CVE-2016-3076 in Pillow
Summary
by MITRE
Heap-based buffer overflow in the j2k_encode_entry function in Pillow 2.5.0 through 3.1.1 allows remote attackers to cause a denial of service (memory corruption) via a crafted Jpeg2000 file.
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Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2016-3076 represents a critical heap-based buffer overflow affecting the Pillow library version range from 2.5.0 through 3.1.1. This flaw exists within the j2k_encode_entry function, which processes JPEG2000 image files, creating a significant security risk for applications that utilize this library for image handling and processing. The vulnerability specifically targets the heap memory management during JPEG2000 encoding operations, where insufficient bounds checking allows malicious input to overwrite adjacent memory regions.
The technical implementation of this vulnerability stems from improper validation of input parameters within the JPEG2000 encoding pipeline. When a crafted malicious JPEG2000 file is processed by the vulnerable Pillow library, the j2k_encode_entry function fails to properly validate the size and structure of the incoming data before attempting to allocate memory for processing. This oversight creates a condition where the program writes data beyond the allocated buffer boundaries, leading to memory corruption that can result in arbitrary code execution or complete application crash. The vulnerability operates at the intersection of CWE-121 heap-based buffer overflow and CWE-787 out-of-bounds write, making it particularly dangerous for remote exploitation scenarios.
From an operational perspective, this vulnerability poses severe risks to web applications, content management systems, and any software platforms that accept user-uploaded image files. Attackers can leverage this flaw by uploading specifically crafted JPEG2000 files that trigger the buffer overflow during processing, resulting in denial of service conditions that can crash the application or potentially allow remote code execution. The impact extends beyond simple service disruption as the memory corruption can lead to unpredictable application behavior, data loss, or even system compromise depending on the execution environment and privilege levels. This vulnerability aligns with ATT&CK technique T1203, where adversaries exploit memory corruption vulnerabilities to gain unauthorized access or disrupt services.
The remediation strategy for CVE-2016-3076 requires immediate upgrading of the Pillow library to version 3.1.2 or later, which contains the necessary patches to address the buffer overflow condition. Organizations should also implement input validation measures to restrict or sanitize JPEG2000 file uploads, particularly in web applications where user-provided content is accepted. Additionally, deploying network segmentation and access controls can limit the potential impact of exploitation attempts. Security monitoring should include detection of unusual memory allocation patterns and process crashes that may indicate exploitation attempts. The fix implemented in the patched versions addresses the root cause by introducing proper bounds checking and memory allocation validation within the j2k_encode_entry function, preventing the overflow condition from occurring during JPEG2000 processing operations.