Insecure encryption algorithm - SSL/TLS - Python

Insecure encryption algorithm - SSL/TLS - Python

Need

Implementation of secure encryption algorithms and disabling insecure TLS protocol versions

Context

  • Usage of Python 3 for general-purpose programming and scripting
  • Usage of Django for building web applications
  • Usage of OpenSSL for secure communication and encryption

Description

Non compliant code

        from django.core.servers.basehttp import get_internal_wsgi_application

wsgi_application = get_internal_wsgi_application()

from OpenSSL import SSL
context = SSL.Context(SSL.SSLv23_METHOD)
context.use_privatekey_file('server.key')
context.use_certificate_file('server.crt')

from django.core.servers.basehttp import run
run("localhost", 8000, wsgi_application, '', context)

This Python code snippet represents a Django server configured to use an insecure TLS protocol version. The OpenSSL library is used to create an SSL context for the server
- the context is essentially a configuration of the SSL settings.

The SSL context is created with the SSL.SSLv23_METHOD method, which allows the server to negotiate with clients using any SSL or TLS protocol version. This includes insecure versions of the protocols, such as SSLv2, SSLv3, TLSv1.0, and TLSv1.1.

The server's private key and certificate are set with the use_privatekey_file and use_certificate_file methods, respectively.

Finally, the Django server is run with the run method, which starts the server on localhost at port 8000. The server uses the insecure SSL context for its connections.

This code is vulnerable because it allows the server to use insecure protocol versions that are susceptible to various attacks, such as the POODLE attack (for SSLv3) and the BEAST attack (for TLSv1.0).

Steps

  • Replace the insecure SSLv23_METHOD with a more secure version such as TLSv1_2_METHOD or TLSv1_3_METHOD.
  • Ensure that the server does not accept any SSL or early TLS versions by setting the options attribute of the context to SSL.OP_NO_SSLv2 and SSL.OP_NO_SSLv3.
  • Regularly update the OpenSSL library to the latest version to get the most recent security patches and updates.
  • Consider using a security configuration guide or tool to ensure the server is configured securely.

Compliant code

        from django.core.servers.basehttp import get_internal_wsgi_application
from OpenSSL import SSL

wsgi_application = get_internal_wsgi_application()

context = SSL.Context(SSL.TLSv1_2_METHOD) # Use a secure version of TLS
context.use_privatekey_file('server.key')
context.use_certificate_file('server.crt')

# Ensure the server does not accept any SSL or early TLS versions
context.set_options(SSL.OP_NO_SSLv2)
context.set_options(SSL.OP_NO_SSLv3)

from django.core.servers.basehttp import run
run("localhost", 8000, wsgi_application, '', context)

The original code was using an insecure SSLv23_METHOD for the SSL Context, which allows the usage of insecure TLS protocol versions. This can lead to vulnerabilities where an attacker can exploit these insecure protocols to compromise the server.

The updated code uses a more secure version of TLS, specifically TLSv1_2_METHOD. This ensures that the server is using a secure version of the TLS protocol.

Additionally, the options attribute of the context is set to SSL.OP_NO_SSLv2 and SSL.OP_NO_SSLv3. This ensures that the server does not accept any SSL or early TLS versions, further enhancing the security of the server.

It's also recommended to regularly update the OpenSSL library to the latest version to get the most recent security patches and updates.

Consider using a security configuration guide or tool to ensure the server is configured securely. This can help prevent potential vulnerabilities and ensure the server is following best practices for security.

References