CVE-2025-39571

Executive Summary

CVE-2025-39571 is a Missing Authorization vulnerability in the WordPress plugin WowStore (product-blocks) developed by WPXPO. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or modification. The vulnerability affects all versions up to and including 4.2.4. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time, but the risk remains due to the lack of a patch.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem. WordPress plugins are distributed via the official WordPress Plugin Directory or third-party marketplaces. The absence of a patch means that any site running WowStore <= 4.2.4 is vulnerable. Administrators should monitor the plugin's update channel and consider disabling the plugin until a fix is available.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
• Base Score: 4.3 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: None (C:N)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low integrity compromise. However, the lack of a patch elevates the urgency for mitigation.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check (CWE-862) in the WowStore plugin's REST API endpoints or AJAX handlers. The plugin likely exposes functions that modify product blocks or store settings without verifying the user's capabilities. An unauthenticated attacker can send crafted HTTP requests to these endpoints to:

• Modify product block configurations.
• Alter store settings.
• Potentially inject malicious content into product blocks.

The flaw is in the product-blocks component, which handles the display and management of WooCommerce product blocks. The plugin fails to call current_user_can() or similar authorization checks before executing sensitive operations.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical fix would involve adding capability checks to all REST API endpoints and AJAX actions. Below is an example of vulnerable vs. patched code.

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_wowstore_update_block', 'wowstore_update_block');
function wowstore_update_block() {
    // No authorization check
    $block_id = $_POST['block_id'];
    $new_data = $_POST['data'];
    update_post_meta($block_id, '_wowstore_block_data', $new_data);
    wp_die();
}

Patched Code (PHP):

add_action('wp_ajax_wowstore_update_block', 'wowstore_update_block');
function wowstore_update_block() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    $block_id = $_POST['block_id'];
    $new_data = $_POST['data'];
    update_post_meta($block_id, '_wowstore_block_data', $new_data);
    wp_die();
}

Note: The patched version removes the nopriv hook, ensuring only authenticated users with proper capabilities can access the function.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with WowStore <= 4.2.4 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=wowstore_update_block).
2. Craft a POST request with malicious data:

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=wowstore_update_block&block_id=123&data=malicious_content"

3. Verify the change by visiting the product page.

Note: No public exploit code is available; this is a hypothetical demonstration.

Blue Team

Detection:

• Monitor for unusual POST requests to /wp-admin/admin-ajax.php with action parameters containing wowstore.
• Look for requests from unauthenticated users (no Cookie header with WordPress auth cookies).
• Alert on changes to product block meta data (_wowstore_block_data).

Hunting:

• Search logs for wowstore_update_block or wowstore_ actions.
• Review recent modifications to product blocks in the database.

Indicators of Compromise (IOCs)

• Network:
  • POST requests to /wp-admin/admin-ajax.php with action=wowstore_* from unauthenticated sources.
  • Unusual block_id values (e.g., non-existent IDs).
• Host:
  • Modified _wowstore_block_data post meta entries.
  • Unexpected product block content on the frontend.
• File:
  • Modified plugin files (e.g., wp-content/plugins/wowstore/product-blocks.php).

Detection Engineering

YARA Rule

rule CVE_2025_39571_WowStore_Missing_Auth {
    meta:
        description = "Detects WowStore plugin files with missing authorization"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-39571"
    strings:
        $vuln_func = "wp_ajax_nopriv_wowstore" nocase
        $auth_check = "current_user_can" nocase
    condition:
        $vuln_func and not $auth_check
}

Sigma Rule

title: WowStore Missing Authorization Exploitation
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects exploitation attempts of CVE-2025-39571
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-ajax.php'
        cs-uri-query: 'action=wowstore_*'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-39571 WowStore Missing Authorization Exploit";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=wowstore_"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the WowStore plugin until a patch is released.
2. Implement a Web Application Firewall (WAF) rule to block requests to /wp-admin/admin-ajax.php with action parameters starting with wowstore_ from unauthenticated users.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the official patch once released by WPXPO.
• If custom development is possible, add capability checks to all AJAX handlers as shown in the patched code example.

Workaround:

• Use a security plugin (e.g., Wordfence) to add virtual patching for this vulnerability.

Valters IT
Securing Digital Frontiers