CVE-2018-10196 in Graphviz
Summary
by MITRE
NULL pointer dereference vulnerability in the rebuild_vlists function in lib/dotgen/conc.c in the dotgen library in Graphviz 2.40.1 allows remote attackers to cause a denial of service (application crash) via a crafted file.
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Analysis
by VulDB Data Team • 03/17/2023
The vulnerability identified as CVE-2018-10196 represents a critical null pointer dereference flaw within the dotgen library component of Graphviz version 2.40.1. This issue specifically manifests within the rebuild_vlists function located in the lib/dotgen/conc.c source file, creating a significant security risk that can be exploited remotely. The flaw occurs when the application processes malformed input files, leading to an application crash that constitutes a denial of service condition. Graphviz, being a widely-used graph visualization software, is frequently employed in various environments including web applications, development tools, and automated processing systems where its vulnerability can have widespread operational implications.
The technical nature of this vulnerability stems from improper input validation within the rebuild_vlists function which fails to adequately check for null pointer conditions before attempting to dereference memory addresses. When a specially crafted file is processed by the dotgen library, the function encounters a scenario where a pointer variable remains uninitialized or explicitly set to null, yet the code proceeds to access memory through this null reference. This classic null pointer dereference pattern falls under the CWE-476 weakness category, specifically representing a null pointer dereference vulnerability that directly leads to application instability and potential system crashes. The vulnerability is particularly concerning because it can be triggered through file-based input processing, making it exploitable via remote attack vectors where adversaries can upload or provide malicious files to systems running vulnerable Graphviz implementations.
The operational impact of CVE-2018-10196 extends beyond simple denial of service as it can disrupt critical graph processing workflows and automated systems that depend on Graphviz functionality. In web applications that utilize Graphviz for rendering diagrams, this vulnerability could allow attackers to crash services and potentially disrupt user access to graph visualization features. The vulnerability's remote exploitability means that systems processing untrusted graph files from external sources are at risk, including web servers, automated documentation generators, and collaborative platforms that integrate graph visualization capabilities. From an attack perspective, this flaw aligns with the ATT&CK technique T1499.004 which covers network denial of service attacks, and T1203 which involves exploitation of software vulnerabilities for system disruption. The impact is particularly severe in environments where Graphviz is used as part of automated processing pipelines, as a single malicious file could cause cascading failures across multiple dependent systems.
Mitigation strategies for this vulnerability require immediate patching of affected Graphviz installations to version 2.40.2 or later where the null pointer dereference has been addressed. Organizations should implement input validation and sanitization measures when processing graph files, particularly in web applications where user-uploaded content is processed through Graphviz libraries. The implementation of proper error handling and defensive programming practices within applications that utilize Graphviz components can help prevent exploitation of this and similar vulnerabilities. Additionally, network segmentation and access controls should be implemented to limit exposure of systems that process graph files, while regular security assessments should verify that all Graphviz installations are updated to secure versions. Security monitoring should be enhanced to detect unusual application crash patterns or denial of service conditions that could indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date software libraries and implementing automated patch management processes to prevent similar issues from compromising system availability and operational integrity.