CVE-2017-12691 in ImageMagick
Summary
by MITRE
The ReadOneLayer function in coders/xcf.c in ImageMagick 7.0.6-6 allows remote attackers to cause a denial of service (memory consumption) via a crafted file.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-12691 represents a critical memory consumption issue within ImageMagick's XCF coder implementation. This flaw exists in the ReadOneLayer function located in coders/xcf.c of ImageMagick version 7.0.6-6, where attackers can exploit a specially crafted file to trigger excessive memory usage. The vulnerability falls under the category of denial of service attacks, specifically targeting memory consumption patterns that can lead to system instability or complete resource exhaustion. The XCF format is used for storing images in the GIMP image editing software, making this vulnerability particularly concerning for systems that process or convert GIMP image files. The flaw demonstrates a classic buffer over-read or improper memory management issue where the application fails to properly validate or limit memory allocation during the parsing of malformed XCF files, potentially allowing malicious actors to consume system resources at an exponential rate.
The technical exploitation of this vulnerability occurs when ImageMagick attempts to parse a maliciously crafted XCF file through the ReadOneLayer function. During this process, the application does not adequately validate the structure or size parameters of the input file, leading to uncontrolled memory allocation. The flaw can be classified as a CWE-129 issue, representing an insufficient input validation problem that allows for memory consumption attacks. Attackers can craft XCF files with malformed layer structures or excessive nesting that cause the application to allocate increasingly large amounts of memory without proper bounds checking. This type of vulnerability is particularly dangerous in web environments where ImageMagick is often used for image processing, as it can be exploited through file uploads or direct processing of user-supplied content, making it a prime target for remote exploitation. The attack vector operates through the standard ImageMagick processing pipeline, where the vulnerable function is called during file format parsing, creating a memory consumption spiral that can exhaust system resources.
The operational impact of CVE-2017-12691 extends beyond simple denial of service, as it can severely disrupt system availability and performance across various deployment environments. When exploited, this vulnerability can cause applications using ImageMagick to consume all available memory, leading to system crashes, application hangs, or complete system instability. The vulnerability is particularly concerning in multi-tenant environments such as web hosting platforms, content management systems, or cloud services that rely on ImageMagick for image processing, as a single malicious file can compromise entire systems or services. The attack can be executed remotely without authentication requirements, making it accessible to any attacker who can submit or process a crafted XCF file. This vulnerability aligns with ATT&CK technique T1499.003, which covers resource exhaustion attacks, and demonstrates how improper input handling can be leveraged to create system-wide availability issues. The impact is exacerbated in environments where ImageMagick is used as a backend service for image processing, as the memory consumption can affect other applications running on the same system.
Mitigation strategies for CVE-2017-12691 should focus on both immediate patching and operational security measures. The most effective solution involves upgrading to ImageMagick version 7.0.6-7 or later, which contains the necessary fixes to properly validate XCF file structures and limit memory allocation during parsing. Organizations should implement strict input validation and file type checking before processing any image files, particularly those from untrusted sources. Network-level protections such as file format filtering and size limitations can help prevent malicious files from reaching the ImageMagick processing layer. Security teams should also consider implementing memory monitoring and alerting systems to detect unusual memory consumption patterns that may indicate exploitation attempts. Additionally, containerization and resource limiting techniques can help contain the impact of such vulnerabilities by isolating ImageMagick processes and setting hard limits on memory usage. The vulnerability highlights the importance of proper input validation and memory management practices, aligning with security best practices outlined in the OWASP Top Ten and other industry standards for secure coding practices. Organizations should also implement regular security assessments and penetration testing to identify similar vulnerabilities in their image processing pipelines and ensure that all dependencies are kept current with security patches.