CVE-2017-17095 in LibTIFF
Summary
by MITRE
tools/pal2rgb.c in pal2rgb in LibTIFF 4.0.7 allows remote attackers to cause a denial of service (TIFFSetupStrips heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted TIFF file.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2017-17095 represents a critical heap-based buffer overflow in the pal2rgb component of LibTIFF version 4.0.7, specifically within the tools/pal2rgb.c file. This flaw occurs during the processing of TIFF image files when the application attempts to convert palette-based images to RGB format through the TIFFSetupStrips function. The vulnerability arises from insufficient input validation and boundary checking when handling crafted malicious TIFF files that contain malformed palette data structures. Attackers can exploit this weakness by preparing specially constructed TIFF files that trigger the buffer overflow condition during the image processing pipeline, leading to unpredictable application behavior.
The technical implementation of this vulnerability stems from improper memory management practices within the TIFF library's palette handling routines. When the pal2rgb utility processes a TIFF file with malformed palette entries, the application fails to properly validate the size and structure of palette data before attempting to copy or manipulate this information into heap-allocated buffers. This lack of input sanitization creates a condition where an attacker-controlled data stream can overwrite adjacent memory locations, potentially corrupting heap metadata or executing arbitrary code. The vulnerability manifests as a heap-based buffer overflow because the application allocates memory dynamically for palette data but does not verify that the incoming data fits within the allocated buffer boundaries. This flaw aligns with CWE-121, heap-based buffer overflow, and represents a classic example of inadequate bounds checking in memory management operations.
The operational impact of CVE-2017-17095 extends beyond simple denial of service to potentially enable more sophisticated attack vectors. Remote attackers can leverage this vulnerability to cause application crashes, resulting in service disruption for systems that rely on LibTIFF for image processing tasks. In environments where applications automatically process user-uploaded TIFF files, this vulnerability creates a significant risk for denial of service attacks that can target web applications, image servers, or document processing systems. The unspecified other impacts mentioned in the CVE description suggest that under certain conditions, the buffer overflow could potentially be exploited to execute arbitrary code or escalate privileges, making this vulnerability particularly dangerous in multi-tenant or public-facing applications. The vulnerability affects any system running LibTIFF 4.0.7 or earlier versions where TIFF file processing is enabled, including web servers, image processing pipelines, and document management systems.
Mitigation strategies for CVE-2017-17095 should focus on immediate patching and input validation measures. The most effective solution involves upgrading to LibTIFF version 4.0.8 or later, where the vulnerability has been addressed through proper bounds checking and input validation in the palette processing routines. Organizations should implement comprehensive input validation for all TIFF file processing operations, including size verification, structure validation, and content sanitization before any image conversion processes begin. Additional protective measures include deploying network-based intrusion detection systems to monitor for suspicious TIFF file patterns, implementing application-level sandboxing for image processing tasks, and configuring automatic file type validation to reject malformed or suspicious image files. From an ATT&CK framework perspective, this vulnerability maps to techniques involving execution through libraries and privilege escalation through memory corruption, emphasizing the need for both defensive and monitoring controls to prevent exploitation. System administrators should also consider implementing least privilege principles for image processing services and regularly audit image handling workflows to identify potential attack vectors that could leverage similar memory corruption vulnerabilities.