CVE-2017-18254 in ImageMagick
Summary
by MITRE
An issue was discovered in ImageMagick 7.0.7. A memory leak vulnerability was found in the function WriteGIFImage in coders/gif.c, which allow remote attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2017-18254 represents a critical memory leak flaw within ImageMagick version 7.0.7, specifically affecting the WriteGIFImage function located in the coders/gif.c source file. This memory leak vulnerability constitutes a significant security risk that can be exploited by remote attackers to execute denial of service attacks against systems processing image files. The flaw arises from inadequate memory management within the GIF image writing functionality, where allocated memory resources are not properly released during the processing of maliciously crafted GIF files.
The technical implementation of this vulnerability stems from improper memory deallocation practices within the WriteGIFImage function, which processes GIF image files for output operations. When ImageMagick encounters a specially crafted GIF file, the function fails to correctly free previously allocated memory blocks, leading to progressive memory consumption over time. This memory leak occurs during the image encoding process when the software attempts to write GIF formatted data, creating a condition where memory resources accumulate without proper cleanup. The vulnerability manifests as a gradual increase in memory usage that can eventually exhaust available system resources, rendering the affected application or system unusable.
From an operational perspective, this vulnerability presents a substantial risk to organizations relying on ImageMagick for image processing tasks, particularly in web applications, content management systems, and file upload services. Attackers can exploit this flaw by uploading or submitting malicious GIF files that trigger the memory leak condition, potentially causing service disruption, application crashes, or complete system hangs. The remote exploitability of this vulnerability means that attackers do not need local access to the system, making it particularly dangerous in web-facing environments where users can submit arbitrary files. The impact extends beyond simple denial of service, as sustained exploitation can lead to system instability and resource exhaustion that affects other applications running on the same host.
The vulnerability aligns with CWE-401, which specifically addresses "Improper Release of Memory Before Removing Last Reference to Resource," and represents a classic example of memory management errors that can be exploited for denial of service attacks. From an adversarial perspective, this flaw fits within the ATT&CK technique T1499.004, which covers "Endpoint Denial of Service: OS File Execution," as it enables attackers to cause system resource exhaustion through crafted file processing. Organizations using ImageMagick in production environments should prioritize immediate patching of this vulnerability, as the memory leak can be exploited continuously to degrade system performance or cause complete service outages. The remediation strategy involves updating to ImageMagick version 7.0.8 or later, where the memory leak has been addressed through proper memory deallocation mechanisms in the affected function, ensuring that all allocated resources are correctly freed during GIF image processing operations.