ECB Mode (ARCH7113)

Key php.security.ecb-mode · Severity error · Category security · CWE CWE-327

ECB mode maps identical plaintext blocks to identical ciphertext, so it leaks plaintext patterns and is never IND-CPA secure.

Incorrect

<?php
$cipher = openssl_encrypt($plaintext, 'aes-256-ecb', $key, OPENSSL_RAW_DATA);

Correct

<?php
$iv = random_bytes(12);
$cipher = openssl_encrypt($plaintext, 'aes-256-gcm', $key, OPENSSL_RAW_DATA, $iv, $tag);

Fix

Replace ECB with an authenticated mode (AES-GCM) that uses a fresh random IV/nonce per encryption.