Some notes about application security for Rails application.

What to think about when your application runs in production, things to keep in mind to prevent data leak.


  • No usage of .html_safe anywhere in the code. The app uses safe view helpers such as safe_join, content_tag, etc. to render html.
  • Use protect_from_forgery with: :exception in ApplicationController.
  • No reference to skip_before_action :verify_authenticity_token or protect_from_forgery except: anywhere.
  • All references to javascript_include_tag include the integrity: true argument (more on SRI). You’ll also need to use crossorigin: 'anonymous' for resources fetched from our CDN.
  • config.force_ssl = true is present in config/application.rb or config/environments/production.rb.
  • The session cookie has both the secure and httpOnly flag (usually provided by force_ssl above)
  • The application is serving the following HTTP headers (verify names and values) secure headers configuration
    • X-Frame-Options: DENY
    • X-Content-Type-Options: nosniff
    • X-Download-Options: noopen
    • X-Permitted-Cross-Domain-Policies: none
    • X-Xss-Protection: 1; mode=block
    • Referrer-Policy: origin-when-cross-origin *
    • Content-Security-Policy: block-all-mixed-content; or Content-Security-Policy: upgrade-insecure-requests;
    • Strict-Transport-Security: max-age=631138519; includeSubdomains (includeSubdomains is optional, max-age should be at least 10 years)
  • Rails log scrubber is configured with sensitive parameter names:
    • config.filter_parameters += [:password]
    • config.filter_parameters += [:access_token]
    • config.filter_parameters += [:secret]
    • Any other sensitive params.
  • config.session_store is configured with redis or mysql (usually in config/initializers/session_store.rb)

If you are curious to learn more about security, I suggest you to read about the OSWAP.