CVE-2025-58897

Executive Summary

CVE-2025-58897 is a critical PHP Local File Inclusion (LFI) vulnerability in the Axiomthemes Fermentio WordPress theme, affecting all versions up to and including 1.5.0. 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, database credentials, and potentially source code. As a WordPress theme vulnerability, it is exploitable through the WordPress ecosystem without requiring authentication. No patch is currently available, making this a zero-day threat for all active installations.

Supply Chain & Package Security

This vulnerability affects a WordPress theme distributed through the Axiomthemes marketplace and potentially bundled with other products. Since it is a PHP-based theme, the supply chain risk includes:

• Direct exploitation: Attackers can leverage the LFI to read wp-config.php and obtain database credentials.
• Chained attacks: LFI can be combined with file upload vulnerabilities to achieve Remote Code Execution (RCE).
• No patch available: Users must rely on manual mitigation or removal of the theme.

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 (AV:N) – exploitable remotely.
• Attack Complexity: Low (AC:L) – no special conditions required.
• Privileges Required: None (PR:N) – unauthenticated.
• User Interaction: None (UI:N) – no user action needed.
• Scope: Unchanged (S:U) – vulnerability affects only the vulnerable component.
• Confidentiality Impact: High (C:H) – full file read capability.
• Integrity Impact: None (I:N) – no file modification.
• Availability Impact: None (A:N) – no denial of service.

Threat Level: High. The lack of authentication and low complexity make this a prime target for automated scanning and exploitation.

Deep Dive & Mechanics

The vulnerability exists in the Fermentio theme's PHP code, likely within a template or plugin file that uses include() or require() with user-supplied input. The improper control of the filename allows an attacker to traverse directories using ../ sequences and read arbitrary files.

Root Cause: The theme fails to sanitize or validate the $_GET, $_POST, or $_COOKIE parameter used in a PHP include statement. For example, a vulnerable code snippet might look like:

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

This allows an attacker to supply a path like ../../../../etc/passwd to read system files.

Exploitation Flow:

1. Attacker identifies a parameter (e.g., page, template, file) in the theme's URL.
2. Attacker sends a request with a path traversal payload.
3. The server includes the specified file, outputting its contents in the HTTP response.

WordPress Context: Since this is a WordPress theme, the vulnerable parameter is likely part of a custom page template or shortcode. The attack does not require WordPress admin credentials.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is presumed to be present in all versions <= 1.5.0. A hypothetical patched version would implement proper input validation and path restriction.

Vulnerable Code (Example):

// In a theme template file (e.g., page.php)
$file = $_GET['file'];
include( get_template_directory() . '/includes/' . $file . '.php' );

Patched Code (Hypothetical):

// Patched version with whitelist and path sanitization
$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 traversal and a whitelist to restrict allowed files.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress installation with Fermentio theme version <= 1.5.0.
• Knowledge of the vulnerable parameter (e.g., ?file=).

Exploit Steps:

1. Identify the vulnerable endpoint. Common patterns include:
   • http://target/wp-content/themes/fermentio/page.php?file=...
   • http://target/?page_id=...&template=...
2. Use path traversal to read sensitive files:
   • http://target/?file=../../../../etc/passwd
   • http://target/?file=../../../../wp-config.php
3. For Windows servers, use:
   • http://target/?file=../../../../windows/win.ini

Proof of Concept (PoC):

curl -v "http://target/wp-content/themes/fermentio/page.php?file=../../../../etc/passwd"

Expected Output: The contents of /etc/passwd will be displayed in the response body.

Blue Team (Defensive)

Detection:

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

Hunting Query:

SELECT * FROM wp_logs WHERE request_uri LIKE '%../%' AND request_uri LIKE '%fermentio%';

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests containing ../ or %2e%2e%2f in the query string.
  • Requests to /wp-content/themes/fermentio/ with suspicious parameters.
  • Outbound connections from the web server to unknown IPs (if chained with RCE).

• File IOCs:

  • Unexpected files in /tmp/ or web-accessible directories.
  • Modified .htaccess files (if used for persistence).

• Log IOCs:

  • Web server logs showing 404 or 200 responses to path traversal attempts.
  • PHP error logs with include() failures.

Detection Engineering

YARA Rule

rule CVE_2025_58897_LFI_Detection {
    meta:
        description = "Detects path traversal attempts targeting Fermentio theme"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58897"
    strings:
        $path_traversal = /(\.\.\/|%2e%2e%2f|%252e%252e%252f)/
        $theme_path = /fermentio/i
    condition:
        $path_traversal and $theme_path
}

Sigma Rule

title: CVE-2025-58897 Fermentio LFI Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects path traversal attempts against Fermentio WordPress theme
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - '../'
            - '%2e%2e%2f'
            - '..\\'
        cs-uri-stem|contains: '/wp-content/themes/fermentio/'
    condition: selection
falsepositives:
    - Legitimate use of relative paths in custom code
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-58897 Fermentio LFI Attempt"; flow:to_server,established; content:"/wp-content/themes/fermentio/"; http_uri; content:"../"; http_uri; distance:0; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the theme: Switch to a default WordPress theme (e.g., Twenty Twenty-Four) until a patch is available.
2. Web Application Firewall (WAF): Deploy rules to block path traversal patterns in URI parameters.
3. File Permissions: Ensure wp-config.php and other sensitive files are not readable by the web server user (e.g., chmod 600).

Long-term Fix:

• Monitor the Axiomthemes website for an official patch.
• Apply the patch immediately when released.
• Consider replacing the theme with a more secure alternative.

Workaround:

• If the theme cannot be disabled, add the following to .htaccess to block path traversal:

RewriteEngine On
RewriteCond %{QUERY_STRING} (\.\./|%2e%2e%2f) [NC]
RewriteRule ^ - [F,L]

Valters IT – Securing digital frontiers, one CVE at a time.