Software Engineering Institute

Netgear Management System NMS300 is a configuration, monitoring, and diagnostics utility for managing SNMP networked devices via a web interface.

CWE-434: Unrestricted Upload of File with Dangerous Type - CVE-2016-1524

Default installations of NMS300 operate two Java servlets, http://<IP>:8080/fileUpload.do and http://<IP>:8080/lib-1.0/external/flash/fileUpload.do, that can be accessed by unauthenticated users. By sending a specially crafted POST request to the servlets, an attacker can upload arbitrary files that will then be accessible from the NMS300 server's root directory as http://<IP>:8080/null<filename>. The NMS300 server runs with SYSTEM privileges.

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') - CVE-2016-1525

NMS300 contains a directory traversal vulnerability. An authenticated attacker can manipulate the realName parameter of a crafted POST request sent to http://<IP>:8080/data/config/image.do?method=add to load an arbitrary local file from the server host to a predictable location in the web service. The file can then be downloaded from http://<IP>:8080/data/config/image.do?method=export&imageId=<ID>, where <ID> is a count that increments by one every time a file is uploaded in this manner.

For more information, refer to Pedro Ribeiro's disclosure. The CVSS score describes CVE-2016-1524.

An unauthenticated attacker on the network can upload arbitrary files to the server's root web directory, leading to data creation and arbitrary code execution with SYSTEM privileges. An authenticated attacker on the network can access any file on the server host.

The CERT/CC is currently unaware of a practical solution to this problem and recommends the following workaround.

Restrict access

Enable firewall rules to restrict untrusted sources from accessing the web management interface.