This gem provides a mitigation against CVE-2015-9284 (Cross-Site Request Forgery on the request phase when using OmniAuth gem with a Ruby on Rails application) by implementing a CSRF token verifier that directly uses ActionController::RequestForgeryProtection code from Rails.

Add this line to your application's Gemfile:

gem "omniauth-rails_csrf_protection"

Then run bundle install to install this gem.

You will then need to verify that all links in your application that would initiate OAuth request phase are being converted to a HTTP POST form that contains authenticity_token value. This might simply be done by changing all link_to to button_to, or use link_to ..., method: :post.

This gem does a few things to your application:

• Disable access to the OAuth request phase using HTTP GET method.
• Insert a Rails CSRF token verifier at the before request phase.

These actions mitigate you from the attack vector described in CVE-2015-9284.

Bug reports and pull requests are welcome on GitHub. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the this project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.