CVE-2024-53806

Executive Summary

CVE-2024-53806 is a Missing Authorization vulnerability in the Maspik – Spam Blacklist WordPress plugin, affecting versions up to and including 2.2.7. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized access to plugin settings or data. The vulnerability is classified as a WordPress ecosystem issue, not related to Apache or Nginx. With a CVSS score of 5.4 (Medium), it poses a moderate risk, primarily impacting confidentiality and integrity. No public proof-of-concept (PoC) or exploit code is currently available, and the patch status remains unknown.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor for updates from the vendor (Yonifre) and apply patches as soon as they become available. Since the plugin is part of the WordPress ecosystem, supply chain risks include potential compromise of the plugin update mechanism or malicious code injection in future versions.

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

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low confidentiality and integrity loss.

Deep Dive & Mechanics

The vulnerability resides in the Maspik – Spam Blacklist plugin, which is designed to block spam in contact forms. The issue is a Missing Authorization (CWE-862) flaw, meaning the plugin fails to properly verify that a user has the necessary permissions before performing sensitive actions. Specifically, the plugin does not enforce access control checks on certain administrative functions or AJAX endpoints, allowing unauthenticated attackers to:

• Access or modify plugin settings.
• View or manipulate the spam blacklist.
• Potentially bypass spam protection mechanisms.

The vulnerability is exploitable via crafted HTTP requests to vulnerable endpoints. Since the plugin is widely used in WordPress sites, the attack surface is significant.

Vulnerable vs. Patched Code

No patched version is currently available. The vulnerable code likely lacks permission checks in functions handling AJAX requests or admin pages. A typical fix would involve adding current_user_can() checks or nonce verification to ensure only authorized users can perform sensitive actions.

Vulnerable Code Example (Hypothetical):

add_action('wp_ajax_maspik_update_blacklist', 'maspik_update_blacklist');
function maspik_update_blacklist() {
    // No permission check
    update_option('maspik_blacklist', $_POST['blacklist']);
}

Patched Code Example (Hypothetical):

add_action('wp_ajax_maspik_update_blacklist', 'maspik_update_blacklist');
function maspik_update_blacklist() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized');
    }
    check_ajax_referer('maspik_nonce', 'nonce');
    update_option('maspik_blacklist', $_POST['blacklist']);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with Maspik plugin version <= 2.2.7.
• Network access to the target.

Exploitation Steps:

1. Identify vulnerable endpoints (e.g., /wp-admin/admin-ajax.php with action maspik_*).
2. Send a crafted POST request without authentication:

   curl -X POST http://target/wp-admin/admin-ajax.php \
     -d 'action=maspik_update_blacklist&blacklist=malicious_entry'
   

3. Verify unauthorized access by checking if the blacklist was modified.

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

Blue Team

Detection & Prevention:

• Monitor for unusual AJAX requests to /wp-admin/admin-ajax.php with actions related to Maspik.
• Implement Web Application Firewall (WAF) rules to block unauthenticated requests to sensitive plugin endpoints.
• Regularly update the plugin and apply patches when available.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with parameters like action=maspik_* from unauthenticated sources.
  • Unusual entries in the wp_options table under maspik_blacklist or similar options.
• File IOCs:
  • Modified plugin files in /wp-content/plugins/maspik/ (e.g., maspik.php or AJAX handlers).
• Log IOCs:
  • WordPress debug logs showing unauthorized access attempts to admin AJAX actions.

Detection Engineering

YARA Rule

rule Detect_Maspik_Missing_Auth {
    meta:
        description = "Detects exploitation attempts for CVE-2024-53806 in Maspik plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-53806"
    strings:
        $ajax_action = "maspik_" ascii wide nocase
        $admin_ajax = "admin-ajax.php" ascii wide nocase
    condition:
        $ajax_action and $admin_ajax
}

Sigma Rule

title: Maspik Missing Authorization Exploitation Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects unauthenticated POST requests to Maspik AJAX actions
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: 'action=maspik_'
    condition: selection
falsepositives:
    - Legitimate admin actions (if authenticated)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-53806 Maspik Missing Authorization Attempt"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=maspik_"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable the Maspik plugin until a patch is available.
• Short-term: Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to /wp-admin/admin-ajax.php with action=maspik_* parameters.
• Long-term: Monitor the vendor's website for updates and apply the patch as soon as it is released. Consider using a security plugin like Wordfence to add additional access control layers.
• Workaround: If the plugin is essential, restrict access to /wp-admin/ via .htaccess or IP whitelisting.

Valters IT
DevSecOps & Cyber Threat Intelligence