CVE-2019-9613 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::$DATA to the admin/ueditor/uploadVideo URI.
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Analysis
by VulDB Data Team • 07/29/2023
The vulnerability identified as CVE-2019-9613 affects OFCMS versions prior to 1.1.3 and represents a critical security flaw in the file upload validation mechanism. This issue stems from inadequate filtering of file extensions and names, specifically failing to account for alternate data stream (ADS) techniques that allow attackers to bypass security restrictions. The vulnerability is particularly concerning because it affects the admin/ueditor/uploadVideo URI endpoint, which is designed to handle video file uploads within the content management system's administrative interface.
The technical flaw manifests in the system's insufficient validation of uploaded files, where the protection mechanisms only block traditional file extensions such as .jsp and .jspx but fail to consider advanced file system techniques like Windows alternate data streams. When an attacker uploads a file with a name such as file.jsp::$DATA, the system incorrectly processes this as a valid upload because the filename validation logic does not properly sanitize or detect these alternate data stream indicators. This bypass occurs at the file system level where Windows supports alternate data streams that can contain executable code while appearing to be benign files.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code on the target system with the privileges of the web application. Attackers can leverage this flaw to upload malicious web shell files or other executable content that can be executed through the web server, potentially leading to complete system compromise. The vulnerability enables attackers to gain persistent access to the server, escalate privileges, and conduct further reconnaissance or attack activities within the network environment. This type of vulnerability falls under CWE-434 Unrestricted Upload of File with Dangerous Type, which is categorized as a critical weakness in the CWE taxonomy.
The attack vector for this vulnerability aligns with ATT&CK technique T1190 Exploit Public-Facing Application, as it targets a publicly accessible web application interface. The exploitation process involves uploading a malicious file through the vulnerable upload endpoint, which then gets executed on the server. This vulnerability demonstrates a classic case of inadequate input validation and improper file handling, where the system assumes that simply blocking certain extensions is sufficient to prevent malicious uploads. The weakness creates a path for attackers to establish a foothold in the system and potentially move laterally within the network.
Mitigation strategies should include implementing comprehensive file validation that checks not only the file extension but also the file content, using techniques such as MIME type validation, file signature verification, and proper sanitization of filenames. Organizations should ensure that all file upload mechanisms properly handle alternate data streams and implement strict access controls for upload directories. The recommended fix involves upgrading to OFCMS version 1.1.3 or later, which includes proper validation of file names and content, and implementing additional security measures such as restricting file upload permissions, using secure file storage locations, and implementing web application firewalls to detect and block suspicious upload attempts.