CVE-2018-11656 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.7-20 Q16 x86_64, a memory leak vulnerability was found in the function ReadDCMImage in coders/dcm.c, which allows attackers to cause a denial of service via a crafted DCM image file.
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Analysis
by VulDB Data Team • 09/13/2024
The vulnerability identified as CVE-2018-11656 represents a critical memory leak flaw within ImageMagick's DICOM image processing functionality. This issue specifically affects version 7.0.7-20 of the software and manifests in the ReadDCMImage function located within the coders/dcm.c source file. The vulnerability arises when processing specially crafted DICOM image files that exploit improper memory management during the decoding process, leading to uncontrolled memory consumption that can ultimately result in system resource exhaustion.
The technical nature of this vulnerability stems from insufficient memory deallocation mechanisms within the DICOM image parser. When ImageMagick encounters a malformed or maliciously constructed DCM file, the ReadDCMImage function fails to properly release allocated memory blocks, causing progressive memory leakage with each processed file. This memory consumption pattern is particularly dangerous in server environments where ImageMagick might process multiple images sequentially, as the cumulative effect can rapidly deplete available system resources. The vulnerability operates at the application layer and can be triggered through any interface that utilizes ImageMagick's DICOM processing capabilities, including web applications, batch processing systems, and automated workflows.
From an operational impact perspective, this vulnerability creates significant risks for organizations relying on ImageMagick for image processing tasks. The memory leak can lead to system instability, application crashes, and complete denial of service conditions that prevent legitimate users from accessing services. Attackers can exploit this weakness by simply uploading or submitting a crafted DCM file to any system that processes DICOM images through ImageMagick, making it particularly dangerous in environments where user-uploaded content is processed without proper validation. The vulnerability is especially concerning in healthcare environments where DICOM files are routinely processed, as it could be used to disrupt critical medical imaging systems and potentially compromise patient care delivery.
Organizations should implement immediate mitigations including upgrading to ImageMagick version 7.0.7-21 or later, which contains the necessary patches to address the memory leak issue. Additionally, deploying input validation mechanisms that scan DICOM files for malformed structures before processing can provide an additional layer of protection. System administrators should also implement resource monitoring and limiting measures to detect and prevent memory exhaustion attacks. The vulnerability aligns with CWE-401, which specifically addresses improper management of memory allocation and deallocation, and can be categorized under ATT&CK technique T1499.3 for resource exhaustion attacks. Organizations should also consider implementing sandboxing mechanisms and restricting ImageMagick's capabilities to prevent unauthorized file processing, particularly in web-facing applications where the attack surface is maximized.