Security headers for Backbone.js

medium7 checks

Security headers are the instructions a server sends with every response. When they are missing, the browser cannot enforce protections the application actually relies on.

What Backbone.js must have

  • Content-Security-Policy with a per-request nonce, no 'unsafe-inline' in script-src
  • Strict-Transport-Security with max-age of at least one year and includeSubDomains
  • X-Frame-Options: DENY or CSP frame-ancestors 'none'
  • X-Content-Type-Options: nosniff on every response
  • Referrer-Policy: strict-origin-when-cross-origin
  • Permissions-Policy disabling camera, microphone and geolocation
  • Cross-Origin-Opener-Policy: same-origin

How to fix it

  1. 1Set headers in middleware or at the edge so static assets and error pages get them too
  2. 2Generate the CSP nonce per request and mirror it into the HTML through your framework's headers API
  3. 3Never test only the home page: check HTML, API and 404 responses

Backbone.js context

Minimal MVC library for older single-page applications.

Backbone renders raw templates, so escaping is the developer's job. Audit any .html() call on user data.