Improper control of interaction frequency - Ruby

Need

Enforce proper control of interaction frequency to prevent abuse and ensure fair resource allocation

Context

1. Usage of Ruby 2.7.4 for Ruby programming and development
2. Usage of Rails framework for building web applications
3. Usage of ActiveRecord for Object-Relational Mapping (ORM) in database operations

Description

Insecure Code Example

class PostsController < ApplicationController
  def create
    post = Post.new(post_params)
    if post.save
      render json: post, status: :created
    else
      render json: post.errors, status: :unprocessable_entity
    end
  end

  private

  def post_params
    params.require(:post).permit(:title, :content)
  end
end

In the above code, we have a `PostsController` with a `create` action that is used to create new posts. The `create` action creates a new `Post` object with parameters `title` and `content` that are passed in the request. If the post is saved successfully, it returns the post as JSON with a status code of `201 (created)`. If it fails, it returns the errors as JSON with a status code of `422 (unprocessable entity)`. The vulnerability in this code is that there is no control over the frequency of interactions. This means that a user can send as many requests to this endpoint as they want in a short period of time. This can lead to a Denial of Service (DoS) attack where the server gets overwhelmed with too many requests and can't process legitimate requests. This can also lead to a user creating a large number of posts in a short period of time, which can be a form of spamming.

Steps

1. Implement rate limiting to restrict the number of requests a user can make within a specific time frame.
2. Use a middleware or a gem that provides rate limiting functionality.
3. Configure the rate limit settings such as the maximum number of requests allowed per user and the time frame for the limit.
4. Handle the rate limit exceeded scenario by returning an appropriate response, such as a 429 Too Many Requests status code.
5. Consider implementing additional security measures like IP-based rate limiting or using a distributed rate limiting solution for scalability.
6. Test the rate limiting functionality to ensure it is working as expected.

Secure Code Example

# Add the rack-attack gem to your Gemfile
gem 'rack-attack'

# Then run bundle install
bundle install

# Create a new file config/initializers/rack_attack.rb and add the following code:

class Rack::Attack
  Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new 

  throttle('req/ip', limit: 5, period: 5) do |req|
    req.ip
  end
end

# Update the application.rb file to use the Rack::Attack middleware:

class Application < Rails::Application
  config.middleware.use Rack::Attack
end

# Update the PostsController to handle the rate limit exceeded scenario:

class PostsController < ApplicationController
  def create
    post = Post.new(post_params)
    if post.save
      render json: post, status: :created
    else
      render json: post.errors, status: :unprocessable_entity
    end
  rescue Rack::Attack::Request::Throttled
    render json: { error: 'Rate limit exceeded' }, status: 429
  end

  private

  def post_params
    params.require(:post).permit(:title, :content)
  end
end

The above code fixes the vulnerability by implementing rate limiting using the `rack-attack` gem. First, we add the `rack-attack` gem to the Gemfile and run `bundle install` to install it. Next, we create a new initializer file `rack_attack.rb` and configure the rate limit settings. In this case, we limit the number of requests to 5 per 5 seconds per IP address. Then, we update the `application.rb` file to use the `Rack::Attack` middleware. Finally, we update the `PostsController` to handle the rate limit exceeded scenario. If a user exceeds the rate limit, the server will respond with a 429 Too Many Requests status code and a JSON message indicating that the rate limit has been exceeded. This solution effectively prevents a user from making too many requests to the server in a short period of time, thus mitigating the risk of a denial-of-service attack.

References

Last updated

2023/09/18