CVE-2025-52729

Executive Summary

CVE-2025-52729 is a critical PHP Local File Inclusion (LFI) vulnerability discovered in the Diza WordPress theme by Thembay, affecting versions up to and including 1.3.9. The vulnerability stems from improper control of filenames used in PHP include/require statements, allowing an unauthenticated attacker to include arbitrary local files from the server. This can lead to sensitive information disclosure, such as reading /etc/passwd, database configuration files, or WordPress wp-config.php. The CVSS score of 8.1 (High) reflects the ease of exploitation (network-based, low complexity, no privileges required) and the high impact on confidentiality. No public proof-of-concept (PoC) or patch is currently available, making this a zero-day threat for unpatched installations.

WordPress Ecosystem Context

This vulnerability is specific to the Diza WordPress theme and is not related to Apache or Nginx server misconfigurations. The attack vector relies on the theme's PHP code mishandling user-supplied input in file inclusion functions.

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 remains the same.
• Confidentiality (C): High (H) – Full file read access.
• Integrity (I): None (N) – No file modification.
• Availability (A): None (N) – No denial of service.

Threat Level: High. The combination of remote, unauthenticated access with low complexity and high confidentiality impact makes this a priority for patching.

Deep Dive & Mechanics

The vulnerability exists in the Diza theme's PHP code, likely in a function that dynamically includes template files or language files based on user input (e.g., via GET/POST parameters). The improper control of the filename allows path traversal sequences (e.g., ../../) to escape the intended directory and include arbitrary files from the filesystem.

Root Cause: The theme uses a function like include($_GET['file'] . '.php') or similar without sanitizing the input for directory traversal characters. An attacker can supply a payload such as ?file=../../../etc/passwd%00 to null-terminate the string and include /etc/passwd.

Attack Flow:

1. Attacker identifies a vulnerable endpoint (e.g., wp-content/themes/diza/template.php?file=...).
2. Attacker crafts a request with path traversal and null byte injection (if PHP < 5.3.4) or simply uses ../ sequences.
3. The server includes the specified file, outputting its contents in the HTTP response.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is hypothesized based on common LFI vulnerabilities in WordPress themes.

Vulnerable Code (Hypothetical):

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

Patched Code (Hypothetical):

<?php
$allowed_files = array('header', 'footer', 'sidebar');
$file = $_GET['file'];
if (in_array($file, $allowed_files)) {
    include('templates/' . $file . '.php');
} else {
    // Handle error
}
?>

The patched version uses a whitelist approach to restrict inclusion to only predefined files.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

• Install WordPress with Diza theme version 1.3.9 on a local server (e.g., XAMPP, LAMP).
• Ensure the vulnerable endpoint is accessible (e.g., http://localhost/wp-content/themes/diza/template.php).

Exploitation Steps:

1. Identify the vulnerable parameter (e.g., file).
2. Use path traversal to read sensitive files:

   http://localhost/wp-content/themes/diza/template.php?file=../../../wp-config.php
   

3. If PHP version is < 5.3.4, use null byte injection:

   http://localhost/wp-content/themes/diza/template.php?file=../../../etc/passwd%00
   

4. For log poisoning (if applicable), inject PHP code into server logs (e.g., via User-Agent) and include the log file.

Example cURL Command:

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

Blue Team (Defensive)

Detection:

• Monitor web server logs for path traversal patterns (e.g., ../, %00).
• Look for requests to theme files with suspicious parameters.
• Use WAF rules to block directory traversal sequences.

Hunting:

• Search for requests containing file= parameter in the Diza theme directory.
• Check for unusual file inclusion attempts in PHP error logs.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests with ../ or %00 in parameters targeting wp-content/themes/diza/.
  • Unusual User-Agent strings containing PHP code (for log poisoning).
• File System IOCs:
  • Unexpected files in /tmp/ or web root with .php extension.
  • Modified server logs with embedded PHP code.
• Log IOCs:
  • Apache/Nginx access logs showing path traversal attempts.
  • PHP error logs with "include()" warnings.

Detection Engineering

YARA Rule

rule CVE_2025_52729_LFI_Diza {
    meta:
        description = "Detects path traversal attempts targeting Diza theme LFI"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-52729"
    strings:
        $path_traversal = /\.\.\// nocase
        $null_byte = /%00/ nocase
        $diza_param = /file=/ nocase
        $diza_path = /wp-content\/themes\/diza/ nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-52729 Diza Theme LFI Detection
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects path traversal attempts in Diza theme requests
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - 'file=../'
            - 'file=%00'
            - 'file=..%2f'
        cs-uri-stem|contains: '/wp-content/themes/diza/'
    condition: selection
falsepositives:
    - Legitimate use of relative paths in admin functions (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-52729 Diza Theme LFI Attempt"; flow:to_server,established; content:"/wp-content/themes/diza/"; http_uri; content:"file="; http_uri; pcre:"/file=(\.\.\/|%00)/Ui"; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the Diza theme and switch to a default WordPress theme (e.g., Twenty Twenty-Four) until a patch is available.
2. Implement a Web Application Firewall (WAF) rule to block path traversal patterns in requests to the Diza theme directory.
3. Restrict file permissions on sensitive files (e.g., wp-config.php should be readable only by the web server user).

Long-term Fix:

• Contact Thembay for an official patch or update to a patched version.
• If custom development is possible, apply input validation and whitelisting to the vulnerable include statements.

Workaround:

• Add the following to .htaccess to block direct access to theme files:

  <FilesMatch "\.php$">
      Order Deny,Allow
      Deny from all
  </FilesMatch>
  

  (Note: This may break legitimate theme functionality.)

Valters IT
Securing Digital Frontiers