Secure generation of cookies with proper SameSite attribute
# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
before_action :set_cookie
private
def set_cookie
cookies[:user_preferences] = {
value: 'dark_mode=true',
expires: 1.year.from_now
}
end
end
In the above code snippet, a cookie named
user_preferences is being set in the
ApplicationController of a Ruby on Rails application. The
ApplicationController is the parent controller from which all other controllers in the application inherit. This means that the
set_cookie method will be run before every action in the application, ensuring that the
user_preferences cookie is always set.
The
set_cookie method sets the
user_preferences cookie with a value of
'dark_mode=true' and an expiry date of 1 year from now. However, you'll notice that the
SameSite attribute is not being set when the cookie is created.
The
SameSite attribute is an effective countermeasure to cross-site request forgery, cross-site script inclusion, and timing attacks. The attribute can have one of three values:
Strict,
Lax, or
None. If the
SameSite attribute is not set, it defaults to
None, which does not provide any protection against the aforementioned attacks.
This lack of the
SameSite attribute in the cookie settings represents a security vulnerability, as it leaves the application exposed to potential attacks.
# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
before_action :set_cookie
private
def set_cookie
cookies[:user_preferences] = {
value: 'dark_mode=true',
expires: 1.year.from_now,
same_site: :strict, # or :lax
secure: Rails.env.production? # only send cookie over https if in production environment
}
end
end
The updated code now sets the
SameSite attribute for the
user_preferences cookie to
:strict. This means that the cookie will only be sent in a first-party context and not be sent along with requests initiated by third party websites. This can help to mitigate the risk of cross-site request forgery (CSRF) attacks.
The
SameSite attribute can also be set to
:lax, which is a little less strict. In this mode, the cookie will be sent with top-level navigations and will be sent with GET requests initiated by third party websites.
In addition to setting the
SameSite attribute, the
secure attribute is also set for the cookie. This attribute ensures that the cookie is only sent over secure (HTTPS) connections. In the updated code, the
secure attribute is only set if the application is running in the production environment. This is because HTTPS is typically only used in production and not in development or test environments.
After making these changes, it's important to thoroughly test the application to ensure that the changes do not introduce any regressions or compatibility issues.