CVE-2017-13140 in ImageMagick
Summary
by MITRE
In ImageMagick before 6.9.9-1 and 7.x before 7.0.6-2, the ReadOnePNGImage function in coders/png.c allows remote attackers to cause a denial of service (application hang in LockSemaphoreInfo) via a PNG file with a width equal to MAGICK_WIDTH_LIMIT.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2017-13140 represents a critical denial of service flaw within ImageMagick's PNG image processing functionality. This issue affects versions prior to 6.9.9-1 and 7.x prior to 7.0.6-2, where the ReadOnePNGImage function in the coders/png.c file demonstrates a specific weakness that can be exploited by remote attackers to cause application hang conditions. The flaw manifests when processing specially crafted PNG files that have a width parameter set exactly equal to MAGICK_WIDTH_LIMIT, a configuration value that serves as a boundary check for image dimensions within the ImageMagick library.
The technical implementation of this vulnerability stems from inadequate input validation within the PNG parsing routine. When ImageMagick encounters a PNG file with a width value matching the MAGICK_WIDTH_LIMIT constant, the processing logic enters an infinite loop or extended waiting state within the LockSemaphoreInfo function. This semaphore locking mechanism, designed to prevent concurrent access issues during image processing, becomes a point of failure when the width parameter triggers specific conditional branches in the code that lead to deadlock scenarios. The vulnerability specifically exploits the boundary condition where the width parameter equals the predefined limit, causing the application to hang indefinitely while attempting to acquire or release semaphore locks.
From an operational perspective, this vulnerability poses significant risks to systems that process untrusted image files, particularly web applications, content management systems, and file upload services that rely on ImageMagick for image handling. Attackers can leverage this flaw by uploading or providing malicious PNG files with dimensions matching the MAGICK_WIDTH_LIMIT, thereby causing legitimate applications using ImageMagick to become unresponsive. The impact extends beyond simple service disruption as the hanging application consumes system resources and may lead to cascading failures in web servers or application stacks that depend on timely image processing. This vulnerability can be particularly dangerous in high-traffic environments where multiple concurrent requests could be simultaneously affected, leading to complete service degradation.
The mitigation strategies for CVE-2017-13140 primarily involve upgrading to patched versions of ImageMagick where the ReadOnePNGImage function has been modified to properly handle boundary conditions and prevent the semaphore locking deadlock. Organizations should implement immediate version updates to ImageMagick 6.9.9-1 or 7.0.6-2, or newer releases that contain the necessary code modifications. Additionally, administrators should consider implementing input validation measures at the application level, including setting stricter limits on image dimensions and implementing timeout mechanisms for image processing operations. The vulnerability aligns with CWE-400, which addresses unrestricted resource consumption, and can be categorized under ATT&CK technique T1499.001 for network denial of service attacks. Security teams should also consider implementing file type validation and size restrictions as additional defensive measures to prevent exploitation of similar boundary condition vulnerabilities in other image processing libraries.