CVE-2018-7470 in ImageMagick
Summary
by MITRE
An issue was discovered in ImageMagick 7.0.7-22 Q16. The IsWEBPImageLossless function in coders/webp.c allows attackers to cause a denial of service (segmentation violation) via a crafted file.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7470 represents a critical denial of service flaw within ImageMagick's webp image processing library. This issue affects version 7.0.7-22 Q16 and stems from improper handling of malformed webp image files during the lossless image detection process. The vulnerability manifests when the IsWEBPImageLossless function in coders/webp.c encounters crafted input that triggers a segmentation fault, causing the application to crash and terminate unexpectedly. This flaw exists at the intersection of image format parsing and memory management, creating a scenario where maliciously constructed webp files can disrupt normal application operation.
The technical root cause of this vulnerability lies in insufficient input validation and memory boundary checking within the webp decoder implementation. When ImageMagick processes a webp file, the IsWEBPImageLossless function attempts to determine whether the image can be decoded using lossless compression methods. However, the function fails to properly validate the structure and content of the webp container format, particularly when dealing with malformed or specially crafted data. This inadequate validation leads to memory access violations when the function attempts to read or write beyond allocated memory boundaries, resulting in segmentation faults that crash the application process. The vulnerability operates at the level of buffer over-read conditions and improper memory dereferencing, which are commonly classified under CWE-125 and CWE-787 respectively.
The operational impact of CVE-2018-7470 extends beyond simple application crashes, creating significant security implications for systems that process untrusted image files. Attackers can leverage this vulnerability to perform denial of service attacks against web applications, content management systems, or any service that utilizes ImageMagick for image processing. The vulnerability is particularly concerning in environments where automated image processing occurs, such as social media platforms, e-commerce sites, or document management systems, where attackers could flood systems with malicious webp files to exhaust resources or cause service disruptions. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service and can be exploited as part of broader attack chains targeting application availability.
Mitigation strategies for this vulnerability require immediate patching of ImageMagick installations to versions that address the memory handling issues in the webp coder. System administrators should prioritize updating their ImageMagick deployments to versions released after the vulnerability disclosure, typically 7.0.8-0 or later, which contain proper input validation and memory boundary checks. Additionally, implementing input sanitization measures such as file type validation, size limits, and content scanning can provide defense in depth. Organizations should also consider restricting image processing capabilities for untrusted inputs, implementing proper error handling to prevent crash propagation, and deploying monitoring systems to detect unusual application termination patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of robust input validation in multimedia processing libraries and highlights the need for comprehensive memory safety practices in image format parsers.