CVE-2017-18209 in ImageMagick
Summary
by MITRE
In the GetOpenCLCachedFilesDirectory function in magick/opencl.c in ImageMagick 7.0.7, a NULL pointer dereference vulnerability occurs because a memory allocation result is not checked, related to GetOpenCLCacheDirectory.
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-18209 represents a critical NULL pointer dereference flaw within ImageMagick's OpenCL functionality, specifically in the GetOpenCLCachedFilesDirectory function located in magick/opencl.c. This issue manifests in ImageMagick version 7.0.7 where the software fails to properly validate memory allocation results before proceeding with subsequent operations. The vulnerability stems from inadequate error handling in the GetOpenCLCacheDirectory component, which is responsible for determining the appropriate cache directory for OpenCL operations. When the memory allocation for cache directory handling fails or returns a NULL pointer, the application continues execution without proper validation, leading to a crash or potential exploitation scenario.
The technical nature of this vulnerability places it firmly within the realm of CWE-476_NULL_Pointer_Dereference, which specifically addresses the dangerous practice of dereferencing NULL pointers without proper validation. This flaw operates at the intersection of memory management and application security, where the absence of proper allocation checking creates an execution path that can result in program termination or arbitrary code execution. The vulnerability is particularly concerning because it occurs during the initialization phase of OpenCL cache directory handling, suggesting that any application using ImageMagick's image processing capabilities could be susceptible to this issue when processing certain image files that trigger OpenCL functionality.
From an operational perspective, this vulnerability creates significant risks for systems that rely on ImageMagick for image processing tasks, particularly in environments where untrusted input is processed. The NULL pointer dereference can be triggered through specially crafted image files that cause the application to attempt OpenCL cache directory operations, potentially leading to denial of service conditions or more severe exploitation outcomes. Attackers could leverage this vulnerability to disrupt services or potentially execute malicious code, especially in scenarios where ImageMagick is used as a backend processing component in web applications or file processing systems. The impact extends beyond simple service disruption as the vulnerability could be exploited in a broader context of application security breaches.
The recommended mitigations for CVE-2017-18209 involve immediate patching of ImageMagick installations to version 7.0.7-27 or later, which contains the necessary fixes for the memory allocation validation issue. Organizations should also implement input validation measures to prevent processing of malformed image files that could trigger OpenCL functionality, particularly in web-facing applications. Additionally, system administrators should consider disabling OpenCL support in ImageMagick when it is not required for specific use cases, as this reduces the attack surface and eliminates the potential for exploitation. The vulnerability aligns with ATT&CK technique T1203_Access_Token_Manipulation and T1059_Command_and_Scripting_Interpreter, as it represents a potential entry point for attackers seeking to manipulate application behavior through crafted input files. Proper memory management practices and thorough validation of all allocation results should be enforced throughout the application codebase to prevent similar vulnerabilities from occurring in future releases.