CVE-2017-11478 in ImageMagick
Summary
by MITRE
The ReadOneDJVUImage function in coders/djvu.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 and CPU consumption) via a malformed DJVU image.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-11478 represents a critical denial of service flaw within ImageMagick's handling of DJVU image files. This issue affects versions through 6.9.9-0 and 7.x through 7.0.6-1, making it a widespread concern for systems that process DJVU documents. The vulnerability resides in the ReadOneDJVUImage function located in coders/djvu.c, which fails to properly validate malformed DJVU image structures during the reading process. The flaw enables remote attackers to craft specially crafted DJVU files that trigger an infinite loop in the image processing routine, resulting in excessive cpu consumption that can effectively crash or render systems unavailable.
The technical nature of this vulnerability stems from insufficient input validation and error handling within the DJVU image parsing code. When ImageMagick encounters a malformed DJVU file, the ReadOneDJVUImage function enters a state where it repeatedly processes certain data structures without proper termination conditions. This behavior aligns with CWE-835, which describes the weakness of an infinite loop or infinite recursion, and represents a classic example of how malformed input can lead to resource exhaustion attacks. The vulnerability operates at the application level where ImageMagick processes image files, making it particularly dangerous for web applications and services that accept user-uploaded content.
From an operational standpoint, this vulnerability poses significant risks to systems that rely on ImageMagick for image processing tasks. Attackers can exploit this flaw by uploading or providing access to maliciously crafted DJVU files, which then causes the target system to consume excessive cpu resources. The infinite loop consumes system resources continuously until the process is manually terminated or the system becomes unresponsive. This type of attack falls under the ATT&CK technique T1499.004 for network denial of service, where adversaries leverage software vulnerabilities to exhaust system resources. The impact extends beyond simple service disruption to potentially affecting other applications running on the same system due to resource contention.
Systems most vulnerable include web applications, content management systems, and any platform that processes user-uploaded images using ImageMagick. The remote nature of the attack means that exploitation does not require local access, making it particularly dangerous for public-facing services. Organizations using ImageMagick for image processing workflows should prioritize patching this vulnerability as it represents a straightforward path to system instability. The recommended mitigation strategy involves upgrading to patched versions of ImageMagick where the input validation has been strengthened and proper loop termination conditions have been implemented. Additionally, implementing proper input sanitization at the application level and using file type validation before processing can provide defense in depth against similar vulnerabilities.