CVE-2025-23817: MHR-Custom-Anti-Copy CSRF Vulnerability

CVE-2025-23817 Overview

CVE-2025-23817 is a Cross-Site Request Forgery (CSRF) vulnerability in the MHR-Custom-Anti-Copy WordPress plugin developed by mahadirz. This security flaw enables attackers to chain CSRF with Stored Cross-Site Scripting (XSS), allowing malicious actors to inject persistent scripts into the plugin's settings by tricking authenticated administrators into performing unintended actions.

Critical Impact

Attackers can leverage this vulnerability to execute arbitrary JavaScript code in the context of any user visiting affected pages, potentially leading to session hijacking, administrative account takeover, website defacement, or malware distribution to site visitors.

Affected Products

• MHR-Custom-Anti-Copy WordPress plugin version 2.0 and earlier
• WordPress installations with the mhr-custom-anti-copy plugin enabled
• Websites using this plugin for content protection functionality

Discovery Timeline

• January 16, 2025 - CVE-2025-23817 published to NVD
• April 15, 2026 - Last updated in NVD database

Technical Details for CVE-2025-23817

Vulnerability Analysis

This vulnerability represents a dangerous combination of two distinct web security flaws. The MHR-Custom-Anti-Copy plugin fails to implement proper CSRF token validation on its settings forms, allowing attackers to craft malicious requests that modify plugin configuration. When combined with insufficient input sanitization on these settings, attackers can inject malicious JavaScript that gets stored in the database and executed whenever the affected pages are loaded.

The plugin, designed to prevent content copying on WordPress sites, exposes its configuration endpoints without adequate security controls. This architectural weakness means that any authenticated administrator who visits a malicious webpage or clicks a crafted link could unknowingly save attacker-controlled content to their site's database.

Root Cause

The root cause of CVE-2025-23817 is the absence of nonce verification in the plugin's administrative form handlers combined with missing output encoding. WordPress provides built-in CSRF protection through nonces (wp_nonce_field() and wp_verify_nonce()), but this plugin does not properly implement these security mechanisms. Additionally, the plugin fails to sanitize and escape user-supplied input before storing it in the database and rendering it on the page, violating WordPress security best practices for both input validation and output encoding.

Attack Vector

The attack requires social engineering to succeed. An attacker would craft a malicious HTML page containing a hidden form that submits to the vulnerable plugin's settings endpoint. When an authenticated WordPress administrator visits this malicious page, their browser automatically sends the forged request with their valid session cookies, causing the malicious payload to be saved to the WordPress database.

The attack flow typically involves:

1. Attacker identifies a WordPress site using the vulnerable MHR-Custom-Anti-Copy plugin
2. Attacker crafts a webpage containing a hidden auto-submitting form targeting the plugin's settings
3. The form includes malicious JavaScript in the settings fields
4. Attacker tricks an administrator into visiting the malicious page (via phishing, forum posts, etc.)
5. The form auto-submits, saving the XSS payload to the WordPress database
6. Any visitor to the affected site now executes the attacker's JavaScript

For detailed technical information about the exploitation mechanism, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-23817

Indicators of Compromise

• Unexpected modifications to MHR-Custom-Anti-Copy plugin settings in wp_options table
• Suspicious JavaScript code in plugin configuration fields
• Unusual administrator activity from unfamiliar IP addresses or at unusual times
• Reports of browser warnings or unexpected redirects from site visitors

Detection Strategies

• Review WordPress admin activity logs for settings changes to the mhr-custom-anti-copy plugin
• Implement file integrity monitoring to detect unauthorized changes to WordPress database entries
• Deploy Web Application Firewall (WAF) rules to detect and block XSS payloads in POST requests
• Monitor for outbound connections to suspicious domains from your WordPress server

Monitoring Recommendations

• Enable WordPress audit logging plugins to track all administrative actions
• Configure alerts for any changes to plugin settings pages
• Implement Content Security Policy (CSP) headers to mitigate the impact of successful XSS attacks
• Regularly scan your WordPress database for suspicious script tags or event handlers in option values

How to Mitigate CVE-2025-23817

Immediate Actions Required

• Audit current MHR-Custom-Anti-Copy plugin settings for any suspicious or unexpected content
• Consider temporarily disabling the plugin until a patched version is available
• Review administrator accounts for any unauthorized access or activity
• Implement additional security layers such as a WAF with XSS protection rules

Patch Information

Check the Patchstack Vulnerability Report for the latest information on available patches. Organizations should update to a version newer than 2.0 when a security fix becomes available from the plugin developer.

Workarounds

• Deactivate and remove the MHR-Custom-Anti-Copy plugin until a secure version is released
• Implement Content Security Policy (CSP) headers to restrict script execution sources
• Use a WordPress security plugin that provides CSRF protection at the application level
• Restrict administrative access to trusted IP addresses only

# Add Content Security Policy header in .htaccess (Apache)
Header set Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' https://trusted-cdn.com; style-src 'self' 'unsafe-inline';"

# Or in nginx.conf
add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' https://trusted-cdn.com; style-src 'self' 'unsafe-inline';";