CVE-2017-14103 in GraphicsMagick
Summary
by MITRE
The ReadJNGImage and ReadOneJNGImage functions in coders/png.c in GraphicsMagick 1.3.26 do not properly manage image pointers after certain error conditions, which allows remote attackers to conduct use-after-free attacks via a crafted file, related to a ReadMNGImage out-of-order CloseBlob call. NOTE: this vulnerability exists because of an incomplete fix for CVE-2017-11403.
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Analysis
by VulDB Data Team • 11/12/2019
The vulnerability identified as CVE-2017-14103 represents a critical use-after-free flaw in GraphicsMagick's handling of JNG (JPEG Network Graphics) image files. This issue specifically affects the ReadJNGImage and ReadOneJNGImage functions located within the coders/png.c source file of GraphicsMagick version 1.3.26. The flaw stems from improper management of image pointers following error conditions, creating a scenario where remote attackers can exploit this weakness through carefully crafted JNG files. The vulnerability is particularly dangerous because it enables attackers to execute arbitrary code on systems that process these image files, making it a significant concern for web applications and services that handle user-uploaded graphics content.
The technical root cause of this vulnerability lies in the improper cleanup and pointer management during error handling within the image processing pipeline. When GraphicsMagick encounters certain error conditions while parsing JNG files, the code fails to properly release or nullify image pointers before proceeding with subsequent operations. This creates a situation where freed memory locations may still be referenced, leading to use-after-free conditions that attackers can leverage for exploitation. The vulnerability is particularly insidious because it involves an out-of-order CloseBlob call that occurs during the ReadMNGImage process, disrupting the normal memory management sequence and creating opportunities for memory corruption. This issue is classified under CWE-416 as Use After Free, which is a well-known vulnerability pattern that has been extensively documented in the cybersecurity community and frequently targeted by attackers for privilege escalation and code execution.
The operational impact of CVE-2017-14103 extends beyond simple denial of service scenarios to encompass full remote code execution capabilities. Systems running GraphicsMagick 1.3.26 that process untrusted image files are at risk, particularly web applications, content management systems, and any service that accepts file uploads. The vulnerability can be exploited through various attack vectors including web-based file uploads, email attachments, and file sharing platforms where JNG images are processed. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, as it enables attackers to execute arbitrary code on vulnerable systems. The flaw's relationship to CVE-2017-11403 demonstrates the persistence of flawed memory management patterns and highlights the importance of thorough regression testing when implementing security patches, as incomplete fixes can leave systems vulnerable to similar exploitation techniques.
Mitigation strategies for CVE-2017-14103 require immediate action including upgrading to GraphicsMagick version 1.3.27 or later, which contains the complete fix for this vulnerability. Organizations should also implement defensive measures such as restricting file upload capabilities, implementing strict file type validation, and deploying sandboxed environments for image processing. Network-level defenses including intrusion detection systems and web application firewalls can help detect and prevent exploitation attempts. Additionally, regular security assessments and penetration testing should be conducted to identify similar memory management flaws in other image processing libraries and applications. The vulnerability serves as a reminder of the critical importance of proper memory management in security-critical code and the necessity of comprehensive testing for error handling paths. Security teams should also consider implementing automated monitoring for systems processing image files, as the exploitation of such vulnerabilities can occur without user interaction and may go undetected for extended periods, making continuous vigilance essential for maintaining system integrity.