CVE-2022-0239 in corenlp
Summary
by MITRE • 01/17/2022
corenlp is vulnerable to Improper Restriction of XML External Entity Reference
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2022-0239 affects the corenlp library and represents a critical improper restriction of XML external entity reference flaw that enables attackers to exploit XML parsing functionality. This vulnerability resides within the corenlp processing pipeline where XML documents are parsed and processed, creating potential attack vectors through maliciously crafted XML inputs that can trigger unauthorized resource access or denial of service conditions. The flaw specifically manifests when the library processes XML content without adequate safeguards against external entity resolution, allowing adversaries to manipulate the parsing behavior through carefully constructed XML documents containing external entity declarations.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of XML input streams within the corenlp framework. When the system encounters XML data containing external entity references, it fails to properly restrict or disable the resolution of these entities, thereby enabling attackers to reference external resources or execute malicious payloads through XML external entity expansion. This vulnerability aligns with CWE-611 which specifically addresses improper restriction of XML external entity reference, and operates under the broader category of XML injection attacks that have been consistently identified as critical threats in web application security. The flaw essentially allows an attacker to perform server-side request forgery attacks by leveraging the XML parser's capability to resolve external entities, potentially leading to information disclosure, denial of service, or even remote code execution depending on the underlying system configuration.
The operational impact of CVE-2022-0239 extends beyond simple denial of service conditions to encompass potential data breaches and system compromise scenarios. An attacker exploiting this vulnerability can gain unauthorized access to internal network resources, extract sensitive information from the system, or cause cascading failures through resource exhaustion attacks. The vulnerability affects any application utilizing corenlp for processing XML content, particularly those handling untrusted input from users or external sources. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1213.002 which involves data from external removable media, and T1499.004 which covers unauthorized data access through server-side request forgery. The attack surface is particularly broad given that corenlp is commonly used in natural language processing applications, machine learning pipelines, and enterprise content management systems where XML processing is prevalent.
Mitigation strategies for CVE-2022-0239 require immediate implementation of XML parser configuration changes to disable external entity resolution and DTD processing. Organizations should implement strict input validation and sanitization measures that filter out or properly escape XML special characters before processing. The recommended approach includes configuring XML parsers with secure defaults that disable external entity resolution, restrict access to local files, and implement proper resource limits to prevent denial of service conditions. Additionally, network segmentation and firewall rules should be implemented to limit access to systems processing XML content, while regular security audits should verify that XML processing components are properly configured. Security patches should be applied immediately to all affected systems, and application developers should conduct thorough code reviews to ensure that XML processing functions properly validate and sanitize all input data before processing. The remediation process should also include implementing monitoring and logging mechanisms to detect potential exploitation attempts and establish incident response procedures for rapid containment of any successful attacks.