CVE-2017-18013 in LibTIFF
Summary
by MITRE
In LibTIFF 4.0.9, there is a Null-Pointer Dereference in the tif_print.c TIFFPrintDirectory function, as demonstrated by a tiffinfo crash.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-18013 represents a critical null-pointer dereference flaw within the LibTIFF library version 4.0.9, specifically affecting the TIFFPrintDirectory function in the tif_print.c source file. This issue manifests when processing malformed TIFF image files, leading to a crash condition that can be exploited by malicious actors to disrupt service availability or potentially execute arbitrary code. The vulnerability stems from insufficient input validation and error handling within the print directory functionality that processes TIFF metadata structures. The flaw occurs when the function attempts to dereference a pointer that has not been properly initialized or validated, creating a condition where the application crashes upon encountering certain malformed data structures within the TIFF file format.
The technical implementation of this vulnerability aligns with CWE-476, which categorizes null pointer dereference conditions as a fundamental programming error that can lead to application instability and potential security implications. When a TIFF file contains malformed or corrupted directory entries, the TIFFPrintDirectory function fails to properly validate pointer references before accessing them, resulting in a segmentation fault or access violation. This behavior is particularly concerning because TIFF files are commonly used in document management systems, image processing applications, and digital asset management platforms where automated processing is prevalent. The vulnerability demonstrates poor defensive programming practices where proper null checks and error handling mechanisms are absent or inadequate, allowing malformed input to propagate through the system without proper sanitization.
Operationally, this vulnerability presents significant risks to organizations that process TIFF files automatically, particularly in environments where file validation is not performed before processing. The crash condition can be reliably triggered through specially crafted TIFF files, making it suitable for denial-of-service attacks against applications that depend on LibTIFF for image processing. Attackers could potentially exploit this vulnerability by uploading malicious TIFF files to web applications or file processing systems, causing service interruptions and potentially creating opportunities for more sophisticated attacks. The impact extends beyond simple service disruption, as the vulnerability could be leveraged in broader attack chains where system stability is compromised, potentially enabling further exploitation or escalation of privileges. Security monitoring systems may also be affected as the crash can generate unusual network traffic patterns or system alerts that could be misinterpreted as legitimate operational events.
The recommended mitigation strategy involves upgrading to LibTIFF version 4.0.10 or later, where the null-pointer dereference has been addressed through proper input validation and pointer initialization checks. Organizations should implement comprehensive file validation procedures that include signature verification and format compliance checking before processing TIFF files in automated workflows. Additionally, deploying network-based intrusion detection systems and implementing application-level sandboxing for TIFF processing can provide additional layers of protection against exploitation attempts. The vulnerability highlights the importance of maintaining current software versions and implementing robust input validation mechanisms as part of secure coding practices. Organizations should also consider implementing automated patch management processes to ensure timely deployment of security updates and reduce the window of exposure to known vulnerabilities. Security teams should monitor for exploitation attempts and maintain detailed logging of file processing activities to detect potential abuse of this vulnerability in production environments.