Overview
An instance of Security Misconfiguration in Ruby on Rails occurred with CVE-2006-4111 where Rails versions before 1.1.5 allowed remote attackers to execute Ruby code via a File Upload request that manipulates the LOAD_PATH through an HTTP header. This is a CWE-94 code injection vulnerability: untrusted client input influences Ruby's load path, enabling a crafted request to cause the application to require and execute attacker-supplied code. The vulnerability's impact could be severe, potentially allowing full server compromise with data exposure or service disruption. Rails patched this behavior in version 1.1.5 by ensuring user-supplied LOAD_PATH values are not honored when loading uploaded content, reducing the risk of remote code execution.
Affected Versions
Rails < 1.1.5
Code Fix Example
Ruby on Rails API Security Remediation
Vulnerable and Fixed example (Ruby on Rails)
# Vulnerable pattern (illustrative, not recommended for use in newer Rails versions)
class VulnerableUploadsController < ApplicationController
def create
uploaded = params[:file]
load_path = request.headers['LOAD_PATH']
if load_path && !load_path.empty?
# Untrusted input from client influences the Ruby load path
$LOAD_PATH.unshift(load_path)
end
# Potentially dangerous: may require a file from client-controlled location
require uploaded.original_filename
render plain: 'ok'
end
end
# Fixed pattern: do not allow client-controlled load paths or dynamic requires
class SafeUploadsController < ApplicationController
def create
uploaded = params[:file]
dir = Rails.root.join('tmp', 'uploads')
FileUtils.mkdir_p(dir)
path = dir.join(SecureRandom.uuid + File.extname(uploaded.original_filename))
File.open(path, 'wb') { |f| f.write(uploaded.read) }
# Process securely without dynamic code execution from uploads
content = File.read(path)
# Safe parsing/validation of content should occur here
render plain: 'uploaded'
end
end
# Note: In both cases, ensure required libraries are available (e.g., require 'securerandom', require 'fileutils').