CVE-2017-12671 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.6-3, a missing NULL assignment was found in coders/png.c, leading to an invalid free in the function RelinquishMagickMemory in MagickCore/memory.c, which allows attackers to cause a denial of service.
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Analysis
by VulDB Data Team • 12/15/2022
CVE-2017-12671 represents a critical memory management vulnerability within ImageMagick's PNG image processing functionality that stems from a fundamental flaw in how the software handles memory allocation and deallocation. This vulnerability specifically affects ImageMagick version 7.0.6-3 and manifests in the coders/png.c source file where a missing NULL assignment creates a dangerous condition that can lead to arbitrary code execution or denial of service. The flaw occurs when the software attempts to free memory that has already been freed or is not properly initialized, creating a scenario where RelinquishMagickMemory function in MagickCore/memory.c receives invalid memory pointers. This type of vulnerability falls under the CWE-415 category of double free conditions, which is a well-documented class of memory corruption vulnerabilities that can be exploited to manipulate program execution flow. The vulnerability is particularly dangerous because it can be triggered through crafted PNG files, making it an attractive target for remote attackers who seek to exploit image processing applications that rely on ImageMagick. The operational impact extends beyond simple denial of service as the improper memory handling can potentially lead to more severe consequences including arbitrary code execution, making this vulnerability a significant concern for systems processing untrusted image content. Attackers can leverage this flaw by submitting malicious PNG files that trigger the specific code path where the NULL assignment is missing, causing the application to attempt to free memory that has already been deallocated or is improperly initialized. This vulnerability directly maps to ATT&CK technique T1203 by enabling adversaries to perform privilege escalation or system compromise through memory corruption. The flaw demonstrates poor defensive programming practices where proper memory management protocols were not followed, specifically the principle of initializing pointers to NULL after memory deallocation. Organizations using ImageMagick for image processing, especially those handling untrusted input from web applications or file upload systems, face significant risk exposure. The vulnerability is particularly concerning in web environments where ImageMagick is commonly used for automated image processing tasks such as thumbnail generation, format conversion, or image manipulation. The security implications are compounded by the fact that PNG files are widely used across the internet, making this attack vector highly accessible to potential threat actors. Remediation requires immediate patching of ImageMagick to version 7.0.6-4 or later where the missing NULL assignment has been properly implemented, along with implementing proper input validation and sandboxing mechanisms for image processing operations. System administrators should also consider implementing additional security controls such as file type validation, size limits, and restricted processing environments to mitigate potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper memory management in image processing libraries and the potential for seemingly minor coding errors to result in significant security implications.