CVE-2024-51496: LibreNMS has a Reflected XSS ('Cross-site Scripting') in librenms/includes/html/pages/wireless.inc.php

Summary A Reflected Cross-Site Scripting (XSS) vulnerability in the "metric" parameter of the "/wireless" and "/health" endpoints allows attackers to inject arbitrary JavaScript. This vulnerability results in the execution of malicious code when a user accesses the page with a malicious "metric" parameter, potentially compromising their session and allowing unauthorized actions.

Details The "/wireless" and "/health" endpoints are vulnerable to reflected XSS in the "metric" parameter. An attacker can inject the following XSS payload into the "metric" parameter: <script>constructor'constructor')();<!---->

When the page is loaded with this malicious parameter, the script executes immediately. The vulnerability occurs due to improper sanitization of the "metric" parameter in the following sinks: https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/html/pages/wireless.inc.php#L82 https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/html/pages/health.inc.php#L114

PoC 1. Inject the following payload into the "metric" parameter of the "/wireless" or "/health" endpoint: <script>constructor'constructor')();<!----> 2. Access the page with the injected payload. 3. Observe that the injected script executes upon loading the page.

Example URL: http://<yoururl>/wireless/metric=%3Cscript%3Econstructor'constructor')();%3C!----%3E

Example Request: http GET /wireless/metric=%3Cscript%3Econstructor%27constructor%27)();%3C!----%3E HTTP/1.1 Host: <yourhost> Cookie: <your cookies>

Impact

This vulnerability allows attackers to execute arbitrary JavaScript in the context of a user’s session by crafting a malicious URL. The attack could lead to session hijacking, unauthorized actions, or further exploitation by injecting malicious scripts.