CVE-2021-40146 in Any23
Summary
by MITRE • 09/11/2021
A Remote Code Execution (RCE) vulnerability was discovered in the Any23 YAMLExtractor.java file and is known to affect Any23 versions < 2.5. RCE vulnerabilities allow a malicious actor to execute any code of their choice on a remote machine over LAN, WAN, or internet. RCE belongs to the broader class of arbitrary code execution (ACE) vulnerabilities.
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Analysis
by VulDB Data Team • 09/16/2021
The CVE-2021-40146 vulnerability represents a critical remote code execution flaw within the Apache Any23 metadata extraction framework, specifically within the YAMLExtractor.java component. This vulnerability affects all versions prior to 2.5 and exposes systems to severe security risks where attackers can remotely execute arbitrary code on affected systems. The Any23 framework is designed for extracting structured metadata from various web documents including HTML, RDF, and other formats, making it a widely used component in semantic web applications and data processing pipelines. The vulnerability stems from improper input validation and handling within the YAML parsing functionality, creating a dangerous attack surface that can be exploited over network connections without requiring authentication or prior access to the system.
The technical implementation of this vulnerability resides in the YAMLExtractor.java file where insufficient sanitization of user-supplied input allows malicious YAML content to be processed and executed as code. When the framework encounters specially crafted YAML data, the parsing mechanism fails to properly validate or escape input parameters, enabling attackers to inject malicious code that gets executed within the context of the Any23 process. This flaw operates at the core of the framework's data processing pipeline, where YAML documents are parsed and converted into structured metadata, providing attackers with a direct pathway to execute commands on the target system. The vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and represents a classic example of arbitrary code execution through insecure deserialization or parsing mechanisms.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Any23 for data processing and metadata extraction services. Attackers can leverage this weakness to gain full control over affected systems, potentially leading to data breaches, system compromise, or lateral movement within network environments. The remote nature of the exploit means that attackers can target vulnerable systems from anywhere on the internet, making this vulnerability particularly dangerous for publicly exposed services. The impact extends beyond immediate system compromise as attackers can use this entry point to establish persistent access, deploy additional malware, or use the compromised system as a launchpad for attacks against other network resources. Organizations using Any23 in production environments face potential exposure to advanced persistent threats and zero-day exploitation attempts.
Mitigation strategies for CVE-2021-40146 primarily focus on immediate version upgrades to Any23 2.5 or later, which contain the necessary patches to address the YAML parsing vulnerability. System administrators should also implement network segmentation and access controls to limit exposure of Any23 services to trusted networks only. Additional protective measures include monitoring network traffic for suspicious YAML parsing patterns, implementing web application firewalls to detect and block malicious input, and conducting thorough vulnerability assessments of systems that utilize Any23 components. The remediation process should also include reviewing and updating security policies to ensure proper input validation and sanitization practices are implemented across all data processing components. Organizations should also consider implementing runtime application self-protection mechanisms and regular security testing to identify similar vulnerabilities in other framework components. This vulnerability demonstrates the importance of maintaining up-to-date security practices and the critical need for proper input validation in all data processing systems, aligning with ATT&CK technique T1059 which covers execution through command and scripting interpreters.