Need

Secure functionality implementation

Context

• Usage of Ruby 2.0+ for developing Ruby applications
• Usage of Rails framework for building web applications

Description

Non compliant code

        class UsersController < ApplicationController
  def update
    @user = User.find(params[:id])
    @user.update_attributes(params[:user])
    redirect_to @user
  end
end
        
        

The above code is a controller action in a Ruby on Rails application, specifically the update action in the UsersController. This action is responsible for finding a user in the database by their id and updating their attributes.

The vulnerability lies in the line @user.update_attributes(params[:user]). This line is directly taking parameters from the request and using them to update the user's attributes. This means that an attacker could potentially send a request with modified parameters to change any attribute of the user, including those that shouldn't be directly editable by users, such as an admin flag or other sensitive data.

This is a classic example of Mass Assignment vulnerability. In this case, the application is insecure because it’s allowing an attacker to specify the id of the user they want to update, and then pass in any parameters they want to change. This is known as "Insecure Direct Object Reference" (IDOR) and can lead to serious data integrity issues.

Steps

• Validate user input to prevent any malicious data from being processed.
• Implement strong authentication and authorization mechanisms to ensure that only authorized users can access and modify user data.
• Use strong parameterization techniques to whitelist and sanitize user input before updating the user record.
• Implement proper error handling and logging to detect and respond to any unauthorized or malicious activities.
• Regularly update and patch the Ruby on Rails framework and its dependencies to address any known security vulnerabilities.

Compliant code

        class UsersController < ApplicationController
  before_action :set_user, only: [:update]
  before_action :authorize_user, only: [:update]

  def update
    if @user.update(user_params)
      redirect_to @user
    else
      render :edit
    end
  end

  private

  def set_user
    @user = User.find(params[:id])
  end

  def authorize_user
    unless current_user == @user
      redirect_to root_path, alert: "You are not authorized to perform this action."
    end
  end

  def user_params
    params.require(:user).permit(:name, :email, :password, :password_confirmation)
  end
end
        
        

The updated code includes several security improvements:

1. Strong Parameterization: The user_params method is used to whitelist and sanitize user input before updating the user record. This prevents an attacker from injecting malicious data or accessing sensitive user data.

2. Authentication and Authorization: The authorize_user method checks if the current user is the same as the user being updated. If not, the action is not authorized and the user is redirected to the root path. This ensures that only authorized users can update user data.

3. Error Handling: If the user update fails (for example, due to invalid input), the update action will render the edit view again, allowing the user to correct their input.

4. Regular Updates and Patches: Although not shown in the code, it is recommended to regularly update and patch the Ruby on Rails framework and its dependencies to address any known security vulnerabilities.

By implementing these security measures, the system can significantly reduce the risk of an attacker leveraging insecure functionality to negatively impact it.

References

• 014. Insecure functionality