CVE-2018-7456 in LibTIFF
Summary
by MITRE
A NULL Pointer Dereference occurs in the function TIFFPrintDirectory in tif_print.c in LibTIFF 4.0.9 when using the tiffinfo tool to print crafted TIFF information, a different vulnerability than CVE-2017-18013. (This affects an earlier part of the TIFFPrintDirectory function that was not addressed by the CVE-2017-18013 patch.)
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7456 represents a critical null pointer dereference flaw within the LibTIFF library version 4.0.9, specifically within the TIFFPrintDirectory function located in the tif_print.c source file. This issue manifests when the tiffinfo utility processes specially crafted TIFF image files, creating a scenario where the application attempts to access memory through a null pointer reference. The vulnerability operates at the intersection of software robustness and input validation, where the library fails to properly validate the structure of TIFF metadata before attempting to process it, leading to a potential application crash or denial of service condition.
The technical implementation of this vulnerability stems from inadequate input validation within the TIFFPrintDirectory function, which is responsible for formatting and displaying TIFF file directory information. When processing malformed TIFF files, the function does not adequately check for null pointer conditions before dereferencing pointers that may not have been properly initialized or allocated. This flaw specifically affects an earlier section of the function that was not covered by the previous CVE-2017-18013 patch, indicating a pattern of similar vulnerabilities within the same codebase. The null pointer dereference occurs during the directory printing process, where the application attempts to traverse TIFF directory structures without proper validation of pointer integrity, creating an execution path that leads to memory access violations.
From an operational perspective, this vulnerability presents a significant risk to systems that rely on LibTIFF for image processing and manipulation, particularly in environments where untrusted TIFF files are processed automatically. The impact extends beyond simple application crashes to potentially enable more sophisticated attack vectors, as the null pointer dereference could be exploited to cause system instability or provide a foothold for further exploitation. The vulnerability affects the tiffinfo tool specifically, which is commonly used for examining TIFF file contents, but the underlying flaw exists within the library itself, meaning any application that utilizes LibTIFF for TIFF file processing could be susceptible to similar issues. This makes the vulnerability particularly concerning in enterprise environments where automated image processing pipelines are common, as a single malformed file could disrupt critical operations.
The security implications of CVE-2018-7456 align with CWE-476, which specifically addresses NULL Pointer Dereference conditions in software systems, and can be categorized under ATT&CK technique T1203, which involves the exploitation of software vulnerabilities to gain system access. Mitigation strategies should focus on immediate patching of affected LibTIFF versions, implementing input validation measures for TIFF file processing, and deploying sandboxing techniques for untrusted file handling. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of exploitation, while monitoring for any suspicious file processing activities that might indicate attempted exploitation of this vulnerability.
This vulnerability demonstrates the importance of comprehensive code review processes and the need for robust input validation mechanisms in multimedia processing libraries. The fact that it affects an earlier portion of the code not addressed by a previous patch highlights the challenges in maintaining software security over time, particularly in complex libraries that handle multiple file formats and processing paths. The vulnerability serves as a reminder of the critical nature of maintaining up-to-date security patches and the necessity of thorough regression testing when addressing security vulnerabilities in widely-used software components.