Comment by chrisfosterelli
6 years ago
That's correct, and part of my point. If they used CORS headers correctly it could both be secure and not require a crazy image hack.
The image hack seems like a lot of work to go through to make an app LESS secure.
I'm a bit confused, so CORS doesn't apply when trying to load an image?
If they set CORS to allow interaction from anywhere, why use an image and not load data with js?
CORS is set up to protect data from being given to a third party, e.g. JS requests obtaining and being able to observe data they shouldn't have access to. Since images are being loaded by the browser (second party), there is no such protection, since a third party should not be able to read them anyway (barring some other vulnerability). It's assumed the first party is correctly doing what it's supposed to, an example could be fetching an image from a cdn.
Hmm I still don't understand why they have to use the image hack. Since they control the server on localhost they can set the CORS headers to allow all domains, then JS from a site could access localhost right?
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