CVE-2011-3194 in Digia
Summary
by MITRE
Buffer overflow in the TIFF reader in gui/image/qtiffhandler.cpp in Qt 4.7.4 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via the TIFFTAG_SAMPLESPERPIXEL tag in a greyscale TIFF image with multiple samples per pixel.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability described in CVE-2011-3194 represents a critical buffer overflow condition within the Qt framework's TIFF image handling component. This flaw exists in the qtiffhandler.cpp file of Qt version 4.7.4, specifically affecting the processing of TIFF image files with multiple samples per pixel. The vulnerability is classified as a buffer overflow under CWE-121, which occurs when a program writes data beyond the bounds of a fixed-length buffer, potentially leading to memory corruption and unpredictable behavior. The issue manifests when the application processes a greyscale TIFF image containing the TIFFTAG_SAMPLESPERPIXEL tag with multiple samples per pixel, creating a scenario where insufficient bounds checking allows malicious input to overwrite adjacent memory regions.
The technical exploitation of this vulnerability involves crafting a specially formatted TIFF image file that triggers the buffer overflow during the parsing of the TIFFTAG_SAMPLESPERPIXEL tag. When Qt's image processing library encounters this malformed input, it fails to properly validate the number of samples per pixel against the allocated buffer space, resulting in a memory overwrite condition. This memory corruption can manifest as an application crash or, in more sophisticated attack scenarios, potentially allow remote code execution. The vulnerability demonstrates characteristics consistent with CWE-787, which specifically addresses out-of-bounds write conditions that can lead to arbitrary code execution when attackers can control the overflowed data.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a potential entry point for more sophisticated attacks. Systems that process untrusted TIFF image files through Qt applications become vulnerable to remote exploitation, particularly in web applications, document processing systems, or any environment where users can upload or view TIFF images. The vulnerability affects a wide range of applications built on Qt 4.7.4, including desktop applications, web browsers, and server-side image processing systems. From an ATT&CK framework perspective, this vulnerability maps to T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as it enables adversaries to execute arbitrary code on vulnerable systems. The attack surface is particularly concerning given that TIFF is a widely used image format in professional and enterprise environments.
Organizations should implement immediate mitigations including upgrading to Qt versions that contain the patched TIFF handling code, typically Qt 4.8.0 or later. Additionally, input validation should be implemented at the application level to filter or reject TIFF files with suspicious sample per pixel configurations. Network-based mitigations can include implementing file type validation and content filtering to prevent malicious TIFF files from reaching vulnerable applications. The patch for this vulnerability addresses the specific buffer overflow by implementing proper bounds checking for the TIFFTAG_SAMPLESPERPIXEL tag processing, ensuring that the number of samples per pixel does not exceed the allocated buffer capacity. Security monitoring should focus on detecting unusual image processing patterns and potential exploitation attempts through malformed TIFF file uploads, as this vulnerability can be leveraged in web-based attacks targeting applications that utilize Qt's image handling capabilities.