CVE-2018-16641 in ImageMagick
Summary
by MITRE
ImageMagick 7.0.8-6 has a memory leak vulnerability in the TIFFWritePhotoshopLayers function in coders/tiff.c.
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Analysis
by VulDB Data Team • 05/07/2023
The vulnerability identified as CVE-2018-16641 represents a critical memory leak flaw within ImageMagick's TIFF file processing capabilities. This issue specifically affects version 7.0.8-6 of the popular image processing library, which is widely used across various platforms and applications for handling multiple image formats. The memory leak occurs within the TIFFWritePhotoshopLayers function located in the coders/tiff.c source file, indicating a fundamental weakness in how the software manages memory allocation during TIFF file creation with embedded Photoshop layers. Such vulnerabilities pose significant risks to systems that process untrusted image files, particularly in web applications and automated processing environments where attackers could exploit this weakness through crafted malicious TIFF files.
The technical nature of this vulnerability stems from improper memory management within the TIFF writing functionality when handling Photoshop layers data. When ImageMagick processes TIFF files containing Photoshop layers, the TIFFWritePhotoshopLayers function fails to properly release allocated memory resources after completing the writing operation. This memory leak manifests as progressive memory consumption that can eventually lead to system instability, application crashes, or complete system resource exhaustion. The flaw operates at the software level where memory allocation occurs without corresponding deallocation, creating a persistent memory footprint that grows with each processed file. This type of vulnerability is categorized under CWE-401 as "Improper Release of Memory Before Removing Last Reference" and aligns with ATT&CK technique T1499.001 for "Network Denial of Service" through resource exhaustion attacks.
The operational impact of CVE-2018-16641 extends beyond simple performance degradation to potentially enable more sophisticated attack vectors. Systems that rely on ImageMagick for automated image processing, including web servers, content management systems, and digital asset management platforms, become vulnerable to denial of service conditions. Attackers could exploit this vulnerability by uploading specially crafted TIFF files that trigger the memory leak during processing, gradually consuming system resources until the application becomes unresponsive or crashes. In high-traffic environments, this could result in complete service disruption, making it particularly dangerous for web applications that accept user-uploaded images. The vulnerability's exploitation potential increases when combined with other memory-related issues, as attackers might chain this leak with other techniques to amplify the impact.
Mitigation strategies for CVE-2018-16641 should focus on immediate remediation through version updates, as the vulnerability has been addressed in subsequent releases of ImageMagick. Organizations must prioritize patching their ImageMagick installations to versions that contain the memory management fixes for the TIFFWritePhotoshopLayers function. Additionally, implementing proper input validation and sanitization measures can help reduce the attack surface by limiting the types of TIFF files processed and monitoring for unusual memory consumption patterns. Network-level protections such as rate limiting and file type restrictions can prevent malicious file uploads from reaching vulnerable systems. System administrators should also establish monitoring protocols to detect abnormal memory usage patterns that might indicate exploitation attempts, while maintaining regular security assessments to identify similar memory management issues in other software components. The vulnerability demonstrates the critical importance of proper memory management in image processing libraries and the potential for seemingly minor flaws to create significant security risks in widely deployed software.