Curtis Brazzell

Jul 18, 2020

6 min read

Proxying Exfil Data Through Images

Intro

On the heels of my last blog when I discovered how to prevent all of my phishing emails from landing on any blacklists, I realized that sometimes Gmail, Microsoft 365, and possibly other email providers will mark an email as suspicious simply because an embedded tracking pixel doesn’t really reference an image at all. What if there was a way to reference a real image but also pass parameters through to a back-end? What if you could use trusted third party image hosting services at places like Google and Imgur to relay information across? Aside from phishing, maybe…