CVE-2025-67981

Executive Summary

CVE-2025-67981 is a critical PHP Local File Inclusion (LFI) vulnerability discovered in the Besa WordPress theme developed by Thembay. The flaw resides in 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 configuration files, database credentials, or source code. The vulnerability affects all versions of Besa up to and including 2.3.15. No official patch has been released at this time, and no public proof-of-concept (PoC) code is available. The CVSS score of 8.1 (High) reflects the ease of exploitation and potential for significant data exposure.

Supply Chain & Package Security

This vulnerability is specific to the WordPress ecosystem and the Besa theme. It is not related to NPM, PyPI, Go, or Ruby packages. However, organizations using this theme should treat it as a supply chain risk, as the theme is a third-party component integrated into WordPress sites. The lack of a patch increases the risk of compromise.

CVSS Breakdown & Threat Level

• CVSS Score: 8.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

The threat level is High due to the low complexity and no authentication requirement. An attacker can exploit this remotely to read sensitive files, potentially leading to further compromise.

Deep Dive & Mechanics

The vulnerability is a PHP Local File Inclusion (LFI) caused by improper control of a filename used in an include or require statement. In the Besa theme, a parameter (likely page, template, or similar) is passed to a PHP function without proper sanitization. An attacker can manipulate this parameter to include arbitrary files from the server's filesystem.

Example vulnerable code pattern:

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

An attacker could exploit this by sending a request like:

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

The %00 null byte (if PHP version < 5.3.4) or path traversal can allow reading files outside the intended directory. Since the vulnerability is in a WordPress theme, it is accessible via the web root.

Vulnerable vs. Patched Code

Vulnerable Code (Besa <= 2.3.15):

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

Patched Code (Hypothetical):

// Properly sanitize and restrict path
$allowed_templates = array('home', 'single', 'page');
$template = $_GET['template'];
if (in_array($template, $allowed_templates)) {
    include( get_template_directory() . '/templates/' . $template . '.php' );
} else {
    // Default template
    include( get_template_directory() . '/templates/page.php' );
}

The patched version uses a whitelist approach to restrict included files to a predefined set, preventing arbitrary file inclusion.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install WordPress with the Besa theme (version 2.3.15 or earlier).
2. Ensure the server is accessible from the attacker's machine.

Exploitation Steps:

1. Identify the vulnerable parameter (e.g., template, page, file).
2. Craft a request to include a sensitive file:

   GET /wp-content/themes/besa/index.php?template=../../../../etc/passwd HTTP/1.1
   Host: target.com
   

3. If the server returns the contents of /etc/passwd, the vulnerability is confirmed.

Note: No public exploit code is available, but the technique is standard LFI.

Blue Team

Detection:

• Monitor web server logs for suspicious path traversal patterns (e.g., ../, %2e%2e%2f).
• Look for requests to Besa theme files with unexpected parameters.
• Use WAF rules to block LFI attempts.

Hunting:

• Search for requests containing template=, page=, or file= parameters in the context of the Besa theme.
• Correlate with file read attempts (e.g., /etc/passwd, /wp-config.php).

Indicators of Compromise (IOCs)

• File Paths: /etc/passwd, /etc/shadow, /wp-config.php, /proc/self/environ
• URL Patterns: ?template=../../, ?page=../../, ?file=../../
• Log Entries: HTTP requests with ../ sequences in the query string targeting Besa theme files.
• Response Content: Unauthorized disclosure of system files or WordPress configuration.

Detection Engineering

YARA Rule

rule CVE_2025_67981_LFI_Detection {
    meta:
        description = "Detects LFI attempts targeting Besa theme CVE-2025-67981"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-67981"
    strings:
        $path_traversal = /(\.\.\/|\.\.\\|%2e%2e%2f|%2e%2e%5c)/
        $besa_theme = /wp-content\/themes\/besa/i
        $sensitive_file = /(etc\/passwd|etc\/shadow|wp-config\.php|proc\/self\/environ)/
    condition:
        $besa_theme and $path_traversal and $sensitive_file
}

Sigma Rule

title: CVE-2025-67981 LFI Attempt on Besa Theme
id: 8a3f7c2e-1b4d-4e9f-8c6a-5d2b1e0f3a7c
status: experimental
description: Detects path traversal attempts in HTTP requests targeting the Besa WordPress theme.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-uri-query|contains:
            - 'template=..'
            - 'page=..'
            - 'file=..'
        cs-uri-stem|contains: '/wp-content/themes/besa/'
    condition: selection
falsepositives:
    - Legitimate use of similar parameters (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-67981 LFI Attempt on Besa Theme"; flow:to_server,established; content:"/wp-content/themes/besa/"; http_uri; content:"../"; http_uri; distance:0; within:10; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable or remove the Besa theme until a patch is available.
2. Workaround: Implement a Web Application Firewall (WAF) rule to block path traversal patterns in requests to the Besa theme.
3. Code Fix: Apply input validation and whitelisting for any file inclusion parameters.
4. Monitoring: Enable detailed logging for web server and review logs for suspicious activity.
5. Update: Monitor Thembay's official channels for a patched version and apply it immediately.

Valters IT
Securing Digital Frontiers