Need

Protection of sensitive information in metadata

Context

• Usage of Dart for building cross-platform mobile, web, and desktop applications
• Usage of Shelf for managing and organizing data in a Node.js application

Description

Non compliant code

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

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

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

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

In the above Dart code, we are using the shelf framework to handle HTTP requests. The _echoRequest function is responsible for handling all incoming requests and returning an ok response with the URL of the request.

The vulnerability arises from the fact that the system is returning the URL of the request directly without any sanitization or checks. If the URL contains sensitive information, such as tokens, session identifiers, or other metadata, this information will be exposed in the response. This is a violation of secure coding principles, which recommend not exposing any sensitive information unnecessarily.

In a real-world scenario, an attacker could potentially use this vulnerability to gain unauthorized access to sensitive data or perform actions on behalf of the user. This could lead to serious breaches of privacy and security.

To mitigate this vulnerability, it's recommended to sanitize all user inputs and outputs, and never expose sensitive information in URLs or responses.

Steps

• Identify the sensitive information that is being exposed through the metadata files.
• Remove or obfuscate the sensitive information from the metadata files.
• Implement access controls to restrict who can access the metadata files.
• Encrypt sensitive data to add an additional layer of security.
• Regularly audit your metadata files to ensure no sensitive information is being exposed.
• Consider using a secure server configuration that does not expose metadata files.

Compliant code

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

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

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

shelf.Response _echoRequest(shelf.Request request) {
  return new shelf.Response.ok('Request handled');
}
        
        

The original code was exposing sensitive information through the metadata files by echoing the request URL in the response. This could potentially expose sensitive information contained in the URL, such as query parameters or other data.

The fixed code removes this vulnerability by simply responding with a generic message ('Request handled') instead of echoing the request URL. This ensures that no sensitive information from the request is exposed in the response.

In addition to this code fix, it's also recommended to implement further security measures such as:

- Removing or obfuscating sensitive information from the metadata files.
- Implementing access controls to restrict who can access the metadata files.
- Encrypting sensitive data to add an additional layer of security.
- Regularly auditing your metadata files to ensure no sensitive information is being exposed.
- Considering using a secure server configuration that does not expose metadata files.

These measures will help to further secure your application and protect sensitive information.

References

• 119. Metadata with sensitive information