Description

This vulnerability detector identifies the use of legacy RSA PKCS#1 v1.5 padding scheme in Python cryptographic operations. PKCS#1 v1.5 padding is vulnerable to padding oracle attacks and has been deprecated in favor of more secure padding schemes like OAEP (Optimal Asymmetric Encryption Padding).

Detection Strategy

• Reports when code uses PyCryptodome's Crypto.Cipher.PKCS1_v1_5.new() method for RSA encryption/decryption

• Reports when code uses cryptography library's PKCS1v15 padding with encrypt() or decrypt() operations

• Triggers specifically when importing and using either PyCryptodome's legacy PKCS1_v1_5 cipher or when passing PKCS1v15 padding as an argument to RSA encryption/decryption functions

Vulnerable code example

from cryptography.hazmat.primitives.asymmetric import padding
from Crypto.Cipher import PKCS1_v1_5

def encrypt_data(public_key, data):
    # VULNERABLE: Uses legacy PKCS#1 v1.5 padding scheme
    return public_key.encrypt(data, padding.PKCS1v15())

def decrypt_data(private_key, ciphertext):...

✅ Secure code example

from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import hashes
from Crypto.Cipher import PKCS1_OAEP

def encrypt_data(public_key, data):
    # SECURE: Uses OAEP padding instead of vulnerable PKCS#1 v1.5
    return public_key.encrypt(
        data,...