CVE-2018-20184 in GraphicsMagick
Summary
by MITRE
In GraphicsMagick 1.4 snapshot-20181209 Q8, there is a heap-based buffer overflow in the WriteTGAImage function of tga.c, which allows attackers to cause a denial of service via a crafted image file, because the number of rows or columns can exceed the pixel-dimension restrictions of the TGA specification.
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Analysis
by VulDB Data Team • 06/19/2023
The vulnerability identified as CVE-2018-20184 represents a critical heap-based buffer overflow flaw within GraphicsMagick version 1.4 snapshot-20181209 Q8, specifically affecting the WriteTGAImage function located in the tga.c source file. This vulnerability stems from inadequate input validation and boundary checking mechanisms when processing Tagged Image File Format TGA image files. The flaw occurs when the software fails to properly validate the dimensional parameters of TGA images, allowing maliciously crafted image files to specify row or column counts that exceed the legitimate pixel-dimension restrictions defined by the TGA specification. This oversight creates a scenario where the application attempts to allocate memory based on invalid dimensions, leading to memory corruption that manifests as a buffer overflow condition.
The technical exploitation of this vulnerability involves attackers creating specially crafted TGA image files with malformed dimensional parameters that cause the WriteTGAImage function to attempt memory allocations beyond the intended buffer boundaries. When GraphicsMagick processes these malicious files, the function does not properly validate whether the specified number of rows or columns falls within the acceptable limits defined by the TGA format specification, which typically restricts image dimensions to prevent excessive memory consumption. The buffer overflow occurs during the image writing process when the software attempts to write pixel data to memory locations that are either unallocated or insufficiently sized to accommodate the specified dimensions, resulting in memory corruption that can lead to application crashes or unpredictable behavior.
The operational impact of CVE-2018-20184 extends beyond simple denial of service conditions, as it represents a potential vector for more sophisticated attacks within systems that rely on GraphicsMagick for image processing operations. When exploited, this vulnerability can cause applications using GraphicsMagick to crash or become unresponsive, effectively rendering the software unavailable for legitimate image processing tasks. The vulnerability is particularly concerning in environments where GraphicsMagick is used as part of automated image processing pipelines, content management systems, or web applications that accept user-uploaded images, as attackers could leverage this flaw to disrupt services or potentially escalate their attack to achieve arbitrary code execution. The heap-based nature of the overflow also means that memory corruption could potentially be exploited to manipulate program execution flow, making this vulnerability a significant concern for system security.
Mitigation strategies for CVE-2018-20184 should prioritize immediate patching of affected GraphicsMagick installations to the latest stable versions that contain proper input validation and boundary checking mechanisms. System administrators should implement strict file validation processes that verify image file integrity before processing, particularly for user-uploaded content in web applications. The implementation of sandboxing techniques and memory protection mechanisms can help contain potential exploitation attempts, while regular security audits of image processing pipelines should be conducted to identify and remediate similar vulnerabilities. Additionally, organizations should consider implementing automated monitoring for unusual memory allocation patterns or process crashes that could indicate exploitation attempts. This vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a potential entry point for ATT&CK technique T1059.007 for command and control communications through compromised image processing systems. Regular updates and security assessments of third-party libraries and image processing components remain essential practices to prevent similar vulnerabilities from compromising system integrity.