CVE-2019-18853 in ImageMagick
Summary
by MITRE
ImageMagick before 7.0.9-0 allows remote attackers to cause a denial of service because XML_PARSE_HUGE is not properly restricted in coders/svg.c, related to SVG and libxml2.
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Analysis
by VulDB Data Team • 02/11/2024
The vulnerability identified as CVE-2019-18853 affects ImageMagick versions prior to 7.0.9-0 and represents a significant denial of service weakness that can be exploited remotely by attackers. This flaw specifically resides within the handling of Scalable Vector Graphics files through the coders/svg.c component, where the XML_PARSE_HUGE flag is not adequately restricted. The vulnerability stems from improper configuration of libxml2 parsing behavior, which allows maliciously crafted SVG files to trigger excessive memory consumption and processing overhead.
The technical flaw manifests when ImageMagick processes SVG files that contain malformed or specially constructed XML content. The XML_PARSE_HUGE flag, when improperly enabled, permits libxml2 to parse XML documents with extremely large values, potentially leading to memory exhaustion and system instability. This occurs because the parser does not enforce appropriate limits on document size, entity expansion, or recursive parsing depth. Attackers can exploit this by submitting carefully crafted SVG files that contain malicious XML structures designed to trigger resource exhaustion during parsing operations.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect any system running vulnerable versions of ImageMagick that process user-uploaded SVG content. This includes web applications, content management systems, and file processing services that utilize ImageMagick for image conversion and manipulation. The denial of service can be achieved with relatively simple payloads, making it particularly dangerous for systems that do not implement proper input validation or resource limiting. The vulnerability can be exploited through various attack vectors including web uploads, file processing pipelines, and automated image conversion services.
From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses unchecked resource consumption, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the T1499 category for network denial of service. The flaw represents a classic example of insufficient input validation and resource management in XML processing libraries. Organizations should implement immediate mitigations including updating to ImageMagick version 7.0.9-0 or later, configuring appropriate XML parsing limits, and implementing input validation measures to restrict SVG file processing. Additionally, deploying network monitoring solutions to detect unusual resource consumption patterns and establishing proper access controls around image processing services can help prevent exploitation of this vulnerability.