I am using Ruby on Rails 4.1.1 and I am thinking to accept parameters (through URL query strings) that are passed directly to the
# URL in the browser
redirect_to url_for(params[:redirect_to].merge(:only_path => true))
This it is safe internally as Ruby On Rails will only be issuing a HTTP redirect response.
As you are using
only_path this will protect you from an Open redirect vulnerability. This is where an email is sent by an attacker containing a link in the following format (say your site is
As the user checks the URL and sees it is on the
example.com domain they beleive it is safe so click the link. However, if there's an open redirect then the user ends up on
evil.com which could ask for their
example.com password without the user noticing.
Redirecting to a relative path only on your site fixes any vulnerability.
In your case you are giving users control of your controller, action and parameters. As long as your GET methods are safe (i.e. no side-effects), an attacker could not use this by creating a crafted link that the user opens.
In summary, from the information provided I don't see any risk from phishing URLs to your application.