CVE-2015-8897 in ImageMagick
Summary
by MITRE
The SpliceImage function in MagickCore/transform.c in ImageMagick before 6.9.2-4 allows remote attackers to cause a denial of service (application crash) via a crafted png file.
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Analysis
by VulDB Data Team • 09/08/2020
The vulnerability identified as CVE-2015-8897 represents a critical denial of service flaw within ImageMagick's image processing library, specifically affecting the SpliceImage function located in MagickCore/transform.c. This vulnerability manifests when the software processes specially crafted png image files, creating a scenario where remote attackers can deliberately trigger application crashes without requiring any authentication or privileged access. The flaw exists in versions of ImageMagick prior to 6.9.2-4, making a substantial portion of the software ecosystem potentially vulnerable to this type of attack.
The technical mechanism behind this vulnerability involves improper input validation and memory handling within the SpliceImage function. When ImageMagick encounters a maliciously constructed png file, the function fails to properly validate the image data structure, leading to memory corruption or invalid memory access patterns that ultimately result in application termination. This type of vulnerability falls under the category of buffer overflows or memory corruption issues, which are commonly classified as CWE-121 for buffer overflow conditions or CWE-787 for out-of-bounds write operations. The vulnerability demonstrates a classic weakness in input sanitization where the software does not adequately validate the boundaries of image data before processing it.
From an operational perspective, this vulnerability poses significant risks to systems that rely on ImageMagick for image processing tasks, particularly web applications that accept user-uploaded images. Attackers can exploit this vulnerability by uploading or providing access to a specially crafted png file, which when processed by ImageMagick triggers the denial of service condition. This attack vector is particularly dangerous because it requires minimal privileges and can be executed remotely, making it an attractive target for attackers seeking to disrupt services. The impact extends beyond simple service disruption as it can be used in conjunction with other attacks to create more complex exploitation scenarios or to overwhelm system resources through repeated attacks.
The mitigation strategies for CVE-2015-8897 primarily involve upgrading to ImageMagick version 6.9.2-4 or later, which contains the necessary patches to address the memory handling issues in the SpliceImage function. Organizations should also implement additional defensive measures such as input validation and sanitization at multiple layers of their application architecture, including implementing file type verification before processing images and limiting the size and complexity of images that can be processed. Network-level protections such as web application firewalls can help detect and block malicious image uploads, while monitoring systems should be configured to alert on unusual patterns of image processing requests that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1499.001 for network denial of service attacks and demonstrates the importance of maintaining up-to-date software libraries to prevent exploitation of known vulnerabilities.