CVE-2018-12544 in Vert.x
Summary
by MITRE
In version from 3.5.Beta1 to 3.5.3 of Eclipse Vert.x, the OpenAPI XML type validator creates XML parsers without taking appropriate defense against XML attacks. This mechanism is exclusively when the developer uses the Eclipse Vert.x OpenAPI XML type validator to validate a provided schema.
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Analysis
by VulDB Data Team • 05/25/2023
The vulnerability identified as CVE-2018-12544 resides within the Eclipse Vert.x framework version range from 3.5.Beta1 through 3.5.3, specifically affecting the OpenAPI XML type validator component. This flaw represents a critical security oversight that exposes applications using the framework to potential denial of service and arbitrary code execution attacks. The vulnerability stems from the validator's implementation of XML parser instantiation without adequate protection mechanisms against various XML-based attack vectors including XML external entity processing and XML bomb attacks. The security implications become particularly severe when developers integrate the OpenAPI XML type validator into their applications, as this creates an attack surface that adversaries can exploit to compromise system integrity and availability.
The technical root cause of this vulnerability aligns with CWE-611, which addresses improper access control in XML processing, and CWE-400, which covers resource exhaustion vulnerabilities in XML parsers. The flaw manifests when the OpenAPI XML validator creates XML parsers without implementing proper security configurations that would prevent malicious XML content from being processed. This includes the absence of restrictions on external entity resolution, DTD processing, and namespace prefix declarations that could enable attackers to craft specially malformed XML documents designed to consume excessive system resources or execute unauthorized operations. The validator's implementation fails to configure parsers with secure defaults that would mitigate common XML attack patterns such as the billion laughs attack, quadratic blowup attacks, and other resource exhaustion techniques that can overwhelm system memory and processing capabilities.
The operational impact of CVE-2018-12544 extends beyond simple denial of service scenarios to encompass potential data breaches and system compromise. Applications that utilize the affected Eclipse Vert.x versions and employ the OpenAPI XML validator become vulnerable to attackers who can craft malicious XML payloads to trigger resource exhaustion conditions that may lead to system crashes or allow for unauthorized code execution. This vulnerability particularly affects RESTful APIs and microservices architectures that rely on OpenAPI specifications for API documentation and validation, as these systems often process untrusted input from various sources. The attack surface becomes more pronounced in environments where the framework is used for API gateway implementations or service orchestration components that handle XML-based request validation, creating opportunities for attackers to exploit the vulnerability in production environments.
Organizations utilizing Eclipse Vert.x versions within the affected range should implement immediate mitigations to address this vulnerability. The primary recommendation involves upgrading to Eclipse Vert.x version 3.5.4 or later, which contains the necessary security patches and proper XML parser configuration. Additionally, developers should consider implementing application-level defenses such as input validation, XML parser hardening, and resource monitoring to detect and prevent exploitation attempts. Security teams should also implement network-level protections including firewalls and intrusion detection systems to monitor for suspicious XML processing patterns and potential exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in XML processing components and aligns with ATT&CK technique T1210 which covers exploitation of remote services through XML external entity processing attacks. Organizations should also conduct comprehensive security assessments of their API endpoints and service integrations to identify potential exposure points and ensure that all XML processing components are properly configured with security best practices including disabling external entity resolution, limiting document size, and implementing appropriate timeout mechanisms to prevent resource exhaustion attacks.