On ColdFusion, AES, and Padding Oracle Attacks: Hic Sunt Dracones

TL; DR: If you use AES-CBC (or another block cipher operating in CBC mode) to decrypt user-controlled ciphertext, validate the ciphertext with an HMAC or similar integrity check prior to decryption to avoid Padding Oracle vulnerabilities.  All user-controlled input is untrusted and can be dangerous, even if it is encrypted data.

Why You Don't Want To Use CFMX_COMPAT Encryption

This is the first of what may be a couple of posts about my presentation from ColdFusion Summit East 2023, which was held in April in Washington, DC.

Let's talk about ColdFusion and encryption.  Specifically -- about the CFMX_COMPAT algorithm.  The encrypt() function was introduction in ColdFusion 4 (ca. November 1998), and CFMX_COMPAT was the only algorithm available.  The release of ColdFusion 7 (ca. February 2005) added native support for AES, 3DES, DES, and Blowfish.  But CFMX_COMPAT remains the default algorithm used by the encrypt() function.   

Slides from ColdFusion Summit East 2023 - "Codes, Ciphers, and ColdFusion: What They Don't Want You To Know"

I spoke at ColdFusion Summit East 2023 last week.  I was fortunate to catch some good talks and Springtime in Washington, DC is always a great time to visit.  My talk was on ColdFusion and Encryption -- what to use, what not to use, and how to securely implement encryption into your applications.  I've shared my slides below, and I plan to turn the content into a few forthcoming blog posts.