CVE-2025-30006

Executive Summary

CVE-2025-30006 identifies a reflected cross-site scripting (XSS) vulnerability in the administrative control panel of Xorcom CompletePBX. This flaw allows an unauthenticated attacker to inject arbitrary JavaScript into a reflected response, potentially leading to session hijacking, credential theft, or administrative actions on behalf of a logged-in admin. The vulnerability affects all versions prior to 5.2.35. With a CVSS score of 6.1 (Medium), the risk is elevated due to the lack of authentication required for exploitation and the high privileges of the target interface. No public proof-of-concept or exploit code has been released, but the vulnerability is confirmed by the vendor advisory.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed to trigger the XSS.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (SC): Changed (C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): None (N) – No impact on availability.

Threat Level: Medium. The XSS is reflected and requires user interaction, but the administrative context makes it dangerous for privilege escalation.

Deep Dive & Mechanics

The vulnerability resides in the administrative web interface of CompletePBX. The application fails to properly sanitize user-supplied input in a specific parameter before reflecting it in the HTTP response. An attacker can craft a malicious URL containing JavaScript payloads. When an authenticated administrator clicks the link, the script executes in the context of the admin session, allowing the attacker to:

• Steal session cookies.
• Perform administrative actions (e.g., add users, modify configurations).
• Redirect to phishing pages.
• Execute further attacks against internal network resources.

The root cause is insufficient output encoding in the administrative panel's response handling. The application likely uses a templating engine that does not escape HTML entities by default, or the developer manually inserted user input without proper sanitization.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// In a PHP controller
$param = $_GET['page'];
echo "<div class='content'>" . $param . "</div>";

Patched Code (Conceptual):

// Properly escape output
$param = htmlspecialchars($_GET['page'], ENT_QUOTES, 'UTF-8');
echo "<div class='content'>" . $param . "</div>";

The patch in version 5.2.35 likely implements proper output encoding for all user-controlled parameters in the admin panel.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy Xorcom CompletePBX version 5.2.34 in a virtualized environment.
2. Access the admin panel at https://<target>/admin/.
3. Identify the vulnerable parameter (e.g., page, error, msg).

Exploitation Steps:

1. Craft a malicious URL:

   https://<target>/admin/index.php?page=<script>alert('XSS')</script>
   

2. Send the link to an authenticated admin via email or social engineering.
3. When the admin clicks, the script executes.

Advanced Payload:

<script>
fetch('/admin/config.php?action=add_user&username=attacker&password=evilpass&role=admin');
</script>

Blue Team

Detection:

• Monitor for unusual URL parameters containing <script>, onerror, onload, or base64-encoded JavaScript.
• Alert on admin panel access from unexpected IPs or user agents.
• Use web application firewalls (WAF) to block reflected XSS patterns.

Mitigation:

• Immediately upgrade to version 5.2.35 or later.
• If patching is not possible, implement a WAF rule to block reflected XSS.
• Restrict admin panel access to trusted IPs only.
• Enforce Content Security Policy (CSP) headers.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /admin/ with parameters containing <script> or javascript:.
  • Outbound connections to attacker-controlled domains from the PBX server.
• File IOCs:
  • Suspicious entries in web server logs (e.g., GET /admin/index.php?page=<script>...).
• Behavioral IOCs:
  • Unauthorized admin user creation.
  • Unexpected configuration changes in the PBX.

Detection Engineering

YARA Rule

rule CVE_2025_30006_XSS_Reflected {
    meta:
        description = "Detects reflected XSS attempts against Xorcom CompletePBX admin panel"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-30006"
    strings:
        $xss1 = "<script>" nocase
        $xss2 = "onerror=" nocase
        $xss3 = "onload=" nocase
        $xss4 = "javascript:" nocase
        $admin_path = "/admin/" nocase
    condition:
        any of ($xss*) and $admin_path
}

Sigma Rule

title: Reflected XSS Attempt Against Xorcom CompletePBX Admin
id: 8a3f7c2e-5d1b-4a9f-8c6e-2b1d3f4a5c6e
status: experimental
description: Detects reflected XSS payloads in HTTP requests to CompletePBX admin panel
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - '<script>'
            - 'onerror='
            - 'onload='
            - 'javascript:'
        cs-uri-stem|contains: '/admin/'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in admin panel (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-30006 Reflected XSS in Xorcom CompletePBX Admin"; flow:to_server,established; content:"/admin/"; http_uri; content:"<script>"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Upgrade to Xorcom CompletePBX version 5.2.35 or later.
2. Workaround: If patching is delayed, implement a WAF rule to block reflected XSS patterns.
3. Long-term: Conduct a security audit of the admin panel for other injection flaws.
4. Monitoring: Enable detailed logging for the admin panel and review logs for suspicious activity.
5. Training: Educate administrators about phishing attacks targeting the PBX.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert