CVE-2017-11537 in ImageMagick
Summary
by MITRE
When ImageMagick 7.0.6-1 processes a crafted file in convert, it can lead to a Floating Point Exception (FPE) in the WritePALMImage() function in coders/palm.c, related to an incorrect bits-per-pixel calculation.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-11537 represents a critical floating point exception flaw within ImageMagick version 7.0.6-1, specifically affecting the convert utility when processing maliciously crafted input files. This issue manifests in the WritePALMImage() function located within the coders/palm.c source file, demonstrating how improper handling of image data can lead to system instability and potential exploitation. The flaw arises from an incorrect bits-per-pixel calculation that causes the application to encounter a floating point exception during image processing operations, creating a denial of service condition that could be leveraged by malicious actors to disrupt system operations.
The technical implementation of this vulnerability stems from a mathematical error in the PALM image format writer component of ImageMagick, where the calculation of bits-per-pixel values fails to properly validate input data before performing arithmetic operations. This type of error falls under the CWE-369 vulnerability category, which specifically addresses the division by zero or floating point exception conditions that can occur when processing malformed input data. The improper bits-per-pixel calculation creates a scenario where the floating point unit encounters an invalid operation during the image writing process, causing the application to terminate abnormally. This particular implementation demonstrates how seemingly innocuous format handling code can become a vector for system disruption when proper input validation is omitted.
From an operational perspective, this vulnerability presents significant risks to systems that process untrusted image files through ImageMagick, particularly in web applications, content management systems, and file upload interfaces. The floating point exception can be triggered through crafted PALM image files that contain malformed header data or incorrect bit depth specifications, allowing attackers to cause convert utility processes to crash or behave unpredictably. The impact extends beyond simple denial of service as this vulnerability could potentially be chained with other exploits to achieve more sophisticated attack vectors, particularly in environments where ImageMagick is used as part of automated processing pipelines or in server-side image manipulation workflows.
The exploitation of CVE-2017-11537 aligns with ATT&CK technique T1203, which involves using malicious files to cause system instability through resource exhaustion or process termination. Security professionals should consider this vulnerability in the context of broader attack surface management, particularly in environments where automated image processing is performed on user-uploaded content. The vulnerability's classification as a floating point exception also relates to broader security considerations around signal handling and process termination in image processing libraries, making it relevant to defense-in-depth strategies that include input sanitization, process isolation, and proper error handling mechanisms. Organizations should implement immediate mitigations including version updates to ImageMagick 7.0.6-2 or later, which contain the necessary patches to address the incorrect bits-per-pixel calculation logic and prevent the floating point exception from occurring during image processing operations.
This vulnerability exemplifies the importance of proper input validation and error handling in multimedia processing libraries, where malformed data can lead to unexpected system behavior. The fix implemented by ImageMagick developers involved correcting the bits-per-pixel calculation to properly validate input parameters before performing arithmetic operations, preventing the division by zero or invalid floating point operations that previously caused system crashes. The remediation approach demonstrates how addressing fundamental mathematical errors in image format processing can prevent both denial of service conditions and potential privilege escalation scenarios that might otherwise be possible in poorly validated multimedia libraries.