CVE-2017-6497 in ImageMagick
Summary
by MITRE
An issue was discovered in ImageMagick 6.9.7. A specially crafted psd file could lead to a NULL pointer dereference (thus, a DoS).
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Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2017-6497 resides within ImageMagick version 6.9.7, representing a critical denial of service weakness that stems from improper handling of specially crafted psd files. This flaw manifests as a NULL pointer dereference condition that occurs when the software attempts to process maliciously constructed photoshop document format files. The issue demonstrates the classic characteristics of a buffer over-read or null pointer access vulnerability, where the application fails to validate input parameters before attempting to access memory locations that may not be properly initialized or allocated.
The technical exploitation of this vulnerability occurs through the manipulation of psd file structures that contain malformed data within their metadata or layer information. When ImageMagick processes such files, the software's parser encounters unexpected data patterns that cause the program to attempt to dereference a NULL pointer, leading to an immediate crash of the application. This behavior aligns with CWE-476 which specifically addresses NULL pointer dereference vulnerabilities, and represents a fundamental flaw in input validation and error handling mechanisms within the image processing pipeline. The vulnerability exists in the image format handling code where the application does not properly check for valid pointers before attempting to access them, creating an execution path that terminates the process abruptly.
From an operational perspective, this vulnerability presents significant risks to systems that process user-uploaded images or handle automated image conversions, particularly in web applications, content management systems, and digital asset management platforms. The denial of service impact means that attackers can reliably crash ImageMagick processes by simply uploading a malicious psd file, potentially leading to service unavailability and system downtime. This vulnerability is particularly concerning in environments where ImageMagick is used as a backend service for image processing workflows, as it can be exploited to disrupt legitimate operations without requiring elevated privileges or complex attack vectors. The attack surface is broad since psd files are commonly used in professional graphic design and can be easily embedded in various web applications or uploaded through user interfaces.
Mitigation strategies for CVE-2017-6497 should focus on immediate patching of affected ImageMagick installations to version 6.9.8-0 or later, which contains the necessary fixes for the NULL pointer dereference issue. Organizations should implement comprehensive input validation measures that filter or reject potentially malicious image files before they reach the ImageMagick processing engine. Network-based mitigations can include implementing file type validation and content scanning to identify and block suspicious psd files. Additionally, system administrators should consider implementing application sandboxing or containerization techniques to limit the impact of potential exploitation. The vulnerability demonstrates the importance of proper error handling and defensive programming practices, aligning with ATT&CK technique T1499 which addresses disruption of services through denial of service attacks. Organizations should also establish monitoring protocols to detect unusual application crashes or service disruptions that may indicate exploitation attempts, as well as maintain regular vulnerability assessments to identify similar issues in other image processing libraries and applications.