CVE-2017-18220 in GraphicsMagick
Summary
by MITRE
The ReadOneJNGImage and ReadJNGImage functions in coders/png.c in GraphicsMagick 1.3.26 allow remote attackers to cause a denial of service (magick/blob.c CloseBlob use-after-free) or possibly have unspecified other impact via a crafted file, a related issue to CVE-2017-11403.
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-18220 affects GraphicsMagick version 1.3.26 and resides within the png.c coder module where the ReadOneJNGImage and ReadJNGImage functions process JPEG Network Graphics files. This flaw represents a critical security issue that can be exploited remotely by attackers who craft malicious JNG files designed to trigger specific memory management errors during image processing operations. The vulnerability stems from improper handling of memory resources when processing these particular image formats, creating conditions that allow for use-after-free scenarios that can result in system instability or arbitrary code execution depending on the environment and exploitation method.
The technical implementation of this vulnerability involves memory management errors within the magick/blob.c component where the CloseBlob function is called after memory has already been freed, creating a use-after-free condition that can be leveraged by attackers to execute malicious code or cause system crashes. The flaw occurs specifically when GraphicsMagick processes crafted JNG files that contain malformed data structures which cause the application to attempt to access memory that has already been deallocated. This type of vulnerability falls under the CWE-416 category of Use After Free, which is classified as a critical weakness in memory management and represents a common vector for remote code execution attacks. The vulnerability is related to CVE-2017-11403 which indicates a pattern of similar memory handling issues within the GraphicsMagick codebase that affect multiple image processing functions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it can potentially enable remote code execution depending on the target system configuration and memory layout. When exploited, the use-after-free condition can cause the GraphicsMagick application to crash or behave unpredictably, but more concerning is the potential for attackers to manipulate the freed memory to execute arbitrary code with the privileges of the running process. This makes the vulnerability particularly dangerous in environments where GraphicsMagick is used to process untrusted image files such as web applications, email attachments, or file upload systems. The attack surface is broad given that many web applications and services rely on GraphicsMagick for image processing, making this vulnerability a significant risk for organizations that do not properly sandbox or restrict image processing operations.
Mitigation strategies for CVE-2017-18220 should prioritize immediate patching of affected GraphicsMagick installations to version 1.3.27 or later where the memory management issues have been addressed through proper resource handling and null pointer checks. Organizations should implement defensive measures such as input validation and file type verification to prevent processing of untrusted image files, along with sandboxing of image processing operations to limit the potential impact of exploitation. Network-level defenses including content filtering and web application firewalls can help detect and block malicious image files before they reach vulnerable systems. Additionally, security monitoring should be implemented to detect unusual behavior patterns that might indicate exploitation attempts, and regular security assessments should be conducted to identify similar vulnerabilities in other image processing libraries and components within the system architecture. The ATT&CK framework categorizes this vulnerability under T1203 - Exploitation for Client Execution and T1059 - Command and Scripting Interpreter, highlighting the potential for attackers to leverage this weakness to establish persistent access through compromised image processing services.