CVE-2018-13794 in catimg
Summary
by MITRE
A heap-based buffer overflow exists in stbi__bmp_load_cont in stb_image.h in catimg 2.4.0.
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Analysis
by VulDB Data Team • 04/05/2023
The vulnerability CVE-2018-13794 represents a critical heap-based buffer overflow in the catimg image processing utility version 2.4.0. This flaw resides within the stbi__bmp_load_cont function of the stb_image.h library, which is a widely used single-header library for image loading in C and C++ applications. The issue manifests when processing malformed bmp image files that contain specially crafted data structures designed to trigger memory corruption during the loading process. The vulnerability is particularly concerning as it affects a library that is commonly integrated into various applications and systems, potentially creating widespread exploitation opportunities.
The technical implementation of this buffer overflow occurs due to inadequate input validation and memory boundary checking within the BMP image parsing logic. When catimg processes a maliciously crafted bmp file, the stbi__bmp_load_cont function fails to properly validate the dimensions and data structure of the image file before attempting to allocate heap memory for image data. This leads to a situation where the application attempts to write more data to a heap-allocated buffer than it was originally sized to accommodate, resulting in memory corruption that can be exploited by attackers. The vulnerability is classified as a heap-based buffer overflow, which falls under the CWE-121 category of buffer overflow conditions in heap-based data structures. This type of vulnerability is particularly dangerous because it can lead to arbitrary code execution when the corrupted memory is subsequently accessed by the application.
The operational impact of CVE-2018-13794 extends beyond simple denial of service scenarios, as it creates significant security risks for systems that process user-uploaded or untrusted image files. Attackers can leverage this vulnerability to execute arbitrary code on vulnerable systems with the privileges of the user running the catimg utility. The attack vector is straightforward requiring only that a user or application processes a maliciously crafted bmp image file through the catimg utility. This makes the vulnerability particularly dangerous in web applications, file processing services, or any environment where users can upload image files that will be processed by the affected software. The vulnerability can be mapped to ATT&CK technique T1203, which covers exploitation of software vulnerabilities through heap-based buffer overflows, and also aligns with T1059 for command and control through arbitrary code execution.
Mitigation strategies for CVE-2018-13794 should focus on immediate software updates and input validation improvements. The most effective remediation is upgrading to a patched version of catimg that addresses the buffer overflow in the stb_image.h library, which typically involves implementing proper bounds checking and input validation in the image parsing routines. Additionally, organizations should implement strict input validation for all image file processing, including size and format verification before any parsing occurs. Security measures should include sandboxing image processing operations, implementing memory protection mechanisms such as stack canaries and address space layout randomization, and conducting regular security audits of third-party libraries. The vulnerability also highlights the importance of maintaining up-to-date dependencies and implementing proper code review processes to identify similar issues in other parts of the codebase, particularly in memory management functions that handle untrusted data inputs.