CVE-2016-0775 in Pillow
Summary
by MITRE
Buffer overflow in the ImagingFliDecode function in libImaging/FliDecode.c in Pillow before 3.1.1 allows remote attackers to cause a denial of service (crash) via a crafted FLI file.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2016-0775 represents a critical buffer overflow flaw within the Pillow library's image processing capabilities, specifically affecting the ImagingFliDecode function located in libImaging/FliDecode.c. This issue impacts versions of Pillow prior to 3.1.1 and exposes systems to remote attack vectors that can trigger denial of service conditions through maliciously crafted FLI (Flash Light Image) files. The FLI format is a proprietary image format originally developed for Autodesk Animator and later adopted by other applications, making this vulnerability particularly concerning for systems that process untrusted image data from external sources.
The technical nature of this vulnerability stems from inadequate input validation within the FLI file parsing logic where the ImagingFliDecode function fails to properly bounds-check buffer allocations when processing image data. When a specially crafted FLI file is processed, the function attempts to write data beyond the allocated memory boundaries, causing memory corruption that ultimately results in application crashes. This type of buffer overflow vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and represents a classic example of unsafe memory manipulation practices in image parsing libraries. The vulnerability operates at the intersection of image processing and memory safety, where the parsing of malformed image data triggers undefined behavior through improper memory access patterns.
The operational impact of this vulnerability extends beyond simple denial of service to potentially create broader security implications within systems that rely on Pillow for image processing tasks. Attackers can exploit this weakness by delivering malicious FLI files through various attack vectors including web applications, email attachments, or file sharing systems, leading to service disruption for legitimate users. The vulnerability is particularly dangerous in web environments where image upload functionality is common, as it allows remote code execution potential in some scenarios. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or cause service disruption, and demonstrates the importance of proper input sanitization in image processing pipelines.
Mitigation strategies for CVE-2016-0775 primarily focus on immediate version updates to Pillow 3.1.1 or later, which contain the necessary patches to address the buffer overflow conditions. System administrators should prioritize patching affected installations and implement additional defensive measures such as input validation, file type restrictions, and sandboxed image processing environments. Organizations should also consider implementing network-based intrusion detection systems to monitor for suspicious image file patterns and establish robust image processing security policies that include regular security assessments of image handling components. The vulnerability underscores the critical importance of maintaining up-to-date third-party libraries and implementing comprehensive security testing procedures for image processing workflows, particularly in environments where untrusted content is regularly processed.