CVE-2018-20157 in OpenRefine
Summary
by MITRE
The data import functionality in OpenRefine through 3.1 allows an XML External Entity (XXE) attack through a crafted (zip) file, allowing attackers to read arbitrary files.
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Analysis
by VulDB Data Team • 06/19/2023
The vulnerability identified as CVE-2018-20157 represents a critical security flaw in OpenRefine version 3.1 and earlier, specifically within its data import functionality. This vulnerability arises from insufficient input validation and improper handling of XML entities during the processing of zip archives containing maliciously crafted XML content. The flaw enables attackers to exploit XML External Entity processing mechanisms, creating a pathway for unauthorized file access and potential data exfiltration from systems running vulnerable versions of the software.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize XML input when processing zip files containing import data. When OpenRefine processes a zip archive, it extracts and parses XML content without adequate restrictions on external entity resolution. This allows attackers to construct malicious zip files containing XML documents with external entity declarations that reference local files on the server filesystem. The XXE processing occurs during the import operation, where the application's XML parser resolves these external entities, resulting in arbitrary file read operations that can access sensitive system files, configuration data, or other confidential information stored on the server.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gain unauthorized access to system resources and potentially escalate privileges. An attacker with the ability to upload or modify zip files that will be processed by OpenRefine can leverage this vulnerability to read arbitrary files, including database credentials, application configuration files, and other sensitive data. This represents a significant risk in environments where OpenRefine is used to process untrusted data from multiple sources, as it could allow attackers to extract valuable information from the underlying system infrastructure.
Security practitioners should consider this vulnerability in the context of CWE-611, which addresses improper access control in XML processing, and aligns with ATT&CK technique T1059.007 for XML External Entity Processing. Organizations using OpenRefine should immediately implement mitigations including upgrading to version 3.2 or later, which addresses this vulnerability through proper XML entity handling and input validation. Additional protective measures include restricting file upload capabilities, implementing strict file type validation, and monitoring import operations for suspicious activity. The vulnerability demonstrates the critical importance of proper XML processing security measures in applications that handle external data inputs, particularly those involving untrusted user-supplied content that may contain embedded XML structures.