CVE-2017-12431 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.6-1, a use-after-free vulnerability was found in the function ReadWMFImage in coders/wmf.c, which allows attackers to cause a denial of service.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-12431 represents a critical use-after-free flaw within ImageMagick's WMF image processing functionality. This issue manifests in the ReadWMFImage function located within the coders/wmf.c source file, where improper memory management allows attackers to manipulate the application's memory state through crafted WMF image files. The vulnerability specifically affects ImageMagick version 7.0.6-1, making it particularly concerning given the widespread use of this image processing library across various platforms and applications.
The technical nature of this flaw stems from a classic memory safety issue where freed memory locations are accessed after being deallocated, creating potential for arbitrary code execution or system instability. When ImageMagick processes a maliciously crafted WMF file, the ReadWMFImage function fails to properly manage memory references, leading to a situation where subsequent operations attempt to access memory that has already been freed. This memory corruption scenario can result in application crashes, heap corruption, or potentially more severe consequences depending on the execution environment and memory layout. The vulnerability operates at the level of memory management within the image parsing pipeline, specifically targeting the WMF (Windows Metafile) format handling component.
From an operational perspective, this vulnerability poses significant risks to systems that process untrusted image files, particularly web applications, content management systems, and any software that relies on ImageMagick for image handling. The denial of service impact can be leveraged by attackers to disrupt services, causing availability issues that may affect business operations. The vulnerability's exploitation potential extends beyond simple denial of service, as use-after-free conditions in image processing libraries can often be chained with other vulnerabilities to achieve more sophisticated attacks. Organizations using ImageMagick for processing user-uploaded content face particular risk, as a single malicious file can compromise entire systems. The ATT&CK framework categorizes this type of vulnerability under T1203 - Exploitation for Client Execution and T1499 - Endpoint Denial of Service, highlighting its potential for both service disruption and system compromise.
Mitigation strategies for CVE-2017-12431 should prioritize immediate patching of affected ImageMagick installations to version 7.0.6-2 or later, which contains the necessary memory management fixes. System administrators should implement strict file validation and sanitization protocols, particularly for user-uploaded content, and consider employing sandboxing techniques when processing untrusted images. Network-level controls can help by implementing content filtering that blocks potentially malicious image formats or by using automated scanning tools to identify vulnerable installations. Organizations should also consider implementing privilege separation where image processing occurs in restricted environments, limiting the potential impact of successful exploitation. The CWE database classifies this vulnerability as CWE-416: Use After Free, which emphasizes the importance of proper memory management practices and the need for thorough code reviews to prevent similar issues. Regular security assessments and vulnerability scanning should be implemented to identify other potential memory safety issues within the application stack, particularly in libraries that handle complex file format parsing operations.