CVE-2016-3990 in LibTIFF
Summary
by MITRE
Heap-based buffer overflow in the horizontalDifference8 function in tif_pixarlog.c in LibTIFF 4.0.6 and earlier allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted TIFF image to tiffcp.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2016-3990 represents a critical heap-based buffer overflow within the LibTIFF library's horizontalDifference8 function located in the tif_pixarlog.c file. This flaw affects LibTIFF versions 4.0.6 and earlier, making it a significant security concern for systems that process TIFF image files. The vulnerability arises from insufficient input validation and bounds checking within the pixel data processing routines that handle Pixar Log format TIFF files. When a maliciously crafted TIFF image is processed by applications using the affected LibTIFF library, particularly through the tiffcp utility, the buffer overflow can be triggered, leading to unpredictable system behavior.
The technical exploitation of this vulnerability occurs when the horizontalDifference8 function attempts to process pixel data without adequate verification of buffer boundaries. This function is specifically designed to handle the horizontal difference compression algorithm used in Pixar Log format TIFF files, but it fails to properly validate the size of incoming data against allocated buffer space. The flaw manifests as a heap-based buffer overflow, which means that the overflow occurs in heap memory rather than stack memory, making it particularly dangerous as it can be leveraged for more sophisticated attacks beyond simple denial of service. The vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of inadequate bounds checking in memory management operations. When exploited, this vulnerability can cause applications to crash due to memory corruption or potentially allow remote code execution if proper exploit mitigations are not in place.
The operational impact of CVE-2016-3990 extends beyond simple application crashes, as it can be leveraged for remote code execution in scenarios where vulnerable applications process untrusted TIFF input. Systems that rely on LibTIFF for image processing, including web applications, document management systems, and image processing pipelines, are at risk when they handle TIFF files from untrusted sources. The vulnerability affects the tiffcp utility specifically, but any application that utilizes the affected LibTIFF library functions can be compromised. This includes content management systems, digital asset management platforms, and various imaging applications that may automatically process uploaded TIFF files. The attack vector requires remote exploitation through a crafted TIFF image file, making it particularly dangerous for web-facing applications that accept image uploads. The vulnerability can be classified under ATT&CK technique T1203, which describes exploitation of remote services, and represents a common attack pattern where file format vulnerabilities are leveraged to achieve remote code execution.
Mitigation strategies for CVE-2016-3990 involve immediate patching of affected LibTIFF installations to versions 4.0.7 or later where the buffer overflow has been addressed through proper bounds checking and input validation. Organizations should prioritize updating their LibTIFF libraries across all systems that process TIFF images, particularly those with web-facing applications or systems that accept file uploads from untrusted users. Additionally, implementing proper input validation and sanitization measures can provide defense-in-depth protection, ensuring that TIFF files are validated before processing and that appropriate file size limits are enforced. Network segmentation and access controls should be implemented to limit exposure of vulnerable applications, while regular security assessments should be conducted to identify other potential vulnerabilities in image processing pipelines. The fix implemented by the LibTIFF maintainers included enhanced bounds checking within the horizontalDifference8 function and improved validation of pixel data sizes to prevent the buffer overflow condition from occurring. System administrators should also consider implementing automated monitoring for suspicious file processing activities and ensure that applications are running with minimal required privileges to limit potential damage from successful exploitation attempts.