JWT in the World of Stateful Session Management

Introduction:

Traditionally, session management with an HTTP-only cookie was the preferred method in authentication. This involved generating a random text, such as cryptographic text, and then sending it to the client, i.e., the browser, via cookies. The advantage of this approach is that there is no manipulation of the text on the client side, as JavaScript is unable to access the cookie through document.cookie. However, the hiccup is that the randomly generated session text needs to be stored somewhere on the server. When the client makes a request, the server compares the random text, i.e., session ID, to ensure it matches the one stored on the server.

Stateful and Stateless:

In the context of authentication and authorization, stateful means that the server keeps track of the user's state, session data, and stores login status or preferences, usually in a session or a database. The server uses the session identifier to retrieve stored session data and recognize the user.

In statelessness, the server does not store any information about the user between requests. There is no reliance on any session data stored on the server.

JWT Authentication:

JWT, in its design, is a stateless form of authentication. In modern web and mobile app development, where the frontend and backend are decoupled, JWT authentication is very common and widely used by most developers. A JWT consists of three parts: a header, a payload, and a signature. Thus, the necessary information for authentication is stored within the JWT itself. Upon a request, the server creates a JWT, signs it with a secret key, and sends it back to the client. The client includes this token in the authorization header for subsequent requests.

Why combine Http Only Cookie with JWT?

On the client side, JWTs are typically stored in local storage. This may lead to the risk of cross-site scripting (XSS) attacks. If not properly secured, sensitive information within the JWT could be exposed to client-side attacks. They are stateless by design, and thus, with no session management on the server, features such as revoking a session or centrally managing user sessions across different devices become a challenge.

Traditional session cookies require the server to maintain session information on the server side, constituting a stateful architecture. By storing JWTs in HTTP-only cookies, the risk of XSS attacks is mitigated. It prevents direct access by client-side scripts, reducing the likelihood of exposing sensitive JWT data.

Scaling and Microservices:

Even though the HTTP-only cookie introduces a form of stateful session management, the JWT itself remains stateless. This means that in each microservice, you can independently verify the JWT without needing to communicate with other services or maintain a shared session state. With the decentralized nature of microservices, this approach scales well as your system grows.

The hybrid approach of balancing stateful and stateless authentication provides a flexible solution for authentication and session management in your applications.

References

• https://owasp.org/www-community/HttpOnly

• https://jwt.io/introduction