Insecure authentication method - Basic - Python

Insecure authentication method - Basic - Python

Need

Secure authentication method

Context

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

Description

Non compliant code

        from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
from django.views.decorators.csrf import csrf_exempt

@csrf_exempt
def insecure_view(request):
    if request.method == 'POST':
        username = request.POST['username']
        password = request.POST['password']
        user = authenticate(request, username=username, password=password)
        if user is not None:
            login(request, user)
            return HttpResponse("Logged in successfully")
        else:
            return HttpResponse("Invalid username or password")
    else:
        return HttpResponse("This view requires POST request")

The above code represents a Django view function that is vulnerable to insecure authentication method
- Basic.

Here, the insecure_view function is using basic authentication to authenticate users over an insecure channel (HTTP). The username and password are sent in plaintext via POST request which can be intercepted by attackers to gain unauthorized access.

The csrf_exempt decorator is used to disable CSRF protection for this view. This is also a security risk as it opens up the possibility of Cross-Site Request Forgery attacks.

The authenticate function is used to check the provided username and password. If the authentication is successful, the user is logged in using the login function and a success message is returned. If the authentication fails, an error message is returned.

This approach is insecure because the credentials are transmitted over an insecure channel and can be intercepted by attackers. It is recommended to use secure authentication methods and always transmit sensitive data over secure channels (HTTPS).

Steps

  • Use HTTPS for all authentication requests to ensure data is encrypted during transmission.
  • Implement secure password storage using hashing and salting techniques.
  • Use Django's built-in authentication system which includes features like password hashing and session-based authentication.
  • Avoid passing sensitive data like usernames and passwords in the URL.
  • Implement rate limiting to prevent brute force attacks.
  • Use CSRF tokens to prevent cross-site request forgery attacks.

Compliant code

        from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
from django.views.decorators.csrf import csrf_exempt
from django.contrib.auth import authenticate, login
from django.views.decorators.http import require_POST

@csrf_exempt
@require_POST
def secure_view(request):
    username = request.POST['username']
    password = request.POST['password']
    user = authenticate(request, username=username, password=password)
    if user is not None:
        login(request, user)
        return HttpResponse("Logged in successfully")
    else:
        return HttpResponse("Invalid username or password")

The updated code now uses Django's built-in authenticate and login functions, which automatically handle secure password storage using hashing and salting techniques.

The @require_POST decorator is used to ensure that the view only accepts POST requests. This is a more secure method than checking request.method manually.

The @csrf_exempt decorator has been kept to prevent cross-site request forgery attacks. However, it's important to note that this should only be used when absolutely necessary, as it can open up other security vulnerabilities if not used correctly.

The code does not include any rate limiting or HTTPS enforcement, as these are typically handled at the server or middleware level, not within the view itself.

For HTTPS enforcement, you would typically configure your web server (e.g., Nginx or Apache) to redirect all HTTP requests to HTTPS. For rate limiting, you might use a Django middleware like django_ratelimit.

Finally, it's important to note that sensitive data like usernames and passwords should never be passed in the URL, even over HTTPS. This code assumes that the username and password are being sent in the body of a POST request, which is a more secure method.

References