Throughout my 5-year career in frontend development, almost every application I built utilized JWT Tokens. Typically, these tokens were stored in the browser’s storage, such as localStorage or sessionStorage. Initially, I felt comfortable with this method due to its simplicity and convenience, and many articles also used localStorage or sessionStorage as the standard example.
However, as I gained a deeper understanding of hacker tactics, I began to question the security of using localStorage, especially for sensitive data. This led me to explore HttpOnly Cookies, which turned out to be the best solution for securely storing JWT Tokens.
HTTPOnly cookies are cookies that have the HTTPOnly attribute, which prevents client-side scripts from accessing the data stored in the cookie.
Why should we implement HttpOnly Cookies?
1. Protection against XSS (Cross-Site Scripting):
HttpOnly Cookies cannot be accessed via JavaScript, providing better security against XSS attacks.
2. Automatic management by the browser: Cookies are automatically sent with every HTTP request to the appropriate domain, reducing implementation complexity.
3. Effortless for frontend developers: Frontend developers no longer need to manage JWT Tokens or store them in the browser’s storage, reducing the client-side security management burden.
4. Security attribute settings: Attributes such as Secure, SameSite, and HttpOnly strengthen data protection by restricting how data can be accessed and transmitted.
- Client -> Server: Login Request The client sends a login request containing the username and password to the server.
- Server -> AuthService: Validate credentials The server forwards the credentials (username and password) to the authentication service for validation.
- AuthService -> DB: Query user by username The authentication service queries the database to retrieve the user record based on the provided username.
- DB → AuthService: Return user record The database returns the user record (e.g., hashed password, role, etc.).
- AuthService -> Server: Return user authentication status The authentication service returns the authentication status to the server (valid or invalid).
- Server -> JWTValidator: Generate JWT If the credentials are valid, the server requests the JWT Validator to generate a JWT based on the user’s data.
- JWTValidator → Server: Return JWT The JWT Validator generates and returns the JWT to the server.
- Server -> Client: Set HttpOnly Cookie with JWT The server sends the JWT to the client as an HttpOnly cookie, which is stored in the browser.
- Client -> Server: Authenticated Request The client sends an authenticated request to the server, automatically including the HttpOnly cookie with the JWT.
- Server -> JWTValidator: Validate JWT from Cookie The server sends the JWT from the cookie to the JWT Validator for validation.
- JWTValidator → Server: Return JWT validation status The JWT Validator checks the token’s validity. If valid, the request is processed; otherwise, a 401 Unauthorized response is sent to the client.
- alt Valid JWT If the JWT is valid, the server processes the request (e.g., fetching data or resource) and returns the response to the client.
- else Invalid JWT If the JWT is invalid, the server responds with a 401 Unauthorized status.
Conclusions
By implementing HttpOnly Cookies, we can enhance the security of our website and protect users from potential attacks, particularly those related to XSS. I hope this article provides valuable insights. If you have any suggestions or more practical approaches, feel free to discuss them with me. Keep learning and stay curious!
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