Need

Secure session management

Context

Description

import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf_session/shelf_session.dart';

// Create session middleware
var sessionMiddleware = sessionMiddlewareMemory();

var handler = const shelf.Pipeline()
    .addHandler(_handleRequest);...

The above Dart code uses the `shelf` and `shelf_session` packages to create a simple server with session management. The server listens on `localhost` port `8080` and responds to each request with a greeting message that includes the session token. The vulnerability lies in the `_handleRequest` function, where a session token is retrieved from the request but no expiration is set on it. This means that even after a user terminates their session, the token remains valid and can be used to make subsequent requests. This is a serious security issue as it could allow an attacker to reuse old session tokens to impersonate users and perform actions on their behalf.

import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf_session/shelf_session.dart';

// Create session middleware
var sessionMiddleware = sessionMiddlewareMemory();

var handler = const shelf.Pipeline()
    .addHandler(_handleRequest);...

The updated code introduces a mechanism to handle session expiration and refresh the session token periodically. In the `_handleRequest` function, we first retrieve the session from the request context. We then check if the session token is expired using the `isExpired` property of the `Session` object. If the session token is expired, we return a 403 Forbidden response. Next, we refresh the session token using the `refresh` method of the `Session` object. This ensures that the session token is periodically updated while the user is active, which can help prevent session hijacking. Finally, we return a response with a greeting message that includes the session token. This is just for demonstration purposes and in a real-world application, you would typically not include the session token in the response. In the `main` function, we start the server and listen for requests on localhost port 8080. The server uses the `handler` function to handle incoming requests, which includes the session middleware for managing sessions.

References