CVE-2020-27765 in ImageMagick
Summary
by MITRE • 12/04/2020
A flaw was found in ImageMagick in MagickCore/segment.c. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of math division by zero. This would most likely lead to an impact to application availability, but could potentially cause other problems related to undefined behavior. This flaw affects ImageMagick versions prior to 7.0.9-0.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/12/2020
The vulnerability identified as CVE-2020-27765 represents a critical division by zero error within ImageMagick's MagickCore library, specifically in the segment.c file responsible for image processing operations. This flaw exists in the core image manipulation functionality that processes various file formats and performs segmentation tasks on digital images. The issue manifests when ImageMagick encounters specially crafted input files that contain malformed data structures or invalid parameters during the segmentation process, leading to arithmetic exceptions that can crash applications using the library.
The technical exploitation of this vulnerability occurs through the manipulation of image processing parameters that result in mathematical operations attempting to divide by zero during the segmentation algorithm execution. When an attacker submits a crafted file that triggers this condition, the application experiences undefined behavior that typically manifests as application crashes or termination. The underlying cause stems from insufficient input validation and error handling within the segmentation routine, where the code does not properly check for zero values before performing division operations. This type of vulnerability falls under CWE-369, which specifically addresses the division by zero weakness in software systems, and represents a classic example of how improper input validation can lead to availability disruptions.
The operational impact of CVE-2020-27765 extends beyond simple application crashes to potentially compromise system availability and stability in environments where ImageMagick is extensively used for image processing tasks. Applications that rely on ImageMagick for automated image handling, web services processing user uploads, or content management systems could experience denial of service conditions when processing maliciously crafted files. The vulnerability affects all ImageMagick versions prior to 7.0.9-0, making it particularly concerning for organizations running older installations that may not have received timely security updates. This flaw can be exploited in various attack scenarios including web application exploitation, automated scanning systems, or any environment where untrusted image files are processed through ImageMagick libraries.
Organizations should prioritize immediate remediation by upgrading to ImageMagick version 7.0.9-0 or later, which contains the necessary patches to address the division by zero condition in the segmentation component. Additionally, implementing proper input validation and sanitization measures can provide defense-in-depth protection against similar vulnerabilities. System administrators should also consider implementing file type validation, size limits, and sandboxing techniques when processing user-uploaded images to minimize the potential impact of such vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under T1203, which covers exploitation of remote services, and T1499, which addresses network denial of service attacks, highlighting the importance of addressing these weaknesses in security architectures. Regular security assessments and vulnerability scanning should include checks for outdated ImageMagick installations to prevent exploitation of this and similar historical vulnerabilities.