CVE-2023-53941
📋 TL;DR
EasyPHP Webserver 14.1 contains an unauthenticated OS command injection vulnerability that allows remote attackers to execute arbitrary system commands with administrative privileges. Attackers can exploit this by sending crafted POST requests to the vulnerable endpoint. All systems running the affected version are at risk.
💻 Affected Systems
- EasyPHP Webserver
📦 What is this software?
Webserver by Easyphp
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with administrative privileges, allowing attackers to install malware, steal data, pivot to other systems, or establish persistent backdoors.
Likely Case
Remote code execution leading to web server compromise, data exfiltration, or deployment of ransomware/cryptominers.
If Mitigated
Limited impact if proper network segmentation, least privilege, and monitoring are in place, though the vulnerability still allows initial access.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB and other sources, making this trivial to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://www.easyphp.org/
Restart Required: No
Instructions:
No official patch is available. Consider upgrading to a different web server solution or implementing workarounds.
🔧 Temporary Workarounds
Block Vulnerable Endpoint
allUse web server configuration or firewall rules to block access to /index.php?zone=settings
# Apache: RewriteRule ^/index\.php\?zone=settings - [F,L]
# Nginx: location ~* /index\.php\?zone=settings { deny all; }
Input Validation Filter
allImplement input validation to reject malicious app_service_control parameter values
# PHP example: if (preg_match('/[;&|`$]/', $_POST['app_service_control'])) { die('Invalid input'); }
🧯 If You Can't Patch
- Immediately remove EasyPHP Webserver 14.1 from internet-facing systems
- Implement strict network segmentation and monitor for suspicious POST requests to /index.php?zone=settings
🔍 How to Verify
Check if Vulnerable:
Check if EasyPHP Webserver version is 14.1 by examining installation directory or running the version check command.Check Version:
# Windows: type "C:\Program Files\EasyPHP\version.txt"
# Linux: cat /opt/easyphp/version.txtVerify Fix Applied:
Test if the vulnerable endpoint is accessible and if command injection is possible using safe test payloads (e.g., whoami).📡 Detection & Monitoring
Log Indicators:
- POST requests to /index.php?zone=settings with unusual app_service_control parameter values containing shell metacharacters (;, &, |, `, $)
Network Indicators:
- Unusual outbound connections from the web server to external IPs, especially on non-standard ports
SIEM Query:
source="web_server_logs" AND uri="/index.php" AND query_string="zone=settings" AND (param="app_service_control" AND value MATCHES "[;&|`$]")