CVE-2017-18211 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.7, a NULL pointer dereference vulnerability was found in the function saveBinaryCLProgram in magick/opencl.c because a program-lookup result is not checked, related to CacheOpenCLKernel.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-18211 represents a critical NULL pointer dereference flaw within ImageMagick version 7.0.7, specifically within the opencl.c source file at the saveBinaryCLProgram function. This issue arises from insufficient validation of program-lookup results during CacheOpenCLKernel operations, creating a scenario where the application attempts to dereference a null pointer reference. The flaw demonstrates a classic software security weakness that can lead to application crashes or potentially more severe consequences depending on the execution context. According to CWE-476, this vulnerability maps directly to the Null Pointer Dereference weakness category, where a pointer expected to reference a valid memory location instead contains a null value, leading to program termination or unpredictable behavior. The vulnerability manifests when ImageMagick processes certain image files that trigger the OpenCL kernel caching mechanism, particularly when the system attempts to save binary OpenCL programs during image processing operations.
The technical exploitation of this vulnerability occurs when an attacker crafts or manipulates image files that contain specific OpenCL-related metadata or structures that cause the saveBinaryCLProgram function to execute with an unchecked program lookup result. The function fails to validate whether the program lookup operation successfully returned a valid program object before proceeding with operations that assume the program pointer is valid. This flaw can be leveraged through a denial of service attack where the application crashes when encountering malformed input files, as the null pointer dereference causes an immediate program termination. The operational impact extends beyond simple crashes since this vulnerability could potentially be chained with other exploits or used as a stepping stone in more complex attack scenarios targeting systems that rely on ImageMagick for image processing. The vulnerability affects systems where ImageMagick is used to process untrusted image content, particularly in web applications, file processing services, or automated image analysis systems that do not properly validate input files before processing.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or cause system instability. The vulnerability is particularly concerning in environments where ImageMagick is used as a backend processing component for user-uploaded content, as it provides an attack surface that can be exploited to cause service disruption or potentially gain further system access. The lack of proper input validation and error checking in the OpenCL kernel handling code represents a fundamental security gap that could be exploited by attackers to cause system instability or denial of service conditions. Organizations using ImageMagick in production environments should consider the potential for this vulnerability to be used in automated attack scenarios where multiple malformed files are processed in sequence to maximize impact. The vulnerability's classification as a NULL pointer dereference makes it relatively straightforward to exploit, requiring only that an attacker provide input that triggers the specific code path within the OpenCL processing functionality. Remediation efforts should focus on implementing proper validation of program lookup results and ensuring that all pointer operations are checked before dereferencing, which aligns with security best practices outlined in the OWASP Top Ten and other industry security frameworks. The vulnerability highlights the importance of thorough input validation and error handling in security-critical code paths, particularly in multimedia processing libraries that handle untrusted input from diverse sources.