Overview
This guide addresses Improper Inventory Management as demonstrated by CVE-2007-5712 in Django. The vulnerability arises when the internationalization (i18n) framework is enabled and the system accepts unbounded or poorly bounded input from the client, leading to resource exhaustion. In the Django cases cited (0.91, 0.95, 0.95.1, 0.96), and in integrations like PyLucid, an attacker could trigger a denial of service by sending many HTTP requests with excessively large Accept-Language headers. The underlying issue is failure to cap or safely parse external inputs that influence resource allocation, effectively a file/headers-based DoS via improper input handling (CWE-399). This class of vulnerability highlights the importance of bounded input handling in inventorying and controlling resource consumption per request. The remediated pattern should involve upgrading to patched releases and adding explicit guards to prevent unbounded header processing, thereby stabilizing memory usage under load.
Affected Versions
Django 0.91, 0.95, 0.95.1, 0.96; PyLucid and other products using i18n with USE_I18N enabled.
Code Fix Example
Django API Security Remediation
VULNERABLE PATTERN (Django LocaleMiddleware under i18n enabled):
from django.utils import translation
from django.utils.deprecation import MiddlewareMixin
class VulnerableLocaleMiddleware(translation.LocaleMiddleware):
def process_request(self, request):
# Locale selection based on Accept-Language can be exploited with very long headers
translation.get_language_from_request(request)
FIXED PATTERN (Guard Accept-Language length before Django processes it):
from django.utils import translation
from django.utils.deprecation import MiddlewareMixin
class PatchedLocaleMiddleware(MiddlewareMixin):
def process_request(self, request):
max_len = 1024 # Bound the header length to prevent memory exhaustion
lang_header = request.META.get('HTTP_ACCEPT_LANGUAGE', '')
if len(lang_header) > max_len:
lang_header = lang_header[:max_len]
request.META['HTTP_ACCEPT_LANGUAGE'] = lang_header
translation.get_language_from_request(request)