CVE-2019-9616 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::$DATA to the admin/ueditor/uploadScrawl URI.
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Analysis
by VulDB Data Team • 07/29/2023
The vulnerability identified as CVE-2019-9616 affects OFCMS versions prior to 1.1.3 and represents a critical security flaw in the file upload validation mechanism. This issue stems from insufficient filtering of file extensions and naming conventions that attackers can exploit to bypass security controls. The vulnerability specifically impacts the admin/ueditor/uploadScrawl URI endpoint where file uploads are processed, making it a prime target for remote code execution attacks. The flaw demonstrates a fundamental weakness in the application's defense-in-depth strategy, where traditional file extension blocking mechanisms prove inadequate against advanced evasion techniques.
The technical exploitation of this vulnerability relies on the Windows file system's alternate data streams feature, which allows files to be stored with special naming conventions such as file.jsp::$DATA. This technique leverages the fact that many security filtering mechanisms only inspect the primary file extension while ignoring the presence of alternate data streams that can contain malicious code. The bypass occurs because the application's security controls fail to account for these sophisticated file naming patterns that can be used to disguise malicious payloads within seemingly benign file uploads. This approach aligns with attack techniques documented in the ATT&CK framework under the T1059.007 sub-technique for "Command and Scripting Interpreter: PowerShell" and T1074.001 for "Data Staged: Local Data Staging" where attackers manipulate file system attributes to evade detection.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code on the affected server with the privileges of the web application. This provides attackers with a persistent backdoor into the system, enabling them to establish further footholds, escalate privileges, and potentially compromise the entire network infrastructure. The vulnerability affects the content management system's file upload functionality, which is a critical component for managing website content, making it particularly dangerous for organizations relying on OFCMS for their web presence. The exploitability of this issue means that any user with access to the upload endpoint can potentially compromise the entire system without requiring additional authentication or privileges.
Security mitigations for CVE-2019-9616 should focus on implementing comprehensive file validation mechanisms that account for all possible file naming conventions and system attributes. Organizations should upgrade to OFCMS version 1.1.3 or later where this vulnerability has been patched. The solution involves implementing strict file validation that examines not only the primary file extension but also checks for alternate data streams and other file system attributes. This aligns with CWE-434 which addresses the weakness of unrestricted file upload and the importance of validating file characteristics beyond simple extension checks. Additional protective measures include implementing proper input sanitization, using secure file upload libraries, and deploying web application firewalls that can detect and block suspicious file upload patterns. The mitigation strategy should also incorporate regular security testing and monitoring of file upload endpoints to identify potential bypass attempts and maintain continuous protection against similar vulnerabilities.