Overview
CVE-2006-4112 describes an Unrestricted Resource Consumption vulnerability in early Ruby on Rails (Rails 1.1.0 through 1.1.5) where the framework's dependency resolution mechanism within the routing code could be misused. An attacker could craft a URL that causes the routing/dependency resolution to misbehave, potentially enabling remote execution of Ruby code, leading to denial of service (application hang) or data loss. This was a real-world risk tied specifically to the dependency resolution path rather than ordinary requests, and it highlighted how dynamic routing logic can be exploited when user input is not properly constrained. The vulnerability is explicit about the risk stemming from the routing code handling of URL components and how that can be manipulated to cause unintended behavior at runtime.
Affected Versions
Rails 1.1.0 through 1.1.5
Code Fix Example
Ruby on Rails API Security Remediation
Vulnerable pattern (unsafe):
# config/routes.rb
# Warning: this catch-all routing allows dynamic dispatch from user input
match ':controller/:action/:id', via: :get
# app/controllers/vulnerable_controller.rb
class VulnerableController < ApplicationController
def route
c = params[:controller]
a = params[:action]
# UNSAFE: uses user-controlled strings to dispatch
Object.const_get(c).new.send(a)
end
end
Fixed pattern (safe):
# config/routes.rb
Rails.application.routes.draw do
# Explicit, whitelisted routes only
get 'home/index', to: 'home#index'
get 'products/:id', to: 'products#show'
end
# app/controllers/home_controller.rb
class HomeController < ApplicationController
def index; end
end
# app/controllers/whitelist_dispatch_controller.rb
class WhitelistDispatchController < ApplicationController
def route
case params[:controller_name]
when 'Home'
HomeController.action(params[:action_name]).call(request.env) if %w[index show].include?(params[:action_name])
when 'Products'
ProductsController.action(params[:action_name]).call(request.env) if %w[show index].include?(params[:action_name])
else
head :forbidden
end
end
end