CVE-2023-53941: 
NixOS vulnerability analysis and mitigation

CVE-2023-53941 is an OS command injection vulnerability in EasyPHP Webserver version 14.1 that allows unauthenticated remote attackers to execute arbitrary system commands with administrative privileges. The vulnerability was assigned by VulnCheck and published on December 18, 2025, with NVD initial analysis completed on December 26, 2025. Only EasyPHP Webserver 14.1 is confirmed affected. It carries a CVSS v3.1 base score of 9.8 (Critical) and a CVSS v4.0 base score of 9.3 (Critical), both assigned by VulnCheck (VulnCheck Advisory, NVD).

The vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), rooted in insufficient sanitization of user-supplied input in the app_service_control parameter within the application's settings handler. An unauthenticated attacker can send a crafted HTTP POST request to /index.php?zone=settings with a malicious app_service_control value containing OS command delimiters or injection sequences, which the server then passes unsanitized to an underlying system call. No authentication, special privileges, or user interaction is required, making this trivially exploitable over the network. A public proof-of-concept exploit is available on Exploit-DB (Exploit-DB PoC, VulnCheck Advisory).

Successful exploitation grants an unauthenticated attacker the ability to execute arbitrary OS commands with administrative privileges on the underlying host running EasyPHP Webserver 14.1. This results in full compromise of confidentiality, integrity, and availability — attackers can read or exfiltrate sensitive data, modify or delete files, install malware or backdoors, and potentially use the compromised host as a pivot point for lateral movement within the network (VulnCheck Advisory, NVD).

A public proof-of-concept exploit is available on Exploit-DB (exploit #51430) and referenced by VulnCheck, lowering the bar for exploitation significantly. As of the time of disclosure, there is no confirmed evidence of active in-the-wild exploitation, and the vulnerability has not been added to the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.0765 (~7.6%), reflecting moderate probability of exploitation in the near term. No specific threat actor attribution has been reported (Exploit-DB PoC, VulnCheck Advisory).

1. Reconnaissance: Identify internet-facing or network-accessible instances of EasyPHP Webserver 14.1 using tools like Shodan or Censys, searching for the EasyPHP web interface (typically running on port 80 or 8080).
2. Confirm target: Access the EasyPHP web interface and verify the presence of the settings panel at /index.php?zone=settings to confirm the vulnerable version is running.
3. Craft malicious payload: Prepare a POST request targeting /index.php?zone=settings with the app_service_control parameter containing an OS command injection payload, e.g., app_service_control=start|whoami or using shell metacharacters such as ;, &&, or | to chain commands.
4. Send the request: Transmit the crafted POST request without any authentication headers. Example using curl:

curl -X POST 'http://<target>/index.php?zone=settings' --data 'app_service_control=start|<malicious_command>'

5. Achieve command execution: The server processes the injected command with administrative privileges, enabling the attacker to establish a reverse shell, create a backdoor user, or exfiltrate data (Exploit-DB PoC, VulnCheck Advisory).

• Network: Unexpected HTTP POST requests to /index.php?zone=settings containing shell metacharacters (|, ;, &&, ||) or encoded equivalents in the app_service_control parameter body; outbound connections from the EasyPHP server process to unknown external IPs (potential reverse shell activity).
• Logs: Web server access logs showing POST requests to /index.php?zone=settings with anomalous or encoded app_service_control values; error logs indicating unexpected process spawning or command execution failures.
• Process: Unusual child processes spawned by the EasyPHP web server process (e.g., cmd.exe, powershell.exe on Windows, or /bin/sh, /bin/bash on Linux); new scheduled tasks or services created by the web server account.
• File System: Presence of new executable files, web shells, or scripts in the EasyPHP installation directory or web root; modification timestamps on system files inconsistent with normal operations.

No vendor-issued patch has been publicly confirmed for EasyPHP Webserver 14.1 as of the disclosure date. Immediate recommended actions include: restricting network access to the EasyPHP web interface using firewall rules to allow only trusted IP addresses; deploying a Web Application Firewall (WAF) with rules to detect and block OS command injection patterns in POST body parameters; disabling the EasyPHP service if it is not critically required; and monitoring system and web server logs for suspicious activity. Organizations should conduct a security audit of affected systems and consider migrating to an actively maintained web server solution (VulnCheck Advisory, RedHat CVE).

The vulnerability received coverage from automated CVE tracking services and security aggregators including VulnDB, CVEFeed, and The Hacker Wire shortly after publication. CISA included it in a weekly vulnerability bulletin (SB25-356). Community discussion was limited, with social media mentions primarily from automated CVE notification accounts on Bluesky. No notable independent researcher commentary or vendor statements beyond VulnCheck's advisory have been identified (CISA Bulletin, VulnCheck Advisory).