CVE-2017-14741 in ImageMagick
Summary
by MITRE
The ReadCAPTIONImage function in coders/caption.c in ImageMagick 7.0.7-3 allows remote attackers to cause a denial of service (infinite loop) via a crafted font file.
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Analysis
by VulDB Data Team • 08/19/2024
The vulnerability identified as CVE-2017-14741 resides within the ImageMagick image processing library, specifically in the ReadCAPTIONImage function located in the coders/caption.c file. This flaw represents a critical security issue that affects ImageMagick version 7.0.7-3 and potentially earlier versions. The vulnerability manifests as a denial of service condition that can be triggered remotely through the careful crafting of font files, allowing attackers to induce an infinite loop within the application's processing pipeline. The affected function processes caption images and handles font rendering operations, making it a prime target for exploitation in systems that process untrusted image content.
The technical root cause of this vulnerability stems from inadequate input validation and loop termination conditions within the font processing logic. When ImageMagick attempts to read and render caption images using malformed font files, the parsing routine fails to properly handle certain edge cases in font data structures, leading to infinite loops in the execution flow. This occurs because the font parsing algorithm does not adequately check for malformed data or implement proper bounds checking during the processing of font metrics and character positioning information. The flaw falls under the category of improper input validation and can be classified as CWE-835, which specifically addresses loops with insufficient loop condition termination. The vulnerability demonstrates a classic example of how insufficient validation of user-supplied data can lead to resource exhaustion and system instability.
The operational impact of CVE-2017-14741 extends beyond simple denial of service, as it can be leveraged in broader attack scenarios within the context of the MITRE ATT&CK framework's resource exhaustion tactics. Systems utilizing ImageMagick for image processing, including web applications, content management systems, and file upload services, become vulnerable to sustained denial of service attacks that can consume significant system resources. Attackers can craft malicious font files that, when processed by vulnerable ImageMagick installations, cause the application to enter infinite loops, consuming CPU cycles and potentially leading to system resource exhaustion. This vulnerability is particularly dangerous in environments where ImageMagick is used to process user-uploaded content, as it enables attackers to disrupt service availability without requiring authentication or complex exploitation techniques. The vulnerability can be exploited across various attack vectors including web applications, file processing services, and automated image conversion systems, making it a significant concern for organizations relying on ImageMagick for image handling operations.
Mitigation strategies for CVE-2017-14741 should focus on immediate patching of affected ImageMagick installations to version 7.0.7-4 or later, which contains the necessary fixes for the infinite loop condition. Organizations should implement comprehensive input validation and sanitization measures for all image processing workflows, particularly those involving user-uploaded content. Network-level defenses can include implementing rate limiting and resource quotas for image processing operations to prevent abuse. The vulnerability also highlights the importance of proper sandboxing and execution environment isolation for image processing tasks. Security teams should conduct thorough vulnerability assessments to identify all systems running vulnerable versions of ImageMagick and implement monitoring for potential exploitation attempts. Additionally, organizations should consider implementing automated patch management processes to ensure timely deployment of security updates and maintain up-to-date threat intelligence on similar vulnerabilities within the image processing ecosystem. The remediation approach should align with industry best practices for secure coding and input validation as outlined in various cybersecurity frameworks including those from NIST and ISO/IEC 27001.