I have a Single Page Application which is fully HTML+JS+CSS (using frameworks such as jQuery and AngularJS) and a server side API using ASP.NET WebApi.
The SPA is served in a server similar to a CDN and also packaged using Cordova for use in smartphones.
The server side API has a lot of methods which needs authorization and authentication, hence I have to login and pass an identifier from the client side so the server would know who I am.
The problems I am facing:
Once authenticated, where should I store the access token \ session ID?
currently I have built my own authentication method (not OAuth) which returns a session ID, which the client puts in every subsequent HTTP calls in the Authorization header. However, when a user decides to refresh the page, the header is now gone. Solutions are to either save the session ID in a sessionStorage which might be insecure (OWASP doesn't recommend so, but perhaps X-Frame-Options = SAMEORIGIN would be suffice?) or use a HttpOnly cookie for the session management, which brings me to the next point:
If I am using Cookies it's understood that I need to check for CSRF, but if i'm not? is there any reason to add a CSRF? it's in the same scope for the session ID.
I have my own user system and group management which has a robust access checks. Is there any advantage for me to use OAuth and OpenID if I already have a working authorization filter which checks what I need, and isn't roles-string-based? (i.e. Roles="Administrators" etc., but fully CanChangeResource(x))
I have failed to find similar questions which may answer my problems and would appreciate an informative answer.