Be careful when going client-only (Firebase)

Completely agree with the implications in this article. My experience in building a Firebase app was that it was easy to design the app's first cut, as long as security / privacy was not taken care of.

As soon as security / privacy / quota needs to be factored in, the whole model collapses. Security requires a lot of careful and complex design in the FireBase system. And it wasn't even possible to implement quotas the last I checked (couple of months back).

Nice DWM setup :)

This was something that really prevented me from pursuing Firebase as a real asset, despite its easy real time socket magic. If there's a diagram to "roll your own" after, though, it's probably moot (forums/ chat). Their json-rpc server has a really slick api and they've spent a lot of time on problems such as authentication and data security.

You could argue that moot is just a very well designed Firebase app as far as security permissions go, but at least it's proof that it's possible to rely entirely on pub/sub for your app and be fast, scalable, and successful.

Basically by disallowing read access to /users in the Firebase security rules (which you should do), the latter 50% of the article would be moot. However the html injection is interesting, be extra careful to validate data when using dynamic jquery-selectors?

[Firebase Founder] Hi Robin,

You’re right, some folks don’t fully setup their security rules. We remind our developers to do this, but can -- and clearly need -- to do more. Your suggestion about requiring security rules is a good one. We’ll be going through our customers and providing more personalized feedback on their security rules in the coming days. Also, we are working on additional tutorials and examples to teach our devs how to use our security rules in an interactive way.

Thanks for pointing out some of the areas we can improve our examples. They’re intended to illustrate design patterns, not be robust production apps. Again, we can do better here, and the code we use as an example should be bullet proof.

Like any application, Firebase-powered apps are only as secure as the developers make them. If you do not control access with security rules, your app could be vulnerable. XSS attacks can affect Firebase apps like any other application.

Finally, we would have really liked you to provide responsible disclosure on the specific Firebases you found issue with and given us enough time to speak with those customers before taking this public.

We’ll reach out to you via email now.