CVE-2013-0306 in Django
Summary
by MITRE
The form library in Django 1.3.x before 1.3.6, 1.4.x before 1.4.4, and 1.5 before release candidate 2 allows remote attackers to bypass intended resource limits for formsets and cause a denial of service (memory consumption) or trigger server errors via a modified max_num parameter.
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Analysis
by VulDB Data Team • 01/02/2022
The vulnerability identified as CVE-2013-0306 represents a critical denial of service weakness within the Django web framework's form processing capabilities. This issue affects multiple versions of Django including 1.3.x prior to 1.3.6, 1.4.x prior to 1.4.4, and versions before the release candidate 2 of Django 1.5. The flaw resides in the form library's handling of formset parameters, specifically the max_num parameter that controls the maximum number of forms that can be processed within a formset. This vulnerability exposes the framework to potential abuse through crafted malicious requests that manipulate formset limits.
The technical implementation of this vulnerability stems from insufficient input validation and parameter sanitization within Django's formset handling mechanism. When attackers modify the max_num parameter in formset requests, the framework fails to properly validate these values against expected ranges or resource constraints. This allows adversaries to submit requests with extremely high or negative values for max_num, causing the application to allocate excessive memory resources or trigger internal server errors. The vulnerability operates at the application layer and can be exploited through HTTP requests that contain manipulated formset parameters, making it particularly dangerous for web applications that rely heavily on Django's form processing capabilities.
The operational impact of CVE-2013-0306 extends beyond simple service disruption to potentially compromise entire application availability. When exploited, this vulnerability can cause significant memory consumption patterns that may lead to application crashes, server resource exhaustion, or complete denial of service conditions for legitimate users. The memory consumption aspect particularly affects applications running in constrained environments where memory resources are limited. Additionally, the vulnerability can trigger server errors that may expose internal application details or cause cascading failures in applications that depend on Django's formset functionality. This makes the vulnerability particularly dangerous in production environments where application stability and resource management are critical concerns.
Organizations affected by this vulnerability should immediately implement mitigation strategies including updating to patched versions of Django where available. The recommended approach involves upgrading to Django 1.3.6, 1.4.4, or the appropriate release candidate for Django 1.5. Beyond version updates, administrators should implement additional defensive measures such as input validation for formset parameters, rate limiting on form processing endpoints, and monitoring for unusual patterns in formset request parameters. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how insufficient parameter validation can lead to resource exhaustion attacks. From an ATT&CK perspective, this vulnerability maps to the denial of service technique category and could be leveraged as part of broader reconnaissance or exploitation campaigns targeting web applications. Security teams should also consider implementing network-level controls to detect and block suspicious formset parameter modifications while maintaining proper logging and monitoring to identify potential exploitation attempts.