Delivering code in production with debug features activated is security-sensitive. It has led in the past to the following vulnerabilities:

An application's debug features enable developers to find bugs more easily. It often gives access to detailed information on both the system running the application and users. Sometime it even enables the execution of custom commands. Thus deploying on production servers an application which has debug features activated is extremely dangerous.

Ask Yourself Whether

You are at risk if you answered yes to any of these questions.

Recommended Secure Coding Practices

The application should run by default in the most secure mode, i.e. as on production servers. This is to prevent any mistake. Enabling debug features should be explicitly asked via a command line argument, an environment variable or a configuration file.

Check that every debug feature is controlled by only very few configuration variables: logging, exception/error handling, access control, etc... It is otherwise very easy to forget one of them.

Do not enable debug features on production servers.

Sensitive Code Example

Django

from django.conf import settings

settings.configure(DEBUG=True)  # Sensitive when set to True
settings.configure(DEBUG_PROPAGATE_EXCEPTIONS=True)  # Sensitive when set to True

def custom_config(config):
    settings.configure(default_settings=config, DEBUG=True)  # Sensitive

Django's "global_settings.py" configuration file

# NOTE: The following code raises issues only if the file is named "global_settings.py". This is the default
# name of Django configuration file

DEBUG = True  # Sensitive
DEBUG_PROPAGATE_EXCEPTIONS = True  # Sensitive

See