CVE-2025-25110

Executive Summary

CVE-2025-25110 is a Missing Authorization vulnerability in the WordPress plugin Event Kikfyre (kikfyre-events-calendar-tickets) by Metagauss. 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 2.1.8. No official patch has been released, and the vendor has not responded to disclosure attempts. The EPSS score is 0.0%, indicating low exploitation likelihood 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. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users are advised to monitor for updates and consider removing the plugin if no patch is forthcoming.

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
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low-level data exposure or modification.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the plugin's REST API endpoints or AJAX handlers. The plugin likely exposes functions that should require administrative or editor-level privileges but fails to verify the user's capabilities. An attacker can send crafted HTTP requests to these endpoints to perform actions such as:

• Viewing or modifying event data
• Accessing ticket information
• Changing plugin settings

The exact vulnerable endpoint is not publicly documented, but common patterns in WordPress plugins include:

• wp-json/kikfyre/v1/events
• admin-ajax.php?action=kikfyre_update_event

The lack of a current_user_can() check or nonce verification allows unauthenticated access.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described generically:

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_kikfyre_update_event', 'kikfyre_update_event_callback');
function kikfyre_update_event_callback() {
    // No capability check
    $event_id = $_POST['event_id'];
    update_post_meta($event_id, 'kikfyre_ticket_price', $_POST['price']);
    wp_send_json_success();
}

Patched Code (Hypothetical):

add_action('wp_ajax_kikfyre_update_event', 'kikfyre_update_event_callback');
function kikfyre_update_event_callback() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized');
    }
    check_ajax_referer('kikfyre_nonce', 'nonce');
    $event_id = intval($_POST['event_id']);
    update_post_meta($event_id, 'kikfyre_ticket_price', sanitize_text_field($_POST['price']));
    wp_send_json_success();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Event Kikfyre <= 2.1.8 installed and activated.
• No authentication required.

Exploit Steps:

1. Identify the vulnerable endpoint by analyzing the plugin's JavaScript or PHP files.
2. Send a crafted HTTP request to the endpoint.

Example cURL command:

curl -X POST 'http://target.com/wp-admin/admin-ajax.php' \
  -d 'action=kikfyre_update_event&event_id=1&price=0.00'

Expected Result: The event ticket price is modified without authentication.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual POST requests to admin-ajax.php with action parameters starting with kikfyre_.
• Look for requests from unauthenticated users to plugin-specific REST endpoints.

Hardening:

• Disable the plugin until a patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests to kikfyre_* actions from unauthenticated users.
• Use a WordPress security plugin to enforce capability checks.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=kikfyre_* parameters.
  • GET/POST requests to /wp-json/kikfyre/v1/* endpoints.
• File IOCs:
  • Modified post meta fields like kikfyre_ticket_price without corresponding admin actions.
• Log IOCs:
  • Unauthorized access attempts logged in WordPress debug.log or server access logs.

Detection Engineering

YARA Rule

rule Detect_Event_Kikfyre_Exploit {
    meta:
        description = "Detects exploitation attempts of CVE-2025-25110 in Event Kikfyre plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-25110"
    strings:
        $action = "kikfyre_" ascii wide nocase
        $ajax = "admin-ajax.php" ascii wide nocase
        $rest = "kikfyre/v1" ascii wide nocase
    condition:
        any of ($action) and any of ($ajax, $rest)
}

Sigma Rule

title: CVE-2025-25110 Event Kikfyre Missing Authorization
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated access to Event Kikfyre plugin endpoints
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - 'admin-ajax.php'
            - 'kikfyre/v1'
        cs-uri-query|re: 'action=kikfyre_'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-25110 Event Kikfyre Missing Authorization Exploit"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=kikfyre_"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Implement WAF rules to block unauthenticated requests to kikfyre_* actions.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• The vendor must release a patched version that adds proper capability checks and nonce verification.
• Users should consider migrating to an alternative event management plugin.

Workaround:

• Add the following code to the theme's functions.php to block unauthenticated access:

add_action('init', function() {
    if (defined('DOING_AJAX') && DOING_AJAX) {
        if (isset($_POST['action']) && strpos($_POST['action'], 'kikfyre_') === 0) {
            if (!is_user_logged_in()) {
                wp_die('Unauthorized');
            }
        }
    }
});

Valters IT
Securing Digital Frontiers