CVE-2025-22319

Executive Summary

CVE-2025-22319 is a Missing Authorization vulnerability in the DearHive Social Media Share Buttons | MashShare WordPress plugin, affecting all versions up to and including 4.0.47. This flaw allows unauthenticated attackers to access or modify certain plugin settings or data without proper permission checks, leading to unauthorized information disclosure or configuration changes. The vulnerability is classified as Medium severity (CVSS 4.3) and currently has no known public exploit or patch. As a WordPress plugin issue, this is a supply chain risk for any site using the MashShare plugin.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. The plugin is not an NPM, PyPI, Go, or Ruby package, but it is a critical component of the WordPress ecosystem. Organizations using this plugin should treat it as a third-party dependency and monitor for updates from the vendor or consider replacing it.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

Threat Level: Low to Medium. The vulnerability allows unauthorized access to non-critical data or settings, but no public exploit exists. However, the lack of a patch increases risk over time.

Deep Dive & Mechanics

The vulnerability stems from a missing authorization check in the MashShare plugin's REST API endpoints or AJAX handlers. WordPress plugins often expose actions via admin-ajax.php or custom REST routes. In this case, the plugin fails to verify that the current user has the required capabilities (e.g., manage_options) before processing requests. This allows any unauthenticated user to:

• Retrieve plugin configuration (e.g., API keys, social network settings)
• Modify non-sensitive settings (e.g., button styles, share counts)
• Potentially trigger other actions that could lead to further exploitation

The vulnerable code likely resides in a function hooked to wp_ajax_* or wp_ajax_nopriv_* actions without a current_user_can() check. For example:

add_action('wp_ajax_mashshare_update_settings', 'mashshare_update_settings');
add_action('wp_ajax_nopriv_mashshare_update_settings', 'mashshare_update_settings');
function mashshare_update_settings() {
    // Missing capability check
    update_option('mashshare_settings', $_POST['settings']);
}

Vulnerable vs. Patched Code

Vulnerable Code (<= 4.0.47):

// No capability check
add_action('wp_ajax_mashshare_get_config', 'mashshare_get_config');
add_action('wp_ajax_nopriv_mashshare_get_config', 'mashshare_get_config');
function mashshare_get_config() {
    $config = get_option('mashshare_config');
    wp_send_json($config);
}

Patched Code (Hypothetical):

add_action('wp_ajax_mashshare_get_config', 'mashshare_get_config');
// Remove nopriv hook to require authentication
function mashshare_get_config() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    $config = get_option('mashshare_config');
    wp_send_json($config);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with MashShare <= 4.0.47 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=mashshare_get_config).
2. Send a crafted request to retrieve configuration data.

curl -X POST "http://target.com/wp-admin/admin-ajax.php" \
  -d "action=mashshare_get_config"

3. If the endpoint returns sensitive data (e.g., API keys), the attacker can use them for further attacks.

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

Blue Team

Detection:

• Monitor for unusual requests to /wp-admin/admin-ajax.php with action=mashshare_* parameters from unauthenticated sources.
• Look for spikes in 403 errors if a WAF blocks such requests.

Hunting:

• Search logs for POST /wp-admin/admin-ajax.php with body containing action=mashshare.
• Check for unauthorized access to plugin settings via audit logs.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=mashshare_get_config or similar.
  • Unusual outbound connections from the WordPress server to external IPs (if API keys are exfiltrated).
• File:
  • Modified plugin files in /wp-content/plugins/mashsharer/ (if attacker uploads malicious code).
• Log:
  • WordPress debug log entries showing mashshare_* actions without authentication.

Detection Engineering

YARA Rule

rule CVE_2025_22319_MashShare_Missing_Auth {
    meta:
        description = "Detects MashShare plugin files with missing authorization checks"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-22319"
    strings:
        $ajax_hook = /add_action\(['\"]wp_ajax_nopriv_mashshare_/
        $missing_cap = !/current_user_can\(/
    condition:
        $ajax_hook and $missing_cap
}

Sigma Rule

title: CVE-2025-22319 MashShare Missing Authorization
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated access to MashShare plugin AJAX endpoints
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=mashshare_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-22319 MashShare Missing Authorization Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-ajax.php";
    http_uri;
    content:"action=mashshare_";
    http_client_body;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the MashShare plugin until a patch is available.
2. Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to admin-ajax.php with action=mashshare_*.
3. Monitor logs for exploitation attempts.

Long-term:

• Replace the plugin with an alternative (e.g., "Social Warfare" or "AddToAny").
• If the vendor releases a patch, update to the latest version immediately.
• Conduct a security audit of all WordPress plugins for similar missing authorization issues.

Workaround:

• Add a custom function to your 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'], 'mashshare_') === 0) {
            if (!is_user_logged_in()) {
                wp_die('Unauthorized', 403);
            }
        }
    }
});

Valters IT
Securing Digital Frontiers