CVE-2016-6600 in WebNMS Framework
Summary
by MITRE
Directory traversal vulnerability in the file upload functionality in ZOHO WebNMS Framework 5.2 and 5.2 SP1 allows remote attackers to upload and execute arbitrary JSP files via a .. (dot dot) in the fileName parameter to servlets/FileUploadServlet.
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Analysis
by VulDB Data Team • 05/14/2026
The CVE-2016-6600 vulnerability represents a critical directory traversal flaw within the ZOHO WebNMS Framework version 5.2 and its service pack 1, specifically affecting the file upload servlet functionality. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly handle malicious file names containing directory traversal sequences. The flaw exists in the FileUploadServlet component which processes file upload requests from remote attackers without sufficient restrictions on the fileName parameter, allowing unauthorized users to manipulate the upload destination path.
The technical exploitation of this vulnerability occurs through the deliberate insertion of .. (dot dot) sequences within the fileName parameter during file upload operations. When an attacker submits a file name containing directory traversal sequences such as ../../../../../etc/passwd.jsp, the vulnerable application fails to properly sanitize this input, resulting in the file being written to an unintended directory location outside the intended upload folder. This misconfiguration enables attackers to place malicious JSP files in directories accessible via the web server, effectively bypassing normal file upload restrictions and gaining the ability to execute arbitrary code on the target system.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, as it provides attackers with a pathway to achieve remote code execution within the target environment. Successful exploitation allows adversaries to deploy web shells, backdoors, or other malicious payloads that can be used for persistent access, data exfiltration, or further network reconnaissance. The vulnerability particularly affects organizations using ZOHO WebNMS Framework in production environments where web applications are exposed to untrusted users, as it essentially grants attackers the capability to compromise the entire web application server through a single vulnerable upload endpoint.
Security implications of CVE-2016-6600 align with CWE-22 directory traversal vulnerabilities and can be mapped to ATT&CK techniques such as T1190 for exploitation of vulnerabilities and T1059 for execution through web shells. Organizations utilizing the affected ZOHO WebNMS Framework versions face significant risk of unauthorized access and potential system compromise, particularly in environments where proper input validation and access controls are not implemented at the application layer. The vulnerability demonstrates the critical importance of implementing proper file name sanitization, validating upload destinations, and restricting file type and path manipulation in web applications. Organizations should implement immediate mitigations including input validation, path restriction, and proper access controls to prevent exploitation of this vulnerability, as well as upgrade to patched versions of the ZOHO WebNMS Framework when available. The flaw serves as a reminder of the fundamental security principle that all user-supplied input must be rigorously validated and sanitized before processing, particularly in file handling operations where directory traversal attacks can lead to complete system compromise.