class Railroader::CheckYAMLParsing

Public Instance Methods

disabled_xml_dangerous_types?() click to toggle source
# File lib/railroader/checks/check_yaml_parsing.rb, line 97
def disabled_xml_dangerous_types?
  if version_between? "0.0.0", "2.3.14"
    matches = tracker.check_initializers(:"ActiveSupport::CoreExtensions::Hash::Conversions::XML_PARSING", :delete)
  else
    matches = tracker.check_initializers(:"ActiveSupport::XmlMini::PARSING", :delete)
  end

  symbols_off = false
  yaml_off = false

  matches.each do |result|
    arg = result.call.first_arg

    if string? arg
      if arg.value == "yaml"
        yaml_off = true
      elsif arg.value == "symbol"
        symbols_off = true
      end
    end
  end

  symbols_off and yaml_off
end
disabled_xml_parser?() click to toggle source
# File lib/railroader/checks/check_yaml_parsing.rb, line 48
def disabled_xml_parser?
  if version_between? "0.0.0", "2.3.14"
    # Look for ActionController::Base.param_parsers.delete(Mime::XML)
    params_parser = s(:call,
                      s(:colon2, s(:const, :ActionController), :Base),
                      :param_parsers)

    matches = tracker.check_initializers(params_parser, :delete)
  else
    # Look for ActionDispatch::ParamsParser::DEFAULT_PARSERS.delete(Mime::XML)
    matches = tracker.check_initializers(:"ActionDispatch::ParamsParser::DEFAULT_PARSERS", :delete)
  end

  unless matches.empty?
    mime_xml = s(:colon2, s(:const, :Mime), :XML)

    matches.each do |result|
      if result.call.first_arg == mime_xml
        return true
      end
    end
  end

  false
end
enabled_yaml_parser?() click to toggle source

Look for ActionController::Base.param_parsers = :yaml in Rails 2.x apps

# File lib/railroader/checks/check_yaml_parsing.rb, line 76
def enabled_yaml_parser?
  param_parsers = s(:call,
                    s(:colon2, s(:const, :ActionController), :Base),
                    :param_parsers)

  matches = tracker.check_initializers(param_parsers, :[]=)

  mime_yaml = s(:colon2, s(:const, :Mime), :YAML)

  matches.each do |result|
    if result.call.first_arg == mime_yaml and
      symbol? result.call.second_arg and
      result.call.second_arg.value == :yaml

      return true
    end
  end

  false
end
run_check() click to toggle source
# File lib/railroader/checks/check_yaml_parsing.rb, line 8
def run_check
  return unless version_between? "0.0.0", "2.3.14" or
                version_between? "3.0.0", "3.0.18" or
                version_between? "3.1.0", "3.1.9" or
                version_between? "3.2.0", "3.2.10"

  unless disabled_xml_parser? or disabled_xml_dangerous_types?
    new_version = if version_between? "0.0.0", "2.3.14"
                    "2.3.15"
                  elsif version_between? "3.0.0", "3.0.18"
                    "3.0.19"
                  elsif version_between? "3.1.0", "3.1.9"
                    "3.1.10"
                  elsif version_between? "3.2.0", "3.2.10"
                    "3.2.11"
                  end

    message = "Rails #{rails_version} has a remote code execution vulnerability: upgrade to #{new_version} or disable XML parsing"

    warn :warning_type => "Remote Code Execution",
      :warning_code => :CVE_2013_0156,
      :message => message,
      :confidence => :high,
      :gem_info => gemfile_or_environment,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/61bkgvnSGTQ/discussion"
  end

  # Warn if app accepts YAML
  if version_between?("0.0.0", "2.3.14") and enabled_yaml_parser?
    message = "Parsing YAML request parameters enables remote code execution: disable YAML parser"

    warn :warning_type => "Remote Code Execution",
      :warning_code => :CVE_2013_0156,
      :message => message,
      :confidence => :high,
      :gem_info => gemfile_or_environment,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/61bkgvnSGTQ/discussion"
  end
end