CVE-2021-44147 in FileMaker Pro
Summary
by MITRE • 11/23/2021
An XML External Entity issue in Claris FileMaker Pro and Server (including WebDirect) before 19.4.1 allows a remote attacker to disclose local files via a crafted XML/Excel document and perform server-side request forgery attacks.
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Analysis
by VulDB Data Team • 11/27/2021
The vulnerability identified as CVE-2021-44147 represents a critical XML External Entity (XXE) flaw affecting Claris FileMaker Pro and Server products, including the WebDirect component. This issue stems from inadequate input validation within the XML processing functionality of these applications, creating a pathway for remote attackers to exploit the system through maliciously crafted XML or Excel documents. The vulnerability specifically impacts versions prior to 19.4.1, indicating that organizations running older iterations of the software remain at significant risk of exploitation.
The technical implementation of this vulnerability allows attackers to leverage XML external entity processing mechanisms to access local system resources and execute server-side request forgery operations. When the vulnerable applications process crafted XML documents, they fail to properly sanitize external entity references, enabling attackers to reference local files on the server filesystem. This misconfiguration creates a direct information disclosure channel where sensitive data can be retrieved from the target system without proper authentication or authorization. The XXE vulnerability operates at the application layer, bypassing traditional network security controls by leveraging legitimate XML parsing functionality.
From an operational perspective, this vulnerability presents substantial risk to organizations utilizing Claris FileMaker products, particularly those with web-facing applications or remote access capabilities. Attackers can exploit the flaw to access sensitive files including database credentials, configuration files, and other system artifacts that may contain proprietary information or authentication tokens. The server-side request forgery component amplifies the threat by allowing attackers to make arbitrary requests from the vulnerable server, potentially enabling lateral movement within networks or access to backend services that would otherwise be isolated from direct external access. This vulnerability directly maps to CWE-611 (Improper Restriction of XML External Entity Reference) and aligns with ATT&CK technique T1071.004 (Application Layer Protocol: DNS) when used for data exfiltration.
Organizations should prioritize immediate remediation by upgrading to Claris FileMaker Pro and Server version 19.4.1 or later, which includes proper XML external entity validation and sanitization measures. Network segmentation and access controls should be implemented to limit exposure of vulnerable applications to untrusted networks, while regular security assessments should monitor for potential exploitation attempts. Additionally, organizations should implement web application firewalls and content filtering mechanisms to detect and block suspicious XML content, and establish monitoring procedures to identify unauthorized file access attempts. The vulnerability demonstrates the importance of proper input validation and secure coding practices, particularly when processing external data sources, and serves as a reminder of the critical need for regular security updates and patch management programs.