CVE-2016-10371 in LibTIFF
Summary
by MITRE
The TIFFWriteDirectoryTagCheckedRational function in tif_dirwrite.c in LibTIFF 4.0.6 allows remote attackers to cause a denial of service (assertion failure and application exit) via a crafted TIFF file.
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Analysis
by VulDB Data Team • 10/17/2019
The vulnerability identified as CVE-2016-10371 resides within the LibTIFF library version 4.0.6, specifically within the TIFFWriteDirectoryTagCheckedRational function located in the tif_dirwrite.c source file. This flaw represents a classic denial of service vulnerability that can be exploited by remote attackers through the careful crafting of malicious TIFF image files. The vulnerability manifests when the library processes specially constructed TIFF files that trigger an assertion failure, leading to abrupt application termination and system unavailability. The affected function operates within the TIFF directory writing mechanism, which is responsible for handling metadata and directory structures within TIFF image files, making it a critical component in image processing workflows across numerous applications and systems.
The technical exploitation of this vulnerability occurs when a malicious TIFF file contains malformed rational number values that are processed by the TIFFWriteDirectoryTagCheckedRational function. This function performs validation checks on rational numbers used in TIFF directory tags, but fails to properly handle certain edge cases or malformed inputs that cause the assertion mechanism to fail. The assertion failure occurs during the directory writing process when the library encounters unexpected rational number formats or values that exceed expected ranges, triggering a program exit that terminates the application. This behavior aligns with CWE-617, which classifies assertion failures that can be triggered by external input as a weakness that leads to denial of service conditions. The vulnerability demonstrates a clear lack of proper input validation and error handling within the library's directory writing routines, creating an exploitable path where external inputs can directly influence program execution flow.
From an operational impact perspective, this vulnerability can significantly disrupt services that rely on LibTIFF for image processing, including web applications, content management systems, digital asset management platforms, and image processing pipelines. The remote nature of the attack means that adversaries can exploit this vulnerability without requiring physical access to the target system, making it particularly dangerous in networked environments where TIFF files are processed automatically. When exploited successfully, the vulnerability causes immediate application termination, potentially leading to service outages, data processing interruptions, and cascading failures in systems that depend on continuous image processing capabilities. The impact extends beyond simple availability issues as it can affect business continuity, particularly in environments where automated image processing workflows are critical to operations, with potential financial implications from service disruptions and the need for emergency patching procedures.
The mitigation strategies for this vulnerability primarily involve updating to patched versions of the LibTIFF library where the assertion failure has been addressed through improved input validation and error handling mechanisms. System administrators should prioritize patching affected systems, particularly those processing untrusted TIFF files from external sources. Additional defensive measures include implementing proper input validation at application layers, deploying file type checking mechanisms, and establishing sandboxed processing environments for TIFF files. Organizations should also consider implementing network-level controls to restrict access to vulnerable services and employ intrusion detection systems that can identify potential exploitation attempts. From a security framework perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates the importance of robust input validation as outlined in the OWASP Top Ten security principles. The vulnerability serves as a reminder of the critical need for proper error handling and input validation in widely-used library components that process untrusted data, as even seemingly minor flaws can lead to significant operational disruptions and security incidents.