CVE-2018-14065 in PHPOffice Common
Summary
by MITRE
XMLReader.php in PHPOffice Common before 0.2.9 allows XXE.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-14065 resides within the XMLReader.php component of PHPOffice Common library versions prior to 0.2.9, representing a critical server-side request forgery vulnerability that enables unauthorized external entity processing. This flaw specifically affects applications that utilize the PHPOffice library for handling XML documents, creating a pathway for malicious actors to exploit the system through XML external entity injection attacks. The vulnerability stems from insufficient input validation and sanitization within the XML parsing mechanism, allowing attackers to manipulate XML documents and potentially execute arbitrary code or access sensitive system resources.
The technical implementation of this vulnerability occurs when the XMLReader.php component processes untrusted XML input without proper restrictions on external entity resolution. Attackers can craft malicious XML payloads that reference external resources or leverage internal system files, enabling them to perform data exfiltration, denial of service attacks, or even achieve remote code execution depending on the system configuration. The flaw operates at the XML parsing layer where external entity declarations are not properly restricted, allowing the parser to resolve and process external references that could include malicious payloads or sensitive system information. This vulnerability directly maps to CWE-611, which categorizes insecure direct object references and improper restriction of XML external entities, and aligns with ATT&CK technique T1213.002 for data from information repositories, particularly when the attack involves extracting sensitive data through XML external entity manipulation.
The operational impact of CVE-2018-14065 extends beyond simple data exposure, as it can enable attackers to perform reconnaissance activities within the target environment and potentially escalate privileges. Systems utilizing vulnerable versions of PHPOffice Common may experience unauthorized access to internal network resources, file system enumeration, and potential privilege escalation depending on the execution context. The vulnerability is particularly dangerous in web applications that process user-uploaded XML files or accept XML data from external sources, as it can be exploited through various attack vectors including file upload restrictions bypass, API endpoints processing XML content, or web services consuming XML data from untrusted sources. Organizations running applications that depend on vulnerable PHPOffice Common versions face significant risk of data breaches, system compromise, and potential regulatory compliance violations.
Mitigation strategies for CVE-2018-14065 primarily involve immediate patching of the PHPOffice Common library to version 0.2.9 or later, which includes proper XML external entity restriction mechanisms. Security teams should implement comprehensive input validation for all XML processing components, disable external entity resolution in XML parsers, and employ strict XML schema validation to prevent malicious payloads from being processed. Additionally, organizations should conduct thorough vulnerability assessments to identify all applications utilizing vulnerable versions of the library, implement network segmentation to limit potential attack impact, and establish monitoring procedures to detect suspicious XML processing activities. The remediation approach should also include reviewing and updating XML parsing configurations to ensure that external entity resolution is disabled by default, aligning with security best practices outlined in industry standards such as OWASP XML Security Guidelines and NIST SP 800-53 security controls for input validation and data protection.