Description

Detects when cryptographic initialization vectors (IV) or nonces are derived from encryption keys in PHP applications. This vulnerability weakens encryption security because predictable or key-derived IVs can allow attackers to recover plaintext or detect patterns in encrypted data, violating cryptographic best practices that require random, unique IVs.

Detection Strategy

• Scans PHP source code for cryptographic function calls from OpenSSL or PHPSecLib libraries

• Identifies function calls where initialization vectors or nonces appear to be derived from the same cryptographic key being used for encryption

• Triggers when the analysis detects that IV/nonce generation depends on or derives from the encryption key rather than using secure random generation

• Reports vulnerabilities in both native OpenSSL functions and third-party PHPSecLib cryptographic operations that exhibit this insecure pattern

Vulnerable code example

<?php
use phpseclib3\Crypt\AES;

function encryptWithSameKeyAsIV($data) {
    $key = random_bytes(16);
    // VULNERABLE: IV reuses the same bytes as the encryption key
    return openssl_encrypt($data, 'aes-128-cbc', $key, OPENSSL_RAW_DATA, $key);
}...

✅ Secure code example

<?php
use phpseclib3\Crypt\AES;

function encryptWithSameKeyAsIV($data) {
    $key = random_bytes(16);
    // SAFE: Generate random IV instead of reusing key
    $iv = random_bytes(16);
    return openssl_encrypt($data, 'aes-128-cbc', $key, OPENSSL_RAW_DATA, $iv);...