CVE-2016-4009 in Pillow
Summary
by MITRE
Integer overflow in the ImagingResampleHorizontal function in libImaging/Resample.c in Pillow before 3.1.1 allows remote attackers to have unspecified impact via negative values of the new size, which triggers a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2016-4009 represents a critical integer overflow flaw within the Pillow image processing library, specifically affecting the ImagingResampleHorizontal function located in libImaging/Resample.c. This issue exists in versions prior to 3.1.1 and poses significant security risks to systems that process untrusted image data. The vulnerability stems from improper handling of negative size parameters during image resampling operations, creating conditions where maliciously crafted input can trigger unexpected behavior in memory management. The flaw manifests when negative values are passed as new size parameters, leading to calculations that exceed the bounds of integer data types and subsequently cause heap-based buffer overflows.
The technical implementation of this vulnerability involves the manipulation of integer arithmetic within the image resampling pipeline where the function fails to validate input parameters properly. When negative size values are provided, the integer overflow occurs during calculations that determine buffer allocation sizes, resulting in insufficient memory allocation that can be exploited to overwrite adjacent memory regions. This type of vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which is classified as a common weakness in software security practices. The flaw demonstrates poor input validation and memory management practices that are particularly dangerous in image processing libraries that handle diverse and potentially malicious input from various sources.
The operational impact of CVE-2016-4009 extends beyond simple denial of service scenarios, as the heap-based buffer overflow can potentially enable remote code execution or arbitrary code execution depending on the specific system configuration and memory layout. Attackers can leverage this vulnerability by crafting specially formatted image files that contain negative size parameters, which when processed by vulnerable Pillow versions can trigger the overflow condition. The vulnerability affects web applications, content management systems, and any software that relies on Pillow for image processing, making it particularly dangerous in environments where users can upload images or where image processing is performed on external content. This type of vulnerability aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where attackers exploit software vulnerabilities to execute malicious code.
Mitigation strategies for this vulnerability require immediate patching of affected Pillow installations to version 3.1.1 or later, which includes proper input validation and bounds checking for size parameters. Organizations should implement comprehensive input sanitization measures for all image processing pipelines, particularly when handling untrusted input from external sources. Additional defensive measures include implementing strict parameter validation, memory protection mechanisms, and regular security audits of image processing components. The vulnerability highlights the importance of proper integer handling and memory management in security-critical applications, emphasizing that even seemingly benign operations like image resizing can become attack vectors when proper bounds checking is not implemented. Security teams should monitor for exploitation attempts and ensure that all dependencies are regularly updated to address known vulnerabilities in image processing libraries and other third-party components.