Insecure object reference - Data

Need

Secure access control and data validation

Context

• Requirement of Ruby 2.0 or higher for executing the code
• Usage of Ruby on Rails for building web applications

Description

Non compliant code

class StoresController < ApplicationController
  def show
    @store = Store.find(params[:id])
  end

  def update
    @store = Store.find(params[:id])
    @store.update(store_params)
    redirect_to @store
  end

  private

  def store_params
    params.require(:store).permit(:name, :address)
  end
end

The above code is vulnerable to Insecure Direct Object References (IDOR) because it does not validate if the current user has the necessary permissions to access or modify the requested store.

In the show and update actions, the Store object is fetched directly using the id parameter from the request without any access control checks. This means that if an attacker knows or guesses the id of a store, they can view or modify its details even if they are not authorized to do so.

For example, in the update action, an attacker could potentially send a PUT request with a different id in the URL and modify the name and address of a store they do not own. Similarly, in the show action, an attacker could view the details of any store by simply changing the id in the URL.

Steps

• Implement proper authorization checks to ensure that only authorized users can access and modify store information.
• Use a role-based access control (RBAC) system to define and enforce permissions for accessing and modifying store information.
• Validate the user's permissions before allowing them to access or modify store information.
• Ensure that the store identifier is not exposed or easily guessable to prevent unauthorized access to other stores.
• Consider implementing a multi-tenancy architecture to isolate data and prevent unauthorized access to other stores' data.
• Regularly review and update the authorization logic to account for any changes in user roles or permissions.

Compliant code

class StoresController < ApplicationController
  before_action :set_store, only: [:show, :update]
  before_action :authorize_store, only: [:show, :update]

  def show
  end

  def update
    if @store.update(store_params)
      redirect_to @store
    else
      render :edit
    end
  end

  private

  def set_store
    @store = Store.find(params[:id])
  end

  def authorize_store
    unless current_user.can_access_store?(@store)
      redirect_to root_path, alert: "You are not authorized to access this store."
    end
  end

  def store_params
    params.require(:store).permit(:name, :address)
  end
end

The updated code includes a before_action filter that sets the @store instance variable for the show and update actions. This reduces code duplication and ensures that the @store variable is always set before these actions are executed.

The authorize_store method is another before_action filter that checks if the current user is authorized to access the @store. This is done by calling a hypothetical can_access_store? method on the current_user object. If the user is not authorized, they are redirected to the root path with an alert message. This method should be implemented in the User model and should contain the logic for checking if a user has the necessary permissions to access a store.

The update action has been modified to handle the case where the store fails to update due to validation errors. If the update is successful, the user is redirected to the store, otherwise, the edit view is rendered again.

This code assumes that you have a current_user method (commonly provided by authentication libraries like Devise) and that your User model has a can_access_store? method that takes a store as an argument and returns a boolean indicating whether the user has permission to access the store.

This approach ensures that only authorized users can access and modify store information, which fixes the insecure direct object reference vulnerability.

References

• 307.Insecure object reference - Data