CVE-2025-30934

Executive Summary

CVE-2025-30934 is a Missing Authorization vulnerability in the OLIVESYSTEM 診断ジェネレータ作成プラグイン (os-diagnosis-generator) for WordPress. This flaw allows unauthenticated attackers to access functionality that should be constrained by Access Control Lists (ACLs). The vulnerability affects all versions up to and including 1.4.16. With a CVSS score of 5.3 (Medium), the primary impact is on confidentiality, as an attacker can bypass authorization checks to read sensitive data or perform unauthorized actions. No public exploit code or proof-of-concept is currently available, and no patch has been released by the vendor.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Users who have installed the plugin directly from the WordPress dashboard or via manual upload are affected. There is no known compromise of the plugin’s supply chain, but the lack of a patch increases the risk of supply chain attacks if the plugin is used in production environments.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 5.3 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: Low (C:L)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low confidentiality loss. However, in the context of WordPress, this could expose sensitive diagnostic data or allow unauthorized access to administrative functions.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the os-diagnosis-generator plugin. The plugin likely registers AJAX actions or REST API endpoints that are intended for authenticated users (e.g., administrators) but fails to verify user capabilities before executing sensitive operations. An attacker can directly call these endpoints without a valid session or nonce, bypassing the intended ACLs.

Root Cause: The plugin does not implement current_user_can() or similar capability checks in its callback functions for AJAX or REST API hooks. For example, a function hooked to wp_ajax_* might be incorrectly registered as wp_ajax_nopriv_*, allowing unauthenticated access.

Attack Vector: An unauthenticated attacker sends crafted HTTP requests to the vulnerable endpoints, triggering actions such as reading diagnostic logs, modifying plugin settings, or accessing internal data.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described below. A patched version would include proper capability checks.

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_os_diagnosis_get_data', 'os_diagnosis_get_data');
function os_diagnosis_get_data() {
    // No capability check
    $data = get_option('os_diagnosis_data');
    wp_send_json_success($data);
}

Patched Code (Hypothetical):

add_action('wp_ajax_os_diagnosis_get_data', 'os_diagnosis_get_data');
function os_diagnosis_get_data() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    $data = get_option('os_diagnosis_data');
    wp_send_json_success($data);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress instance with the vulnerable plugin (<=1.4.16) installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify the vulnerable endpoint. Common patterns include /wp-admin/admin-ajax.php?action=os_diagnosis_get_data or a custom REST route.
2. Send a direct HTTP request to the endpoint without any authentication cookies.
3. Observe the response containing sensitive data.

Example using cURL:

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

Expected Output:

{"success":true,"data":{"diagnostic_log":"...","config":"..."}}

Blue Team

Detection:

• Monitor for requests to admin-ajax.php with suspicious action parameters related to os_diagnosis.
• Look for requests without a valid X-WP-Nonce header or WordPress nonce cookie.

Hunting Query (Splunk):

index=web sourcetype=access_combined
| search uri="/wp-admin/admin-ajax.php" form_data=*os_diagnosis*
| eval auth=if(match(cookie, "wordpress_logged_in"), "authenticated", "unauthenticated")
| where auth="unauthenticated"
| stats count by src_ip, uri, form_data

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=os_diagnosis_* parameters.
  • Absence of wordpress_logged_in cookie in such requests.
• File:
  • Presence of the plugin directory /wp-content/plugins/os-diagnosis-generator/.
  • Plugin version file showing 1.4.16 or lower.
• Log:
  • WordPress debug log entries showing unauthorized access attempts to plugin-specific actions.

Detection Engineering

YARA Rule

rule CVE_2025_30934_WordPress_Plugin {
    meta:
        description = "Detects vulnerable os-diagnosis-generator plugin files"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-30934"
    strings:
        $vuln_func = "wp_ajax_nopriv_os_diagnosis" nocase
        $no_cap = "current_user_can" nocase
    condition:
        $vuln_func and not $no_cap
}

Sigma Rule

title: CVE-2025-30934 - Unauthenticated Access to os-diagnosis-generator
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated requests to vulnerable os-diagnosis-generator AJAX endpoints
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=os_diagnosis'
    filter:
        cs-uri-query|contains: 'os_diagnosis_nonce'
    condition: selection and not filter
falsepositives:
    - Legitimate authenticated requests with nonce
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-30934 - Unauthenticated os-diagnosis-generator Access"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=os_diagnosis"; http_client_body; pcre:"/action=os_diagnosis_[a-z_]+/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not critical to operations.
2. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action parameters starting with os_diagnosis_ from unauthenticated users.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• The vendor must release a patched version that adds proper capability checks using current_user_can() or wp_verify_nonce().
• Until then, consider forking the plugin and applying the patch manually.

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 && !is_user_logged_in()) {
        $action = $_REQUEST['action'] ?? '';
        if (strpos($action, 'os_diagnosis_') === 0) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT
DevSecOps & Cyber Threat Intelligence