CVE-2017-11523 in ImageMagick
Summary
by MITRE
The ReadTXTImage function in coders/txt.c in ImageMagick through 6.9.9-0 and 7.x through 7.0.6-1 allows remote attackers to cause a denial of service (infinite loop) via a crafted file, because the end-of-file condition is not considered.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-11523 represents a critical denial of service flaw within ImageMagick's text file processing capabilities. This issue affects versions up through 6.9.9-0 and 7.x through 7.0.6-1, where the ReadTXTImage function in the coders/txt.c module fails to properly handle end-of-file conditions during text file parsing operations. The flaw occurs when ImageMagick encounters a specially crafted text file that triggers an infinite loop in the processing logic, effectively consuming system resources and rendering the application unresponsive.
The technical root cause of this vulnerability stems from inadequate input validation and boundary condition checking within the text parsing routine. When the ReadTXTImage function processes a malformed text file, it fails to properly detect when the end of file has been reached, causing the parsing loop to continue indefinitely. This condition creates a classic denial of service scenario where legitimate system resources become consumed without proper termination conditions. The vulnerability is particularly dangerous because it can be triggered through remote file processing operations, making it exploitable over network connections without requiring local system access.
From an operational perspective, this vulnerability poses significant risks to systems that utilize ImageMagick for automated image processing tasks, particularly those handling user-uploaded content or remote file retrieval operations. Attackers can craft malicious text files that, when processed by vulnerable ImageMagick installations, will cause the application to enter an infinite loop, consuming CPU cycles and potentially leading to system resource exhaustion. This makes the vulnerability particularly dangerous in web applications, content management systems, and automated processing pipelines where ImageMagick is commonly deployed. The impact extends beyond simple service disruption to potentially enabling more sophisticated attacks through resource exhaustion techniques.
The vulnerability aligns with CWE-835, which specifically addresses the issue of infinite loops in software implementations, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations using ImageMagick in production environments should prioritize immediate patching to address this vulnerability, as the infinite loop condition can be exploited remotely to cause system instability. Mitigation strategies include implementing proper input validation, deploying rate limiting mechanisms, and ensuring that all ImageMagick installations are updated to versions that contain the fix for this specific parsing flaw. Additionally, system administrators should consider implementing monitoring solutions to detect unusual CPU usage patterns that may indicate exploitation attempts.