CODEWITHSUNDEEP
ruby-on-railssecurityauthorization
volk
volk

Reputation: 1196

Rails security concerns with Authorization token in header for API

I'm building an API and I want every request to contain a token. I found a pretty simple way to do this, but I am wondering if I'm missing any security implications.

The way I'm currently doing it is using authenticate_or_request_with_http_token. I use that to check the token within the header combined with the user's email within a request. If both are legitimate -- then go through with the request.

I am also enforcing https on every request. Is this enough for a secure app? If somebody intercepts the request they can just take the params and the headers and make requests on behalf of a user, but I figured that ssl should encode everything properly. Am I completely misunderstanding ssl as well as the rest of the way I built it?

Upvotes: 1

Views: 591

Answers (1)

jrochkind
jrochkind

Reputation: 23357

I think you are basically right.

But the most secure way to do API auth is with something like hmac, where the token is actually generated specific to the specific request and the time, so even if someone does see the URL, they still can't even use it to replay the same API request, let alone make other requests.

http://rc3.org/2011/12/02/using-hmac-to-authenticate-web-service-requests/

For instance, Amazon uses an HMAC-based approach to their API's.

But I think your analysis is correct that in general, if you enforce https, nobody ought to be able to see the pass token clients include in the request. I can't explain why people use HMAC instead; maybe just because there are so so many things that can go wrong and lead to someone seeing the token even in request headers. Including several kinds of man-in-the-middle attacks which ought not to be possible, but if a slip-up somewhere else makes one possible, the HMAC-based approach will still, for instance, prevent a man-in-the-middle from modifying the request the client meant to send, before it reaches the server.

There is HMAC built into the ruby stdlib. Digest::HMAC in the stdlib tells you to use OpenSSL::HMAC instead, but OpenSSL::HMAC contains no docs at all, and Digest::HMAC at least includes some bare bones examples docs. It would be nice to have better docs, but together with the overview of HMAC linked above, you can probably figure out how to use the stdlib ruby hmac to implement your auth pretty easily. It does put a higher burden on the client though, to find an HMAC library in the language of their choice, and implement the hmac auth to your app's specifications (there are a couple choices in how you might incorporate hmac into actual auth flow).

Upvotes: 2

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