CVE-2018-8905 in LibTIFF
Summary
by MITRE
In LibTIFF 4.0.9, a heap-based buffer overflow occurs in the function LZWDecodeCompat in tif_lzw.c via a crafted TIFF file, as demonstrated by tiff2ps.
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Analysis
by VulDB Data Team • 02/22/2023
The vulnerability CVE-2018-8905 represents a critical heap-based buffer overflow within the LibTIFF library version 4.0.9, specifically within the LZWDecodeCompat function located in the tif_lzw.c source file. This flaw manifests when processing specially crafted TIFF image files that employ LZW compression algorithms, making it particularly dangerous given the widespread use of TIFF format across various applications and systems. The vulnerability is triggered during the decompression process when the library attempts to decode LZW-compressed data without proper bounds checking, leading to memory corruption that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the LZW decompression routine. When the LZWDecodeCompat function processes malformed TIFF files, it fails to properly validate the size of data structures before attempting to copy or manipulate memory regions. This allows an attacker to craft a TIFF file with maliciously constructed LZW compression data that causes the function to write beyond allocated buffer boundaries. The heap-based nature of the overflow means that the corruption occurs in dynamically allocated memory regions, potentially leading to arbitrary code execution or system crashes. This type of vulnerability aligns with CWE-121, heap-based buffer overflow, which specifically addresses buffer overflows occurring in heap memory regions.
The operational impact of CVE-2018-8905 extends beyond simple denial-of-service scenarios, as it can be leveraged for remote code execution when the vulnerable LibTIFF library is used in applications that process untrusted TIFF files. The vulnerability is particularly concerning because TIFF files are commonly used in document management systems, image processing software, and various enterprise applications that may automatically process files from untrusted sources. The demonstration using tiff2ps tool shows that even legitimate utility programs can become attack vectors when they utilize the vulnerable library. This creates a significant risk for organizations that rely on TIFF processing capabilities in their workflows, as a single malicious file could compromise entire systems or applications that depend on LibTIFF for image handling operations.
Mitigation strategies for CVE-2018-8905 should focus on immediate patching of affected LibTIFF versions, with version 4.0.10 and later containing the necessary fixes. Organizations should implement comprehensive input validation and sanitization measures for all TIFF file processing, particularly in environments where untrusted files may be encountered. Network segmentation and access controls can help limit the potential impact of exploitation attempts, while application whitelisting and sandboxing techniques can provide additional layers of protection. The vulnerability also highlights the importance of keeping third-party libraries updated and following secure coding practices that emphasize bounds checking and memory safety mechanisms. From an ATT&CK framework perspective, this vulnerability maps to techniques involving memory corruption exploits and can be classified under the initial access and execution phases of an attack lifecycle, making it a critical target for defensive measures and security monitoring.