Description

This vulnerability detector identifies hardcoded AEAD (Authenticated Encryption with Associated Data) nonces in Rust code that uses OpenSSL. Using hardcoded nonces in AEAD encryption is a critical security flaw that completely breaks the security guarantees of the encryption scheme, making encrypted data vulnerable to various attacks including plaintext recovery.

Detection Strategy

• Scans Rust source code files that import the OpenSSL crate

• Identifies function calls to AEAD encryption methods (such as encrypt, decrypt, or cipher operations)

• Examines the cipher argument to verify it's configured for AEAD mode encryption

• Checks the IV (Initialization Vector) or nonce argument to determine if it contains hardcoded values

• Reports a vulnerability when both conditions are met: the cipher is in AEAD mode and the nonce/IV parameter uses a hardcoded value instead of a randomly generated one

Vulnerable code example

use openssl::symm::{encrypt_aead, Cipher};

fn encrypt_data(key: &[u8], plaintext: &[u8], aad: &[u8], tag: &mut [u8]) -> Vec<u8> {
    // VULNERABLE: hardcoded nonce reused on every encryption
    encrypt_aead(Cipher::aes_256_gcm(), key, Some(b"000000000000"), aad, plaintext, tag).unwrap()
}

fn encrypt_with_variable(key: &[u8], plaintext: &[u8], aad: &[u8], tag: &mut [u8]) -> Vec<u8> {...

✅ Secure code example

use openssl::symm::{encrypt_aead, Cipher};
use rand::{rngs::OsRng, RngCore};

fn encrypt_data(key: &[u8], plaintext: &[u8], aad: &[u8], tag: &mut [u8]) -> Vec<u8> {
    let mut nonce = [0u8; 12];
    OsRng.fill_bytes(&mut nonce);
    // SAFE: nonce is randomly generated for each encryption call
    encrypt_aead(Cipher::aes_256_gcm(), key, Some(&nonce), aad, plaintext, tag).unwrap()...