CVE-2018-17966 in ImageMagick
Summary
by MITRE
ImageMagick 7.0.7-28 has a memory leak vulnerability in WritePDBImage in coders/pdb.c.
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Analysis
by VulDB Data Team • 05/22/2023
The vulnerability identified as CVE-2018-17966 represents a critical memory leak flaw within ImageMagick version 7.0.7-28, specifically affecting the WritePDBImage function located in the coders/pdb.c source file. This memory leak occurs during the processing of PDB (Program Database) image format files, which are commonly used in Microsoft development environments for storing debugging information. The flaw manifests when ImageMagick attempts to write PDB format images, leading to improper memory management where allocated memory blocks are not correctly freed, resulting in gradual memory consumption over time.
The technical implementation of this vulnerability stems from inadequate memory deallocation practices within the PDB writing component of ImageMagick's coder library. When processing certain PDB files, the WritePDBImage function fails to properly release dynamically allocated memory resources, creating a condition where each subsequent PDB image processing operation consumes additional memory without corresponding cleanup. This memory leak behavior can be exploited through malicious PDB files or by repeatedly processing PDB images, leading to progressive memory exhaustion on systems running vulnerable ImageMagick versions. The vulnerability operates at the application level and can be triggered through various attack vectors including web applications that utilize ImageMagick for image processing, file upload handlers, or automated image conversion workflows.
The operational impact of this memory leak vulnerability extends beyond simple resource consumption, potentially leading to system instability, denial of service conditions, and performance degradation across affected platforms. Systems utilizing ImageMagick for image processing tasks, particularly those handling high volumes of file conversions or operating in resource-constrained environments, face increased risk of memory exhaustion attacks. The vulnerability is particularly concerning in web server environments where ImageMagick is commonly integrated into content management systems, e-commerce platforms, or any application that accepts user-uploaded image files. Attackers could exploit this weakness by submitting crafted PDB files that trigger the memory leak during processing, potentially causing service disruption or system crashes.
Mitigation strategies for CVE-2018-17966 require immediate patching of ImageMagick installations to versions that address the memory leak in the PDB coder implementation. System administrators should prioritize updating to ImageMagick 7.0.8-1 or later releases which contain the necessary fixes for this vulnerability. Additionally, implementing proper input validation and sanitization measures can reduce exposure by preventing malicious PDB files from reaching the vulnerable processing functions. Network-level controls such as file type restrictions, upload size limits, and content scanning can provide additional defensive layers. Organizations should also consider implementing monitoring solutions to detect unusual memory consumption patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-401, which catalogs improper cleanup of memory allocation, and represents a typical example of how memory management flaws in image processing libraries can create persistent security risks. From an ATT&CK framework perspective, this vulnerability could be leveraged during the resource exhaustion phase of an attack, potentially supporting broader exploitation campaigns targeting system availability.