CVE-2020-27768 in ImageMagick
Summary
by MITRE • 02/23/2021
In ImageMagick, there is an outside the range of representable values of type 'unsigned int' at MagickCore/quantum-private.h. This flaw affects ImageMagick versions prior to 7.0.9-0.
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Analysis
by VulDB Data Team • 03/04/2021
The vulnerability identified as CVE-2020-27768 represents a critical integer overflow condition within ImageMagick's quantum processing subsystem. This flaw exists in the MagickCore/quantum-private.h file where operations involving unsigned int data types can exceed the maximum representable values allowed by the type, creating a scenario where arithmetic operations produce unexpected results due to wraparound behavior. The issue specifically impacts versions of ImageMagick prior to 7.0.9-0, making it a significant concern for systems running older implementations of this widely-used image processing library.
The technical nature of this vulnerability stems from improper handling of quantum values during image processing operations. Quantum represents the basic unit of color information in ImageMagick's internal processing pipeline, and when calculations exceed the bounds of unsigned int data type, the system experiences undefined behavior that can lead to memory corruption. This type of integer overflow vulnerability falls under the CWE-191 category of "Integer Underflow (Wrap or Wraparound)" and represents a classic example of how improper bounds checking can create exploitable conditions in image processing software. The vulnerability is particularly dangerous because it occurs during the fundamental quantum processing operations that are essential to image manipulation and conversion functions.
From an operational perspective, this vulnerability creates significant security risks for systems that process untrusted image files through ImageMagick. Attackers could potentially craft malicious image files that trigger the integer overflow during processing, leading to memory corruption that might be exploited to execute arbitrary code or cause denial of service conditions. The impact extends beyond simple exploitation scenarios as the vulnerability affects the core image processing capabilities, meaning any application relying on ImageMagick for image handling could be compromised. This aligns with ATT&CK technique T1203 which involves gaining access through manipulation of image files, and T1059 which covers execution through command-line interfaces where such vulnerabilities might be leveraged.
Mitigation strategies for CVE-2020-27768 primarily involve upgrading to ImageMagick version 7.0.9-0 or later, which contains the necessary patches to prevent the integer overflow condition. Organizations should conduct thorough inventory assessments to identify all systems running vulnerable versions of ImageMagick and implement immediate patching procedures. Additionally, implementing proper input validation and sanitization measures when processing image files can provide defense-in-depth protection. System administrators should consider deploying automated monitoring solutions to detect potential exploitation attempts and establish network segmentation to limit the potential impact of successful attacks. The vulnerability demonstrates the importance of maintaining up-to-date security patches in image processing libraries, as these components are frequently used in web applications, content management systems, and digital asset management platforms where they represent prime targets for attackers seeking to exploit image processing vulnerabilities.