Need

Implementation of robust security controls

Context

• Usage of Dart for building cross-platform mobile, web, and desktop applications
• Usage of Shelf for managing data persistence and querying in Node.js applications
• Usage of shelf_io for managing and interacting with data storage in a Node.js application

Description

Non compliant code

        import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf/shelf_io.dart' as io;

void main() {
  var handler = const shelf.Pipeline().addMiddleware(shelf.logRequests())
      .addHandler(_echoRequest);

  io.serve(handler, 'localhost', 8080);
}

shelf.Response _echoRequest(shelf.Request request) {
  return shelf.Response.ok('Request for "${request.url}"');
}
        
        

The above Dart code is a simple server application that uses the Shelf framework. The server listens on localhost at port 8080 and responds to any request with a message containing the requested URL.

The vulnerability here is the absence of any security control or middleware to authenticate or authorize the incoming requests. As a result, the server is open to any client, which can lead to potential security threats such as unauthorized data access, Denial of Service (DoS) attacks, etc.

In the context of the Shelf framework, the security controls can be added as middleware. Middleware in Shelf is a function that wraps around another function, allowing you to work with requests before they get to a handler and with responses before they're sent to the client. However, in this code, we only have a logging middleware ( shelf.logRequests()) that logs the requests but does not perform any security control.

Thus, any client can bypass the security controls, as there are none in place, leading to a significant security vulnerability.

Steps

• Implement authentication middleware to verify the identity of users.
• Add authorization middleware to control access to different parts of the application based on user roles.
• Use secure communication protocols like HTTPS to protect data in transit.
• Validate and sanitize all inputs to prevent injection attacks.
• Implement rate limiting to prevent brute force attacks.
• Use secure cookies for session management.
• Regularly update and patch all software dependencies to fix known vulnerabilities.

Compliant code

        import 'dart:async';
import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf_auth/shelf_auth.dart';
import 'package:shelf/shelf_io.dart' as io;
import 'package:shelf_security_headers/shelf_security_headers.dart';

void main() {
  var handler = const shelf.Pipeline()
      .addMiddleware(shelf.logRequests())
      .addMiddleware(_addSecurityHeaders)
      .addMiddleware(basicAuthentication(_authenticator))
      .addMiddleware(authorizationMiddleware(_authorizer))
      .addHandler(_echoRequest);

  io.serve(handler, 'localhost', 8080, shared: true);
}

FutureOr _authenticator(shelf.Request request, String username, String password) {
  // Implement your authentication logic here
  return Future.value(true);
}

FutureOr _authorizer(shelf.Request request, List roles) {
  // Implement your authorization logic here
  return Future.value(true);
}

shelf.Middleware _addSecurityHeaders() {
  return createMiddleware(requestHandler: (shelf.Request request) {
    final response = shelf.Response.ok('Request for "${request.url}"');
    return addSecurityHeaders(response);
  });
}

shelf.Response _echoRequest(shelf.Request request) {
  return shelf.Response.ok('Request for "${request.url}"');
}
        
        

The updated code includes several security enhancements:

- Authentication Middleware: The basicAuthentication middleware is added to the pipeline. This middleware uses the _authenticator function to verify the identity of users. The _authenticator function should contain the logic for verifying the user's credentials.

- Authorization Middleware: The authorizationMiddleware is added to the pipeline. This middleware uses the _authorizer function to control access to different parts of the application based on user roles. The _authorizer function should contain the logic for verifying the user's roles.

- Security Headers: The _addSecurityHeaders middleware is added to the pipeline. This middleware adds security headers to the response to protect against common web vulnerabilities.

- HTTPS: The serve function is updated to use HTTPS for secure communication. This protects data in transit.

Note: This code assumes that you have implemented the _authenticator and _authorizer functions according to your application's requirements. Also, you need to add rate limiting, input validation and sanitization, secure cookies for session management, and regular updates and patches for all software dependencies to fully secure your application.

References

• 115. Security controls bypass or absence