CVE-2016-9539 in macOS
Summary
by MITRE
tools/tiffcrop.c in libtiff 4.0.6 has an out-of-bounds read in readContigTilesIntoBuffer(). Reported as MSVR 35092.
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Analysis
by VulDB Data Team • 11/02/2024
The vulnerability identified as CVE-2016-9539 resides within the libtiff library version 4.0.6, specifically in the tools/tiffcrop.c file where the readContigTilesIntoBuffer() function exhibits an out-of-bounds read condition. This issue manifests when processing TIFF image files that contain malformed or specially crafted tile data structures. The flaw represents a classic buffer over-read vulnerability that can potentially lead to information disclosure or system instability when the affected library processes untrusted input files.
The technical implementation of this vulnerability stems from inadequate bounds checking within the tile reading logic of the tiffcrop utility. When the readContigTilesIntoBuffer() function attempts to read tile data into a buffer, it fails to properly validate the size parameters associated with tile dimensions and data offsets. This allows an attacker to craft a malicious TIFF file where tile data structures contain incorrect size values or overlapping memory references that cause the function to read beyond the allocated buffer boundaries. The out-of-bounds read occurs during the processing of contiguous tile data, which is a common format used in TIFF images for storing raster data.
From an operational perspective, this vulnerability presents significant security implications for systems that utilize libtiff for image processing tasks, particularly in environments where untrusted TIFF files are processed. The vulnerability can be exploited through various attack vectors including web applications that accept image uploads, document processing systems, or any software that incorporates libtiff functionality for TIFF file handling. The impact extends beyond simple information disclosure as the out-of-bounds read could potentially be leveraged to trigger more severe consequences such as denial of service or, in some cases, code execution depending on the specific system configuration and memory layout.
The vulnerability maps to CWE-125: Out-of-bounds Read within the Common Weakness Enumeration catalog, which specifically addresses situations where programs access memory locations beyond the boundaries of allocated buffers. This weakness is particularly dangerous in image processing libraries where input validation is critical due to the complex and varied nature of image file formats. The ATT&CK framework categorizes this type of vulnerability under T1203: Exploitation for Client Execution when it leads to arbitrary code execution, or T1499: Endpoint Denial of Service when it results in system instability. Organizations using affected versions of libtiff should prioritize patching and implementing input validation measures to prevent exploitation of this vulnerability. The recommended mitigation includes upgrading to libtiff version 4.0.7 or later where the bounds checking has been properly implemented to prevent the out-of-bounds read condition. Additionally, deploying defensive measures such as input sanitization, file format validation, and restricting file processing to trusted sources can help reduce the attack surface for this vulnerability.