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Comment by fny | Hacker News Reader

Couldn't one circumvent CSP by sending the data to a legitimate analytics service that everyone uses like Google Analytics?

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This is why, when I recently built a credit card form, we didn't include any trackers or third-party code (beyond our vendor's). No dependencies at all—our vendor also has no dependencies in the JS we use to implement the CC form.

That did mean no jQuery, no Google Analytics, no NPM modules and we had to build it as a standalone page outside our React setup, but it's worth it to be able to definitively inspect every line of code and provide a CSP that locks that page down tight to just our subdomain and our vendor's.

That's the same as protecting just the login page with https. What prevents code outside the form page from replacing the link which goes to the form page?

Exactly my thought. I guess that would mean it would need some intimate knowledge of the target site this reducing the scalability of the attack. But then again, thee are some clever people out there who could automate it.

Why not host a validated version of jQuery on your server instead of relying on a CDN?

Thanks for this. I've added a note to the post. "...consider having dedicated, lightweight pages for login and credit card collection that don’t ship any third party code (npm packages, advertising, analytics, GTM, etc.)"

Here's hoping you do the same for your login form! :D

Incredible

very interesting!

How would you exfiltrate that data?

Google Analytics has a query parameter that can be used to extract arbitrary data. So make a request to that with an ID that you control I guess? GitHub mentions it in their CSP post: https://githubengineering.com/githubs-post-csp-journey/

Related: this Analytics attack has actually happened

https://www.reddit.com/r/btc/comments/7dsmvd/my_analysis_of_...

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