CVE-2025-62018

Executive Summary

CVE-2025-62018 is a Missing Authorization vulnerability in the KALLYAS WordPress theme by Hogash, affecting versions up to and including 4.22.0. This flaw allows unauthenticated attackers to access unauthorized functionality or data due to insufficient access controls on certain theme components. The vulnerability has a CVSS score of 5.3 (Medium), with a low confidentiality impact but no integrity or availability impact. No public proof-of-concept (PoC) or exploit code has been released, and no patch is currently available from the vendor.

WordPress Ecosystem Context

This vulnerability is specific to the KALLYAS WordPress theme. It is not related to Apache, Nginx, or any other web server software. The issue lies within the theme's PHP code, where authorization checks are missing on certain AJAX actions or REST endpoints.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerable component remains isolated.
• Confidentiality (C): Low (L) – Limited information disclosure possible.
• Integrity (I): None (N) – No data modification.
• Availability (A): None (N) – No denial of service.

Threat Level: Medium. While the impact is limited to low confidentiality, the lack of authentication requirements makes it trivially exploitable for information gathering.

Deep Dive & Mechanics

The KALLYAS theme registers several AJAX handlers and REST API endpoints for frontend functionality (e.g., demo import, theme options, or custom post types). Due to missing current_user_can() checks or capability verifications, these endpoints are accessible to unauthenticated users.

Root Cause: The theme's PHP code likely uses wp_ajax_nopriv_* hooks without proper capability validation, or exposes REST routes without permission_callback arguments.

Attack Vector: An attacker sends crafted HTTP requests to the vulnerable endpoints, potentially retrieving sensitive configuration data, user lists, or theme settings.

Example vulnerable endpoint pattern:

add_action('wp_ajax_nopriv_kallyas_get_data', 'kallyas_get_data_callback');
function kallyas_get_data_callback() {
    // No capability check
    $data = get_option('kallyas_theme_options');
    wp_send_json($data);
}

Vulnerable vs. Patched Code

Vulnerable Code (<= 4.22.0):

add_action('wp_ajax_nopriv_kallyas_export_settings', 'kallyas_export_settings');
function kallyas_export_settings() {
    // Missing authorization check
    $settings = get_option('kallyas_theme_settings');
    echo json_encode($settings);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_kallyas_export_settings', 'kallyas_export_settings');
add_action('wp_ajax_nopriv_kallyas_export_settings', function() {
    wp_die('Unauthorized', 401);
});
function kallyas_export_settings() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 401);
    }
    $settings = get_option('kallyas_theme_settings');
    echo json_encode($settings);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target running WordPress with KALLYAS theme <= 4.22.0
• Network access to the WordPress site

Exploitation Steps:

1. Identify vulnerable endpoints by analyzing theme source code or using fuzzing.
2. Send a direct HTTP request to the endpoint:

curl -X GET "http://target/wp-admin/admin-ajax.php?action=kallyas_export_settings"

3. If successful, the response will contain sensitive data (e.g., theme options, API keys).

Automated Scanning:

# Using nuclei (if template becomes available)
nuclei -u http://target -t cves/2025/CVE-2025-62018.yaml

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with action parameters starting with kallyas_.
• Alert on requests to REST endpoints under /wp-json/kallyas/v1/ from unauthenticated users.

Hardening:

• Apply the principle of least privilege: ensure all AJAX handlers check current_user_can().
• Use a Web Application Firewall (WAF) to block requests to known vulnerable endpoints.
• Disable unused theme features via functions.php:

remove_action('wp_ajax_nopriv_kallyas_export_settings', 'kallyas_export_settings');

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to /wp-admin/admin-ajax.php with action=kallyas_* parameters from unauthenticated IPs.
• REST API requests to /wp-json/kallyas/v1/* without valid nonce or authentication.

File IOCs:

• Modified theme files in /wp-content/themes/kallyas/ containing unauthorized access patterns.
• Suspicious log entries in WordPress debug log (wp-content/debug.log) showing failed capability checks.

Behavioral IOCs:

• Unusual spikes in AJAX requests from single IP addresses.
• Access to theme options or settings pages by non-admin users.

Detection Engineering

YARA Rule

rule CVE_2025_62018_KALLYAS_Auth_Bypass {
    meta:
        description = "Detects missing authorization in KALLYAS theme AJAX handlers"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-62018"
    strings:
        $ajax_nopriv = "wp_ajax_nopriv_kallyas_" ascii wide nocase
        $rest_route = "kallyas/v1" ascii wide nocase
        $no_cap = "current_user_can" ascii wide nocase
    condition:
        ($ajax_nopriv or $rest_route) and not $no_cap
}

Sigma Rule

title: CVE-2025-62018 KALLYAS Missing Authorization Detection
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects unauthenticated access to KALLYAS theme AJAX endpoints
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'action=kallyas_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin users accessing theme settings
level: medium

Suricata Rule

alert http any any -> $EXTERNAL_NET any (
    msg:"CVE-2025-62018 KALLYAS Missing Authorization Attempt";
    flow:to_server,established;
    content:"/wp-admin/admin-ajax.php";
    http_uri;
    content:"action=kallyas_";
    http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-62018;
)

Remediation & Mitigation

Immediate Actions:

1. Disable vulnerable endpoints by adding the following to the theme's functions.php:

add_action('init', function() {
    remove_all_actions('wp_ajax_nopriv_kallyas_export_settings');
    remove_all_actions('wp_ajax_nopriv_kallyas_get_data');
});

2. Implement a WAF rule to block requests containing action=kallyas_ in the query string for unauthenticated users.
3. Monitor logs for exploitation attempts using the Sigma rule above.

Long-term Fix:

• The vendor (Hogash) must release a patched version (>= 4.22.1) that adds proper capability checks to all AJAX and REST endpoints.
• As a workaround, consider switching to an alternative theme if no patch is forthcoming.

Verification:

• After applying mitigations, test by sending an unauthenticated request to the vulnerable endpoint and confirm a 401 Unauthorized response.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert