CVE-2026-5194 wolfSSL ECDSA证书验证绕过漏洞

#!/usr/bin/env python3 """ Conceptual PoC for CVE-2026-5194 This script demonstrates the logic flaw where a short digest is accepted. In a vulnerable version of wolfSSL, if EdDSA/ML-DSA is enabled, checks for ECDSA digest size might be skipped. """ def verify_ecdsa_vulnerable(data, signature, public_key): # Simulate the vulnerable logic # Vulnerability: Missing check for hash size and OID # Extract digest length from the (potentially malformed) signature digest_len = len(data) # Simulating accepting arbitrary data length as digest print(f"[VULNERABLE] Verifying signature with data length: {digest_len}") # In the vulnerable code, if EdDSA is enabled, it might skip: # if (digest_len < MIN_ECDSA_DIGEST_SIZE) return ERROR; # Accepting the signature regardless of the digest size being too small if signature == "valid_signature_structure": # Simplified check return True return False def verify_ecdsa_secure(data, signature, public_key): # Simulate the secure logic MIN_ECDSA_DIGEST_SIZE = 32 # Example for P-256 digest_len = len(data) print(f"[SECURE] Verifying signature with data length: {digest_len}") if digest_len < MIN_ECDSA_DIGEST_SIZE: print(f"[SECURE] Rejected: Digest size {digest_len} is too small.") return False if signature == "valid_signature_structure": return True return False # Scenario: Attacker provides a short digest (e.g., 16 bytes instead of 32) short_data = "A" * 16 sig = "valid_signature_structure" pubkey = "mock_public_key" print("--- Testing Vulnerable Implementation ---") result_vuln = verify_ecdsa_vulnerable(short_data, sig, pubkey) print(f"Result: {result_vuln}\n") print("--- Testing Secure Implementation ---") result_sec = verify_ecdsa_secure(short_data, sig, pubkey) print(f"Result: {result_sec}")