Skip to main content

Authentication mechanism absence or evasion

Need​

Implementation of a robust and secure authentication mechanism

Context​

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

Description​

Non compliant code​

from django.http import HttpResponse
from django.views import View

class SecretView(View):
    def get(self, request):
        return HttpResponse('This is a secret view')

# In urls.py
from django.urls import path
from .views import SecretView

urlpatterns = [
    path('secret/', SecretView.as_view(), name='secret'),
]

In the above Python code using Django framework, we have a view named SecretView that returns a secret message when accessed. This view is linked to the URL path 'secret/' in the urls.py file.

The vulnerability here is that there is no authentication mechanism in place to protect the SecretView. This means any user, authenticated or not, can access this view by simply navigating to the '/secret' URL. This poses a significant security risk as sensitive information could be exposed to unauthorized users.

In a real-world scenario, such a view could contain sensitive user information, confidential business data, or functionality that should only be accessible by authenticated users. Without an authentication check, an attacker could easily access this information or functionality without needing to have an active session, leading to potential data breaches or unauthorized actions.

Steps​

  • Implement an authentication mechanism using Django's built-in authentication system.
  • Use Django's login_required decorator or LoginRequiredMixin to ensure that only authenticated users can access the view.
  • Apply the decorator or mixin to the SecretView.
  • Ensure that the authentication mechanism cannot be bypassed by testing it thoroughly.

Compliant code​

from django.http import HttpResponse
from django.contrib.auth.mixins import LoginRequiredMixin
from django.views import View

class SecretView(LoginRequiredMixin, View):
    def get(self, request):
        return HttpResponse('This is a secret view')

# In urls.py
from django.urls import path
from .views import SecretView

urlpatterns = [
    path('secret/', SecretView.as_view(), name='secret'),
]

The updated code now includes Django's built-in authentication system. The LoginRequiredMixin is a built-in Django mixin that ensures a user is authenticated before they can access the view it's applied to.

In the updated code, LoginRequiredMixin is added as a parent class to SecretView. This means that before the get method of SecretView is called, Django will first check if the user is authenticated. If the user is not authenticated, they will be redirected to the login page. Only after a successful login can the user access the 'secret' view.

This effectively prevents unauthenticated access to the 'secret' view, addressing the vulnerability in the original code.

Remember to test the updated code thoroughly to ensure the authentication mechanism works as expected and cannot be bypassed.

References​

Last updated on