjacking (embedding in iframe)
add_header X-Frame-Options "SAMEORIGIN" always;

# Prevents MIME type sniffing
add_header X-Content-Type-Options "nosniff" always;

# Enables browser's XSS filter (legacy, but useful)
add_header X-XSS-Protection "1; mode=block" always;

# Referrer Policy: limits info sent to external sites
add_header Referrer-Policy "strict-origin-when-cross-origin" always;

# Browser API Permissions (limit camera, microphone, etc.)
add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;

# HSTS: force HTTPS for 1 year (only after verifying HTTPS works!)
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

add_header Content-Security-Policy "
  default-src 'self';
  script-src 'self';
  style-src 'self' 'unsafe-inline';
  img-src 'self' data: https:;
  font-src 'self';
  connect-src 'self';
  frame-ancestors 'none';
" always;

add_header Content-Security-Policy "
  default-src 'self';
  script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdnjs.cloudflare.com https://www.googletagmanager.com;
  style-src 'self' 'unsafe-inline' https://fonts.googleapis.com;
  img-src 'self' data: https:;
  font-src 'self' https://fonts.gstatic.com;
  connect-src 'self' https://www.google-analytics.com;
  frame-src 'self' https://www.youtube.com;
" always;

sudo nano /etc/nginx/conf.d/ssl-hardening.conf

# Protocols: only TLS 1.2 and 1.3
ssl_protocols TLSv1.2 TLSv1.3;

# Secure cipher suite (Mozilla Modern)
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
ssl_prefer_server_ciphers off;

# Session cache (improves SSL performance)
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 1d;
ssl_session_tickets off;

# OCSP Stapling (faster certificate revocation check)
ssl_stapling on;
ssl_stapling_verify on;
resolver 1.1.1.1 8.8.8.8 valid=300s;
resolver_timeout 5s;

# DH params (additional security)
# Generate with: sudo openssl dhparam -out /etc/ssl/dhparam.pem 2048
ssl_dhparam /etc/ssl/dhparam.pem;

server {
    listen 80;
    server_name mysite.com www.mysite.com;
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl http2;
    server_name mysite.com www.mysite.com;

    ssl_certificate /etc/letsencrypt/live/mysite.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/mysite.com/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

    # Security headers
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;

    # Hide Nginx version
    server_tokens off;

    # Limit HTTP methods
    if ($request_method !~ ^(GET|POST|HEAD|PUT|DELETE|PATCH)$) {
        return 405;
    }

    root /var/www/mysite.com;
    index index.html index.php;

    location / {
        try_files $uri $uri/ =404;
    }
}

# nginx.conf → http {}
server_tokens off;

# /etc/php/8.x/fpm/php.ini
expose_php = Off

# nginx.conf → http {}
limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;

# In server {} or location {}
location /wp-login.php {
    limit_req zone=login burst=3 nodelay;
    try_files $uri $uri/ =404;
}

location /api/login {
    limit_req zone=login burst=5 nodelay;
    proxy_pass http://localhost:3000;
}