CVE-2019-12415 in Financial Services Revenue Management and Billing
Summary
by MITRE
In Apache POI up to 4.1.0, when using the tool XSSFExportToXml to convert user-provided Microsoft Excel documents, a specially crafted document can allow an attacker to read files from the local filesystem or from internal network resources via XML External Entity (XXE) Processing.
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Analysis
by VulDB Data Team • 08/18/2025
Apache POI is a popular java library for processing Microsoft Office documents including excel files through various formats such as xls and xlsx. The vulnerability CVE-2019-12415 specifically affects the XSSFExportToXml functionality within Apache POI versions up to 4.1.0. This flaw arises from insufficient input validation and improper handling of external entity references during the conversion process of excel documents to xml format. When a user-provided excel file is processed through this export function, the system fails to properly sanitize xml entities that may be embedded within the document structure. This weakness allows an attacker to craft malicious excel files containing specially designed xml external entity declarations that reference local filesystem paths or internal network resources. The vulnerability stems from the library's failure to disable external entity resolution during xml parsing operations, creating an XXE processing attack surface where arbitrary file content can be accessed and exfiltrated from the system. According to CWE-611, this represents an improper restriction of XML external entity reference vulnerability that enables information disclosure and potential system compromise. The attack vector leverages the ATT&CK technique T1074.001 which involves data staging through external remote services, allowing adversaries to harvest sensitive data from local resources. The operational impact of this vulnerability is significant as it can lead to unauthorized access to confidential files, database credentials, system configuration details, and other sensitive information stored on the local filesystem or accessible via internal network services. An attacker could potentially access critical system files, user data, or corporate information by simply convincing a victim to open a malicious excel file through a vulnerable application that utilizes the affected Apache POI functionality. Organizations using Apache POI for processing user-uploaded excel documents are particularly at risk since the vulnerability can be exploited through simple file uploads without requiring additional privileges or complex attack chains. The mitigation strategy involves upgrading to Apache POI version 4.1.1 or later where the XXE vulnerability has been addressed through proper input sanitization and external entity disabling mechanisms. Additionally, administrators should implement strict input validation policies, disable unnecessary xml processing features, and consider using application-level firewalls or network segmentation to limit potential lateral movement if exploitation occurs. Security teams should also monitor for suspicious file upload activities and implement proper access controls to prevent unauthorized file processing operations that could leverage this vulnerability.