CVE-2019-25480: ARMBot Path Traversal Vulnerability

CVE-2019-25480 Overview

CVE-2019-25480 is an unrestricted file upload vulnerability affecting ARMBot's upload.php component. This vulnerability allows unauthenticated attackers to upload arbitrary files by manipulating the file parameter with path traversal sequences. Attackers can upload PHP files with traversal payloads such as ../public_html/ to write executable code to the web root and achieve remote code execution.

Critical Impact

Unauthenticated remote attackers can achieve arbitrary code execution on vulnerable ARMBot installations by uploading malicious PHP files directly to the web root through path traversal exploitation.

Affected Products

• ARMBot (all versions with vulnerable upload.php)

Discovery Timeline

• 2026-03-11 - CVE-2019-25480 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2019-25480

Vulnerability Analysis

This vulnerability combines two dangerous security weaknesses: unrestricted file upload and path traversal (CWE-22). The vulnerable upload.php endpoint in ARMBot fails to properly validate both the type of files being uploaded and the destination path where files are written.

The core issue lies in insufficient input validation of the file parameter. When an attacker crafts a malicious request containing path traversal sequences (such as ../), the application processes these sequences without sanitization, allowing the attacker to navigate out of the intended upload directory. By chaining this with the ability to upload files with arbitrary extensions, attackers can place PHP web shells or other malicious scripts directly into the web-accessible document root.

Since the vulnerability requires no authentication, any network-accessible ARMBot installation is at risk. Successful exploitation results in complete compromise of the web server, allowing attackers to execute arbitrary commands with the privileges of the web server process.

Root Cause

The root cause of this vulnerability is improper input validation in the upload.php script. The application fails to:

1. Sanitize path traversal sequences (../, ..\\) from the file parameter
2. Validate or restrict file extensions to prevent executable file uploads
3. Implement authentication checks before processing file upload requests
4. Restrict the upload destination to a designated, non-executable directory

This combination of missing security controls allows attackers to bypass intended restrictions and write malicious files anywhere within the filesystem that the web server process has write permissions.

Attack Vector

The attack is conducted over the network and requires no authentication or user interaction. An attacker sends a specially crafted HTTP request to the vulnerable upload.php endpoint, including path traversal sequences in the file parameter to specify a target location such as the web root directory. The uploaded file, typically a PHP web shell, is written to the specified location. Once the malicious file is in the web root, the attacker can access it via HTTP and execute arbitrary commands on the server.

For detailed technical information about the exploitation mechanism, refer to the Exploit-DB #47209 entry and the VulnCheck Advisory.

Detection Methods for CVE-2019-25480

Indicators of Compromise

• Unexpected PHP files appearing in the web root or public_html directory
• Web server access logs showing requests to upload.php with path traversal patterns (../)
• Newly created files with web shell signatures or suspicious PHP code
• Unusual outbound network connections originating from the web server process

Detection Strategies

• Monitor HTTP request logs for requests containing ../ or ..\\ sequences targeting upload.php
• Implement file integrity monitoring on web-accessible directories to detect unauthorized file creation
• Deploy web application firewalls (WAF) with rules to block path traversal attempts
• Use endpoint detection tools to identify web shell execution patterns

Monitoring Recommendations

• Enable verbose logging on the web server to capture full request parameters
• Set up alerts for new executable file creation in web directories
• Monitor for command execution spawned from web server processes (e.g., www-data, apache)
• Review access logs regularly for suspicious POST requests to upload endpoints

How to Mitigate CVE-2019-25480

Immediate Actions Required

• Remove or disable the vulnerable upload.php script if not required for operations
• Implement strict access controls to restrict access to the upload functionality
• Deploy a web application firewall (WAF) to filter path traversal attempts
• Review and remove any unauthorized files that may have been uploaded to the web root

Patch Information

No official vendor patch information is currently available in the CVE data. Organizations should consult the VulnCheck Advisory for the latest remediation guidance. If the application is no longer maintained, consider migrating to an alternative solution.

Workarounds

• Restrict network access to the upload endpoint using firewall rules or .htaccess configurations
• Implement server-side input validation to reject path traversal sequences in file parameters
• Configure the upload directory outside the web root with strict permissions
• Disable PHP execution in upload directories using web server configuration directives

# Example: Disable PHP execution in upload directory (Apache)
# Add to .htaccess in the upload directory
<Directory /var/www/uploads>
    php_admin_flag engine off
    <FilesMatch "\.(php|phtml|php3|php4|php5|phps)$">
        Deny from all
    </FilesMatch>
</Directory>