CVE-2025-26765

Executive Summary

CVE-2025-26765 is a Missing Authorization vulnerability in the Distance Based Shipping Calculator WordPress plugin by Enituretechnology, affecting versions up to and including 2.0.22. This flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized modification of shipping calculation settings or exposure of sensitive configuration data. As a WordPress plugin vulnerability, it directly impacts the WordPress ecosystem, not the underlying web server software. The CVSS score of 5.4 (Medium) reflects the low complexity and network-based attack vector, though the impact is limited to confidentiality and integrity of the plugin’s data. No public proof-of-concept or exploit code is currently available, and the vendor has not released a patch, leaving all sites using the plugin at risk.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Since no patch is available, site administrators must consider removing or disabling the plugin until a fix is released. The lack of a patch increases supply chain risk, as attackers may target unpatched installations through automated scanning.

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) – Impact confined to the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): None (N) – No denial-of-service impact.

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low-level data exposure and modification. However, in a WordPress context, this could lead to manipulation of shipping costs or disclosure of business logic.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the plugin’s AJAX handlers or REST API endpoints. The plugin likely exposes functions to calculate shipping distances or manage settings without verifying that the requesting user has appropriate permissions (e.g., admin-level access). An unauthenticated attacker can send crafted HTTP requests to these endpoints, bypassing access controls.

Root Cause: The plugin fails to implement capability checks (e.g., current_user_can('manage_options')) before executing sensitive operations. This is a classic CWE-862 (Missing Authorization) issue.

Attack Vector: The attacker sends a POST/GET request to a vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=update_shipping_settings) with malicious parameters. Since no authentication is required, the plugin processes the request.

Impact: An attacker could:

• Modify shipping calculation parameters (e.g., base rates, distance thresholds).
• Expose internal configuration data (e.g., API keys for distance services).
• Potentially leverage the plugin to perform other unauthorized actions.

Vulnerable vs. Patched Code

Since no patch is available, we can only infer the vulnerable pattern. A typical fix would involve adding authorization checks.

Vulnerable Code (Hypothetical):

add_action('wp_ajax_nopriv_update_shipping_settings', 'handle_update');
function handle_update() {
    // No capability check
    update_option('shipping_base_rate', $_POST['rate']);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_nopriv_update_shipping_settings', 'handle_update');
function handle_update() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    update_option('shipping_base_rate', sanitize_text_field($_POST['rate']));
    wp_die();
}

Exploitation & Lab Setup

Red Team (Attack Simulation)

Lab Environment:

• WordPress 6.x with Distance Based Shipping Calculator <= 2.0.22 installed and activated.
• Attacker machine with curl or Burp Suite.

Exploitation Steps:

1. Identify vulnerable endpoints by analyzing the plugin’s JavaScript or PHP files (e.g., look for wp_ajax_nopriv_* hooks).
2. Send a crafted request to trigger the missing authorization:

   curl -X POST 'http://target/wp-admin/admin-ajax.php' \
   -d 'action=update_shipping_settings&rate=0.01&threshold=1000'
   

3. Verify the change by checking the shipping calculator output or plugin settings page.

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

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to the plugin (e.g., update_shipping_settings, get_shipping_data).
• Look for requests from unauthenticated users (no wp_ cookies) to these endpoints.
• Use the Sigma rule below to detect unauthorized access attempts.

Mitigation:

• Disable or remove the plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block requests to known vulnerable endpoints from unauthenticated users.
• Apply the principle of least privilege by restricting access to the plugin’s admin pages via .htaccess or server-level rules.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=update_shipping_settings or similar plugin-specific actions.
  • Requests from IPs not associated with legitimate admin users.
• File IOCs:
  • Modified plugin options in the wp_options table (e.g., shipping_base_rate, distance_threshold).
• Log IOCs:
  • WordPress debug log entries showing unauthorized access attempts to plugin endpoints.

Detection Engineering

YARA Rule

rule Detect_Distance_Shipping_Calculator_Exploit {
    meta:
        description = "Detects exploitation attempts against CVE-2025-26765 in Distance Based Shipping Calculator plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-26765"
    strings:
        $ajax_action = "action=update_shipping_settings"
        $plugin_path = "/wp-content/plugins/distance-based-shipping-calculator/"
        $nopriv_hook = "wp_ajax_nopriv_"
    condition:
        any of them
}

Sigma Rule

title: Unauthorized Access to Distance Based Shipping Calculator Plugin
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated requests to vulnerable plugin endpoints
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=update_shipping_settings'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-26765 - Distance Based Shipping Calculator Missing Authorization Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"admin-ajax.php";
    http_uri;
    content:"action=update_shipping_settings";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin – Deactivate and delete the Distance Based Shipping Calculator plugin from all WordPress installations.
2. Audit for compromise – Check the wp_options table for unauthorized changes to shipping settings.
3. Monitor logs – Review web server and WordPress logs for suspicious AJAX requests.

Long-Term Fix:

• The vendor must release a patched version that adds proper capability checks (e.g., current_user_can('manage_options')) to all AJAX handlers.
• Until then, consider using an alternative shipping calculator plugin with active security maintenance.

Workaround:

• Implement a WAF rule to block unauthenticated requests to admin-ajax.php with plugin-specific actions.
• Use .htaccess to restrict access to the plugin directory:

  <FilesMatch "\.php$">
      Require ip 127.0.0.1
  </FilesMatch>
  

Valters IT
DevSecOps & Cyber Threat Intelligence Division
Report generated for CVE-2025-26765