CVE-2017-9501 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.5-7 Q16, an assertion failure was found in the function LockSemaphoreInfo, which allows attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-9501 represents a critical assertion failure within ImageMagick's threading synchronization mechanisms, specifically within the LockSemaphoreInfo function of the software's Q16 implementation. This flaw exists in ImageMagick version 7.0.5-7 and demonstrates how improper handling of semaphore locking can lead to system instability and denial of service conditions. The issue manifests when the software processes crafted malicious files that trigger an assertion failure, causing the application to terminate unexpectedly and potentially disrupting legitimate user operations.
The technical nature of this vulnerability stems from inadequate input validation and error handling within ImageMagick's internal threading infrastructure. When a maliciously crafted file is processed, the LockSemaphoreInfo function fails to properly manage the semaphore state, leading to an assertion failure that terminates the application process. This represents a classic denial of service vulnerability where an attacker can exploit the software's failure to handle malformed input gracefully. The flaw operates at the core level of ImageMagick's concurrency management system, making it particularly dangerous as it can affect any application or system that relies on ImageMagick for image processing operations.
From an operational impact perspective, this vulnerability creates significant security concerns for organizations that depend on ImageMagick for image handling tasks. The denial of service condition can affect web applications, content management systems, and any platform that accepts user-uploaded images without proper validation. Attackers can exploit this vulnerability by uploading specially crafted image files that, when processed by ImageMagick, trigger the assertion failure and cause the target application to crash or become unresponsive. This vulnerability aligns with CWE-617, which categorizes assertion failures that can be triggered by external input as a path to denial of service conditions. The impact extends beyond simple service disruption as it can potentially be leveraged in larger attack chains where service availability is a critical component of the overall compromise strategy.
Organizations should implement immediate mitigations including updating to patched versions of ImageMagick where available, implementing strict input validation for all image uploads, and deploying web application firewalls to filter potentially malicious file types. The vulnerability demonstrates the importance of proper error handling in multi-threaded applications and highlights the need for robust input sanitization practices. Security teams should also consider implementing monitoring for unusual application termination patterns and ensure that image processing services are properly isolated to limit the impact of potential exploitation. This vulnerability serves as a reminder of the critical importance of proper concurrency control mechanisms in security-sensitive applications and aligns with ATT&CK technique T1499.004 which covers the use of denial of service techniques to disrupt services. The flaw also emphasizes the necessity of comprehensive testing procedures including fuzzing to identify similar assertion failures in complex software systems that handle concurrent operations.