CVE-2025-26975

Executive Summary

CVE-2025-26975 is a Missing Authorization vulnerability in the Strong Testimonials WordPress plugin by WP Chill. This flaw allows unauthenticated attackers to access functionality that should be protected by Access Control Lists (ACLs). The vulnerability affects all versions from n/a through 3.2.3. With a CVSS score of 5.3 (Medium), it poses a risk of unauthorized information disclosure or limited functionality abuse. No public proof-of-concept (PoC) or exploit code has been released, and the patch status is currently unknown.

WordPress Ecosystem Context

This vulnerability is specific to the WordPress plugin ecosystem. It is not related to Apache or Nginx server software. The plugin "Strong Testimonials" is used to manage and display customer testimonials on WordPress sites. The missing authorization could allow attackers to view, modify, or delete testimonials without proper authentication.

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): None (N) – No user action required.
• Scope (S): Unchanged (U) – Vulnerability affects only the vulnerable component.
• Confidentiality (C): Low (L) – Limited information disclosure.
• Integrity (I): None (N) – No data modification.
• Availability (A): None (N) – No denial of service.

Threat Level: Medium. The lack of authentication requirements makes this easily exploitable, but the impact is limited to low confidentiality loss.

Deep Dive & Mechanics

The vulnerability resides in the Strong Testimonials plugin's AJAX handlers or REST API endpoints. The plugin likely exposes functions for managing testimonials (e.g., adding, editing, deleting) without proper capability checks. In WordPress, such actions should require the edit_posts or manage_options capability. However, due to missing current_user_can() checks, unauthenticated users can trigger these actions.

Root Cause: The plugin fails to validate user permissions before executing sensitive operations. This is a classic CWE-862 (Missing Authorization) issue.

Attack Vector: An attacker sends crafted HTTP requests to the vulnerable endpoints. For example, a POST request to /wp-admin/admin-ajax.php with an action parameter that triggers testimonial deletion.

Impact: Attackers could:

• View all testimonials (including private ones).
• Delete testimonials.
• Potentially inject malicious content if the plugin allows unauthenticated submissions.

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize the fix. The vulnerable code likely looks like:

// Vulnerable: No capability check
add_action('wp_ajax_nopriv_delete_testimonial', 'delete_testimonial_callback');
function delete_testimonial_callback() {
    $id = $_POST['id'];
    wp_delete_post($id);
    wp_die();
}

The patched version would include:

// Patched: Capability check added
add_action('wp_ajax_delete_testimonial', 'delete_testimonial_callback');
function delete_testimonial_callback() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    $id = $_POST['id'];
    wp_delete_post($id);
    wp_die();
}

Note: The nopriv prefix in the action hook allows unauthenticated access. Removing it and adding capability checks is the standard fix.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• Target WordPress site with Strong Testimonials <= 3.2.3.
• No authentication required.

Exploitation Steps:

1. Identify Vulnerable Endpoints: Use a tool like Burp Suite or curl to probe AJAX actions. Common actions might include strong_testimonials_delete, strong_testimonials_view_all, etc.

2. Craft Exploit Request: Send a POST request to the WordPress admin-ajax.php endpoint.

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=strong_testimonials_delete&id=123"

3. Verify Impact: Check if the testimonial with ID 123 is deleted or if unauthorized data is returned.

Note: No public exploit code is available. The above is a generic example based on common patterns.

Blue Team (Defense & Detection)

Detection Steps:

• Monitor for unusual AJAX requests to /wp-admin/admin-ajax.php with actions related to "strong_testimonials".
• Look for requests from unauthenticated users (no Cookie header with WordPress auth cookies).
• Check logs for 403 errors if a patch is applied.

Honeypot: Deploy a fake testimonial endpoint to lure attackers.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=strong_testimonials_* parameters.
  • Requests lacking WordPress authentication cookies.
• File IOCs:
  • Modified or deleted testimonial posts in the WordPress database.
• Log IOCs:
  • Unusual entries in WordPress debug.log or server access logs showing AJAX calls from unknown IPs.

Detection Engineering

YARA Rule

rule Detect_Strong_Testimonials_Missing_Auth {
    meta:
        description = "Detects attempts to exploit CVE-2025-26975 in Strong Testimonials plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-26975"
    strings:
        $ajax_action = /action=strong_testimonials_[a-z_]+/
        $admin_ajax = "admin-ajax.php"
    condition:
        $admin_ajax and $ajax_action
}

Sigma Rule

title: CVE-2025-26975 Strong Testimonials Missing Authorization
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects unauthenticated AJAX requests to Strong Testimonials endpoints
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-ajax.php'
        cs-uri-query: 'action=strong_testimonials_*'
    condition: selection
falsepositives:
    - Legitimate admin actions (if authenticated)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-26975 Strong Testimonials Missing Authorization"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=strong_testimonials_"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to admin-ajax.php with strong_testimonials actions.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the official patch from WP Chill when available.
• Update to the latest version of Strong Testimonials (if a patched version > 3.2.3 is released).
• Conduct a security audit of all WordPress plugins for similar missing authorization issues.

Workaround:

• Add custom code to your theme's functions.php to enforce capability checks:

add_action('init', function() {
    if (defined('DOING_AJAX') && DOING_AJAX) {
        $action = $_REQUEST['action'] ?? '';
        if (strpos($action, 'strong_testimonials_') === 0 && !is_user_logged_in()) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT
Securing Digital Frontiers