CVE-2019-9609 in OFCMS
Summary
by MITRE
An issue was discovered in OFCMS before 1.1.3. Remote attackers can execute arbitrary code because blocking of .jsp and .jspx files does not consider (for example) file.jsp::$DATA to the admin/comn/service/editUploadImage URI.
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Analysis
by VulDB Data Team • 07/29/2023
The vulnerability identified as CVE-2019-9609 affects OFCMS versions prior to 1.1.3 and represents a critical security flaw in the file upload validation mechanism. This issue stems from inadequate filtering of file extensions and naming conventions that allows attackers to bypass security controls designed to prevent execution of malicious code. The vulnerability specifically impacts the admin/comn/service/editUploadImage URI endpoint where the system fails to properly validate file names that contain alternate data streams or unconventional naming patterns. The flaw demonstrates a classic bypass technique where attackers can exploit the system's limited understanding of file system structures to upload malicious files that would otherwise be blocked by traditional extension filtering methods.
The technical root cause of this vulnerability aligns with CWE-434, which describes insecure file upload handling in web applications. Attackers can leverage the Windows alternate data streams feature by naming malicious files with patterns such as file.jsp::$DATA, where the::$DATA portion represents an alternate data stream that bypasses standard file extension checks. This technique exploits the fact that the application's security controls only examine the primary file extension while ignoring the underlying file system attributes and alternate data stream mechanisms. The vulnerability operates at the application layer and can be classified under the ATT&CK technique T1190 - Exploit Public-Facing Application, specifically targeting web application security controls.
The operational impact of this vulnerability is severe as it enables remote code execution without authentication, allowing attackers to upload and execute malicious code on the target server. This provides attackers with a persistent backdoor into the system, potentially leading to full system compromise, data exfiltration, and lateral movement within the network. The vulnerability affects the administrative functionality of the CMS, meaning that successful exploitation could result in complete control over the content management system and potentially the entire underlying infrastructure. The attack surface is particularly concerning given that the vulnerability exists in a high-privilege administrative endpoint that typically requires elevated permissions to access.
Mitigation strategies should focus on implementing comprehensive file validation mechanisms that consider the entire file system structure rather than relying solely on extension filtering. Organizations should implement proper input validation that checks for alternate data streams and unconventional file naming patterns. The recommended approach includes implementing a whitelist-based file type validation system that explicitly defines allowed file extensions and content types rather than relying on blacklisting. Additionally, the application should enforce strict file naming conventions and validate all aspects of uploaded files including metadata, file attributes, and system-specific naming patterns. System administrators should also implement proper access controls and network segmentation to limit the potential impact of successful exploitation, while ensuring that all systems are updated to OFCMS version 1.1.3 or later where this vulnerability has been addressed through improved file validation controls.