CVE-2014-3529 in POI
Summary
by MITRE
The OPC SAX setup in Apache POI before 3.10.1 allows remote attackers to read arbitrary files via an OpenXML file containing an XML external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
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Analysis
by VulDB Data Team • 03/28/2022
The vulnerability identified as CVE-2014-3529 represents a critical XML External Entity (XXE) flaw within Apache POI's OPC SAX setup component. This issue affects versions prior to 3.10.1 and stems from insufficient input validation when processing OpenXML files. The vulnerability enables remote attackers to exploit the system by crafting malicious OpenXML documents containing XML external entity declarations that reference local files on the target system. When the vulnerable Apache POI library processes these crafted files, it fails to properly sanitize external entity references, allowing unauthorized file access through XML parsing mechanisms. The flaw specifically impacts the Simple API for XML (SAX) parser implementation within the Open Packaging Conventions (OPC) framework that Apache POI uses to handle Office document formats.
The technical exploitation of this vulnerability occurs through the manipulation of XML entities within OpenXML documents, leveraging the XML parsing capabilities of Apache POI's OPC SAX setup. Attackers can construct malicious files that contain entity declarations referencing system files such as /etc/passwd on Unix systems or Windows system files. When the vulnerable library processes these documents, it automatically resolves the entity references, effectively reading the contents of arbitrary files on the server where the application is running. This process bypasses normal file access controls and can lead to information disclosure of sensitive data, system configuration files, and potentially credentials stored in accessible locations. The vulnerability is classified as CWE-611 according to the Common Weakness Enumeration, which specifically addresses Improper Restriction of XML External Entity Reference.
The operational impact of CVE-2014-3529 extends beyond simple information disclosure, as it can enable attackers to perform reconnaissance activities and potentially escalate privileges within affected systems. Organizations using Apache POI libraries for processing Office documents, including those in enterprise environments, web applications, and document management systems, face significant risk. The vulnerability is particularly dangerous in environments where documents are processed without proper input sanitization, such as web applications accepting file uploads or automated document processing systems. Attackers can use this vulnerability to extract sensitive information from system files, potentially gaining insights into system configurations, user accounts, and application data that could facilitate further attacks. The impact is amplified when the affected applications run with elevated privileges, as the file reading capabilities could extend to sensitive system resources.
Mitigation strategies for CVE-2014-3529 primarily focus on updating Apache POI to version 3.10.1 or later, which includes proper XML external entity validation and sanitization. Organizations should implement comprehensive patch management processes to ensure all affected systems receive the security updates promptly. Additional protective measures include implementing strict input validation for all OpenXML documents processed by applications, disabling external entity resolution in XML parsers, and configuring security policies that restrict file access permissions. Security professionals should also consider deploying XML parsing restrictions at the application level and implementing network segmentation to limit the potential impact of successful exploitation. The vulnerability demonstrates the importance of secure coding practices and proper input validation, particularly when handling untrusted XML content. Organizations should review their document processing workflows and ensure that all third-party libraries are kept current with security patches, as this vulnerability represents a classic example of how XML parsing flaws can lead to serious security consequences. The ATT&CK framework categorizes this vulnerability under the technique of "Exploitation for Credential Access" when used to extract system credentials from configuration files, making it a significant concern for enterprise security posture.