CVE-2012-3443 in django
Summary
by MITRE
The django.forms.ImageField class in the form system in Django before 1.3.2 and 1.4.x before 1.4.1 completely decompresses image data during image validation, which allows remote attackers to cause a denial of service (memory consumption) by uploading an image file.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability identified as CVE-2012-3443 affects the Django web framework's form handling system, specifically the ImageField class implementation. This issue exists in Django versions prior to 1.3.2 and 1.4.x versions before 1.4.1, representing a critical security flaw that can be exploited remotely. The vulnerability stems from how the framework processes image validation, creating a significant risk for applications that utilize image upload functionality. Attackers can leverage this weakness to consume excessive system resources, potentially leading to complete service unavailability.
The technical flaw manifests in the image validation process where the django.forms.ImageField class performs complete decompression of image data regardless of the actual file format or size constraints. This behavior is particularly problematic because it processes all image data without proper resource limits or checks, allowing malicious actors to upload specially crafted image files that trigger excessive memory consumption during validation. The implementation does not employ any form of memory or time-based constraints during decompression operations, making it susceptible to exploitation through carefully constructed input files.
The operational impact of this vulnerability is severe, as it enables remote attackers to execute a denial of service attack against Django applications. When an attacker uploads an image file that triggers the decompression process, the system consumes progressively increasing amounts of memory until the application becomes unresponsive or crashes entirely. This type of attack can be particularly devastating in production environments where multiple concurrent users might be uploading images, as it can quickly exhaust available system resources and impact legitimate users. The vulnerability affects any Django application that utilizes the ImageField class for file uploads, making it a widespread concern across numerous web applications.
Mitigation strategies for this vulnerability include upgrading to Django versions 1.3.2 or 1.4.1 and later, which contain patches addressing the excessive decompression behavior. Organizations should also implement additional safeguards such as setting strict file size limits, implementing proper input validation, and configuring resource limits on image processing components. The vulnerability aligns with CWE-400, which addresses unspecified resource management issues, and can be categorized under ATT&CK technique T1499.004 for resource exhaustion attacks. Security teams should also consider implementing network-level protections and monitoring for unusual memory consumption patterns that might indicate exploitation attempts.