CVE-2018-16644 in ImageMagick
Summary
by MITRE
There is a missing check for length in the functions ReadDCMImage of coders/dcm.c and ReadPICTImage of coders/pict.c in ImageMagick 7.0.8-11, which allows remote attackers to cause a denial of service via a crafted image.
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Analysis
by VulDB Data Team • 05/07/2023
The vulnerability identified as CVE-2018-16644 represents a critical denial of service weakness within ImageMagick's image processing libraries, specifically affecting versions up to 7.0.8-11. This issue stems from insufficient input validation in two distinct image parsing functions that handle different file formats. The flaw manifests in the ReadDCMImage function within coders/dcm.c which processes DICOM medical imaging files, and the ReadPICTImage function in coders/pict.c responsible for handling PICT format images. Both functions fail to properly validate the length of data structures during parsing operations, creating opportunities for malformed input to trigger unexpected behavior in the application's memory management.
The technical implementation of this vulnerability exploits the absence of proper bounds checking mechanisms when processing image metadata and data structures. When ImageMagick attempts to parse a crafted DICOM or PICT file, the missing length validation allows attackers to provide malformed data that causes the application to allocate memory or process data structures without proper size constraints. This condition typically leads to memory corruption scenarios where the application may attempt to access memory locations beyond allocated buffers or process invalid data lengths, ultimately resulting in application crashes or complete system denial of service.
From an operational perspective, this vulnerability presents significant risks for systems that process untrusted image files, particularly web applications, content management systems, and file processing services that utilize ImageMagick for image handling. Remote attackers can exploit this weakness by crafting specially formatted DICOM or PICT files that, when processed by vulnerable ImageMagick installations, will cause the application to consume excessive resources or crash entirely. The impact extends beyond simple service disruption as this vulnerability can be leveraged in automated attack scenarios where multiple malicious files are processed in rapid succession, potentially exhausting system resources or causing cascading failures in applications that depend on ImageMagick for image processing tasks.
The vulnerability aligns with CWE-129, which describes improper validation of length of input buffers, and represents a classic example of insufficient input validation that can lead to memory safety issues. From an attack framework perspective, this weakness maps to the MITRE ATT&CK technique T1499.001 for Network Denial of Service, where attackers specifically target application vulnerabilities to cause service disruption. The attack surface is particularly broad given that ImageMagick is widely deployed across various platforms and applications, making this vulnerability particularly dangerous as it can be exploited across multiple attack vectors including web uploads, email attachments, and file sharing systems. Organizations using ImageMagick in production environments should prioritize immediate patching of affected versions to prevent exploitation of this denial of service vulnerability.
Mitigation strategies for CVE-2018-16644 should focus on immediate version updates to ImageMagick 7.0.8-12 or later releases where the missing length validation has been addressed. System administrators should also implement additional defensive measures including restricting file upload capabilities, implementing strict file type validation, and deploying sandboxed processing environments for untrusted image files. Network-based protections such as intrusion detection systems can be configured to monitor for patterns associated with malicious image file processing attempts. Additionally, organizations should consider implementing automated patch management processes to ensure timely deployment of security updates across all systems utilizing ImageMagick components. The vulnerability demonstrates the critical importance of input validation in image processing libraries and serves as a reminder of the potential impact that seemingly minor validation gaps can have on system availability and security posture.