CVE-2017-9935 in LibTIFF
Summary
by MITRE
In LibTIFF 4.0.8, there is a heap-based buffer overflow in the t2p_write_pdf function in tools/tiff2pdf.c. This heap overflow could lead to different damages. For example, a crafted TIFF document can lead to an out-of-bounds read in TIFFCleanup, an invalid free in TIFFClose or t2p_free, memory corruption in t2p_readwrite_pdf_image, or a double free in t2p_free. Given these possibilities, it probably could cause arbitrary code execution.
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability identified as CVE-2017-9935 represents a critical heap-based buffer overflow within the LibTIFF library version 4.0.8, specifically within the t2p_write_pdf function located in the tools/tiff2pdf.c file. This flaw arises from inadequate bounds checking during the processing of TIFF to PDF conversion operations, creating a scenario where maliciously crafted input can trigger memory corruption. The vulnerability falls under CWE-121, heap-based buffer overflow, which is a well-documented weakness in software systems that handle memory allocation and deallocation without proper validation of input boundaries.
The technical execution of this vulnerability occurs when the t2p_write_pdf function processes malformed TIFF files that contain crafted data structures designed to exceed the allocated buffer boundaries. This overflow can manifest in multiple dangerous behaviors including out-of-bounds reads within the TIFFCleanup function, invalid memory free operations in TIFFClose or t2p_free, memory corruption during t2p_readwrite_pdf_image processing, and potentially dangerous double free conditions in the t2p_free routine. These memory corruption scenarios create opportunities for attackers to manipulate the program's execution flow and potentially achieve arbitrary code execution. The vulnerability demonstrates characteristics consistent with the attack pattern described in ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands on affected systems.
The operational impact of CVE-2017-9935 extends beyond simple denial of service conditions to potentially enable complete system compromise. Systems that process TIFF files through the affected LibTIFF library, including document management systems, image processing applications, and PDF generation tools, become vulnerable to remote code execution attacks. The vulnerability is particularly concerning because it can be triggered through simple file processing operations, making it accessible to attackers who can craft malicious TIFF files for distribution. This makes the vulnerability suitable for exploitation in phishing campaigns, web-based attacks, or any scenario where users might encounter TIFF files from untrusted sources. The memory corruption patterns associated with this vulnerability align with the exploitation techniques described in the Common Exploitation Techniques framework, where buffer overflows are commonly leveraged to achieve privilege escalation and persistent system compromise.
Mitigation strategies for CVE-2017-9935 should prioritize immediate patching of affected LibTIFF installations to version 4.0.9 or later, which contains the necessary fixes for the heap overflow conditions. Organizations should implement input validation controls to sanitize TIFF files before processing, particularly when these files originate from untrusted sources. Network segmentation and access controls can help limit the potential impact of successful exploitation attempts, while monitoring systems should be configured to detect unusual file processing activities that might indicate exploitation attempts. Additionally, application whitelisting and sandboxing techniques can provide defense-in-depth measures to prevent malicious code execution even if the vulnerability is successfully exploited. The vulnerability serves as a reminder of the critical importance of proper memory management and input validation in security-critical libraries, particularly those handling multimedia file formats that are commonly processed in enterprise environments.