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Business information leak - Source Code

Need​

Protection of sensitive business information in source code

Context​

  • Usage of Python 3 for writing and executing Python code
  • Usage of Django for building web applications

Description​

Non compliant code​

from django.http import HttpResponse
from django.views import View
from .models import Employee, Customer

class EmployeeView(View):
    def get(self, request, *args, **kwargs):
        employee_info = Employee.objects.all()
        return HttpResponse(employee_info)

class CustomerView(View):
    def get(self, request, *args, **kwargs):
        customer_info = Customer.objects.all()
        return HttpResponse(customer_info)

The above code is a Django view that is vulnerable to business information leak.

The EmployeeView and CustomerView classes are Django views that handle HTTP GET requests. When a GET request is made to the endpoint associated with these views, the get method is executed.

In both get methods, the code retrieves all objects from the Employee and Customer models respectively. These models presumably contain sensitive business information such as employee and customer details.

The problem arises when this data is returned as an HTTP response without any checks or filters. This means that anyone who can make a GET request to these endpoints can retrieve all the data in these models.

This is a serious information leakage vulnerability as it exposes sensitive business information to potential attackers. In a real-world scenario, this could lead to serious consequences such as identity theft or other forms of fraud.

The vulnerability could be exploited by any malicious actor who is aware of these endpoints. They could simply make a GET request to these endpoints and receive all the data stored in the Employee and Customer models.

This vulnerability could be mitigated by implementing proper access controls to these endpoints, such as requiring authentication and authorization. Additionally, sensitive data should be properly encrypted and/or redacted when being sent in an HTTP response.

Steps​

  • Implement authentication and authorization checks to ensure only authorized users can access the data.
  • Limit the amount of data returned by the endpoints. Instead of returning all fields of the Employee and Customer models, only return the necessary fields.
  • Use Django's built-in serialization framework to convert complex data types into a format that can be rendered into JSON, XML, or other content types.
  • Implement rate limiting to prevent data scraping.
  • Encrypt sensitive data in the database and decrypt it when it is accessed.
  • Log and monitor access to sensitive data to detect and respond to suspicious activities.

Compliant code​

from django.http import JsonResponse
from django.views import View
from django.contrib.auth.mixins import LoginRequiredMixin
from .models import Employee, Customer
from .serializers import EmployeeSerializer, CustomerSerializer
from rest_framework.throttling import AnonRateThrottle
from django.views.decorators.csrf import csrf_exempt
from django.utils.decorators import method_decorator

class EmployeeView(LoginRequiredMixin, View):
    throttle_classes = [AnonRateThrottle]

    @method_decorator(csrf_exempt)
    def get(self, request, *args, **kwargs):
        employee_info = Employee.objects.values('id', 'name', 'position')  # Only return necessary fields
        serialized_info = EmployeeSerializer(employee_info, many=True)
        return JsonResponse(serialized_info.data, safe=False)

class CustomerView(LoginRequiredMixin, View):
    throttle_classes = [AnonRateThrottle]

    @method_decorator(csrf_exempt)
    def get(self, request, *args, **kwargs):
        customer_info = Customer.objects.values('id', 'name', 'purchase_history')  # Only return necessary fields
        serialized_info = CustomerSerializer(customer_info, many=True)
        return JsonResponse(serialized_info.data, safe=False)

The updated code includes several security measures to prevent business information leak:

  1. Authentication and Authorization: The LoginRequiredMixin ensures that only authenticated users can access the views. Django's authentication system is used to manage user accounts and passwords.

  2. Data Limitation: Instead of returning all fields of the Employee and Customer models, the values() method is used to only return the necessary fields.

  3. Serialization: Django's built-in serialization framework is used to convert the QuerySet objects into a JSON format that can be rendered into the HTTP response. The EmployeeSerializer and CustomerSerializer are custom serializer classes that need to be defined in the serializers.py file.

  4. Rate Limiting: The AnonRateThrottle class is used to limit the rate of requests that anonymous users can make to the views. This helps to prevent data scraping.

  5. Cross-Site Request Forgery (CSRF) Protection: The csrf_exempt decorator is used to exempt the views from the CSRF protection for demonstration purposes. In a production environment, you should always protect your views against CSRF attacks.

  6. Encryption: Although not shown in the code, sensitive data in the Employee and Customer models should be encrypted in the database and decrypted when it is accessed. Django provides several ways to encrypt model fields.

  7. Logging and Monitoring: Although not shown in the code, access to the EmployeeView and CustomerView should be logged and monitored to detect and respond to suspicious activities. Django provides several ways to log and monitor views.

References​

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