CVE-2025-67530

Executive Summary

CVE-2025-67530 is a critical PHP Local File Inclusion (LFI) vulnerability discovered in the Besa WordPress theme developed by Thembay. The vulnerability stems from improper control of a filename used in a PHP include or require statement, allowing an unauthenticated attacker to include arbitrary local files from the server. This can lead to sensitive information disclosure, such as reading configuration files containing database credentials, source code, or other system files. The vulnerability affects all versions of Besa up to and including 2.3.15. No patch is currently available, and no public proof-of-concept exploit has been released. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the risk remains high due to the potential impact.

Supply Chain & Package Security

This vulnerability is specific to the WordPress ecosystem and the Besa theme. It is not an NPM, PyPI, Go, or Ruby package. The theme is distributed via WordPress theme repositories and potentially third-party marketplaces. Users should verify the integrity of their theme files and ensure they are obtained from trusted sources. The lack of a patch means that users must rely on alternative mitigations, such as web application firewall (WAF) rules or disabling the vulnerable functionality.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Base Score: 7.5 (HIGH)
• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) – No special conditions or complex attack sequences are required.
• Privileges Required (PR): None (N) – No authentication is needed to exploit the vulnerability.
• User Interaction (UI): None (N) – The victim does not need to perform any action.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – An attacker can read sensitive files, leading to complete information disclosure.
• Integrity (I): None (N) – The vulnerability does not allow modification of data.
• Availability (A): None (N) – The vulnerability does not affect system availability.

Threat Level: HIGH. The ease of exploitation and potential for sensitive data exposure make this a critical concern for all sites using the Besa theme.

Deep Dive & Mechanics

The vulnerability is a classic PHP Local File Inclusion (LFI) issue. It occurs when a PHP application uses a user-supplied input to construct a file path for an include or require statement without proper sanitization or validation. In the context of the Besa theme, this likely involves a parameter (e.g., page, template, or file) that is passed to a PHP function like include($_GET['file'] . '.php'). An attacker can manipulate this parameter to include arbitrary files from the server.

Example vulnerable code pattern:

<?php
$file = $_GET['file'];
include($file . '.php');
?>

An attacker could exploit this by sending a request like:

http://target.com/wp-content/themes/besa/vulnerable-page.php?file=../../../../etc/passwd%00

The %00 (null byte) is used to terminate the string, effectively removing the .php extension appended by the code. This allows the inclusion of files like /etc/passwd.

WordPress Context: Since this is a WordPress theme, the vulnerable code is likely within a template file or a custom page handler. The theme may use include or require to load template parts based on user input, such as a page_id or template parameter.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable pattern and what a hypothetical patch would look like.

Vulnerable Code (Hypothetical):

<?php
// vulnerable.php
$template = $_GET['template'];
include('templates/' . $template . '.php');
?>

Patched Code (Hypothetical):

<?php
// patched.php
$allowed_templates = ['home', 'single', 'page', 'archive'];
$template = $_GET['template'];
if (in_array($template, $allowed_templates)) {
    include('templates/' . $template . '.php');
} else {
    // Handle error or use default template
    include('templates/default.php');
}
?>

The patch uses a whitelist approach, only allowing predefined template names. Alternatively, the patch could use realpath() to resolve the path and ensure it is within the expected directory, or use basename() to strip directory traversal sequences.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress instance with Besa theme version <= 2.3.15.
• Knowledge of the vulnerable parameter (e.g., file, template, page).

Exploitation Steps:

1. Identify the vulnerable endpoint. This could be a page like /wp-content/themes/besa/vulnerable-page.php or a WordPress page with a custom template.
2. Use a web browser or tool like curl to send a crafted request:

   curl "http://target.com/wp-content/themes/besa/vulnerable-page.php?file=../../../../etc/passwd%00"
   

3. If successful, the contents of /etc/passwd will be displayed in the response.
4. For more advanced exploitation, attempt to include PHP files to achieve Remote Code Execution (RCE) via log poisoning or other techniques.

Lab Setup:

• Use a local WordPress installation with the Besa theme.
• Create a simple PHP file that simulates the vulnerability:

  <?php
  // test-lfi.php
  $file = $_GET['file'];
  include($file . '.php');
  ?>
  

• Place this file in the theme directory and access it via the browser.

Blue Team (Defensive)

Detection:

• Monitor web server logs for requests containing directory traversal patterns (e.g., ../, %2e%2e%2f).
• Look for requests to theme files with suspicious parameters.
• Use a WAF to block requests with ../ or null bytes (%00).

Mitigation:

• Disable the vulnerable functionality if possible.
• Apply virtual patching via WAF rules.
• Restrict file permissions to prevent reading sensitive files.
• Use a security plugin that monitors file inclusion attempts.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests containing ../ or %2e%2e%2f in parameters.
  • Requests to /wp-content/themes/besa/ with suspicious query strings.
  • Responses containing contents of system files like /etc/passwd, /etc/shadow, or wp-config.php.

• File System IOCs:

  • Unexpected inclusion of files outside the web root.
  • Modified or new files in the theme directory (if RCE is achieved).

• Log IOCs:

  • Web server access logs showing 404 or 200 responses for LFI attempts.
  • Error logs showing include() failures or warnings.

Detection Engineering

YARA Rule

rule CVE_2025_67530_LFI_Attempt {
    meta:
        description = "Detects LFI attempts targeting CVE-2025-67530 in Besa theme"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-67530"
    strings:
        $lfi_pattern1 = /file=\.\.\/\.\.\// nocase
        $lfi_pattern2 = /template=\.\.\/\.\.\// nocase
        $lfi_pattern3 = /%00/ nocase
        $lfi_pattern4 = /\.\.\/\.\.\/\.\.\/\.\.\/etc\/passwd/ nocase
    condition:
        any of ($lfi_pattern*)
}

Sigma Rule

title: CVE-2025-67530 LFI Attempt Detection
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests with directory traversal patterns targeting Besa theme
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-uri-query|contains:
            - 'file=../'
            - 'template=../'
            - '%00'
            - '/etc/passwd'
    condition: selection
falsepositives:
    - Legitimate use of relative paths in some applications
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-67530 LFI Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/wp-content/themes/besa/"; http_uri; content:"../"; http_uri; content:"%00"; http_uri; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable functionality: If the vulnerable parameter is not essential, remove or comment out the code that handles it.
2. Apply virtual patching: Use a WAF (e.g., ModSecurity, Cloudflare) to block requests containing directory traversal patterns.
3. Restrict file permissions: Ensure that sensitive files (e.g., wp-config.php, /etc/passwd) are not readable by the web server user.
4. Monitor logs: Actively monitor web server logs for LFI attempts.

Long-term Solutions:

1. Update the theme: Once a patch is released, update to the latest version immediately.
2. Code review: Conduct a security audit of the theme to identify and fix similar vulnerabilities.
3. Use a security plugin: Install a WordPress security plugin that provides file integrity monitoring and LFI protection.
4. Implement input validation: Ensure all user inputs are validated and sanitized before being used in file operations.

Workaround:

• If the vulnerable parameter is used for template loading, modify the code to use a whitelist of allowed templates.

Valters IT
Securing Digital Frontiers