CVE-2023-53944: 
NixOS vulnerability analysis and mitigation

CVE-2023-53944 is a path traversal vulnerability in EasyPHP Webserver version 14.1 that allows remote users with low privileges to read files outside the web document root by bypassing SecurityManager restrictions. Attackers exploit this by sending crafted GET requests containing URL-encoded directory traversal sequences (e.g., /..%5c..%5c) to access sensitive system files such as C:\windows\win.ini. The CVE was published on December 18, 2025, with the CNA being VulnCheck. It carries a CVSS v3.1 base score of 6.5 (Medium) and a CVSS v4.0 base score of 7.1 (High) (VulnCheck Advisory, NVD).

The vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory — Path Traversal). The root cause is insufficient sanitization of URL-encoded path separator characters (%5c, the encoded form of \) in HTTP GET requests, which allows attackers to bypass the application's SecurityManager path restrictions. By chaining multiple encoded traversal sequences, a low-privileged remote attacker can navigate above the web root and read arbitrary files on the underlying Windows filesystem. A public proof-of-concept exploit is available on Exploit-DB (EDB-51430) (Exploit-DB, VulnCheck Advisory).

Successful exploitation results in unauthorized read access to files outside the intended web root, with a high confidentiality impact and no integrity or availability impact. An attacker can retrieve sensitive system configuration files (e.g., win.ini, application configuration files, credential stores) that may facilitate further reconnaissance or targeted attacks against the host or connected systems. The vulnerability is limited to information disclosure and does not directly enable code execution or data modification (VulnCheck Advisory, NVD).

A public proof-of-concept exploit is available on Exploit-DB (EDB-51430) and referenced by VulnCheck, and CISA-ADP has also tagged the Exploit-DB reference as an exploit resource. There is currently no evidence of active in-the-wild exploitation. The EPSS score is approximately 0.22%, indicating a low but non-negligible probability of exploitation in the near term. No threat actor attribution or CISA KEV catalog listing has been identified for this CVE (Exploit-DB, VulnCheck Advisory, NVD).

1. Reconnaissance: Identify internet-facing or network-accessible EasyPHP Webserver 14.1 instances using tools like Shodan, Censys, or network scanning (e.g., nmap), looking for the default HTTP port.
2. Authenticate or obtain low-privileged access: The vulnerability requires low-privileged credentials; obtain or use any valid user account on the EasyPHP instance.
3. Craft the traversal request: Construct a GET request using URL-encoded backslash sequences to traverse directories above the web root. Example: GET /..%5c..%5c..%5cwindows%5cwin.ini HTTP/1.1
4. Send the request: Deliver the crafted request to the target server using a browser, curl, or a custom script. The SecurityManager fails to decode and block the encoded traversal sequences.
5. Read sensitive files: Review the server's response, which will contain the contents of the targeted file (e.g., win.ini). Repeat with different target paths to enumerate configuration files, credentials, or other sensitive data (Exploit-DB, VulnCheck Advisory).

• Network: HTTP GET requests to the EasyPHP Webserver containing URL-encoded backslash sequences (%5c) in the path, particularly patterns like /..%5c..%5c; requests targeting paths referencing system files (e.g., windows, win.ini, system32).
• Logs: EasyPHP access logs showing GET requests with %5c or %2f encoded traversal sequences returning HTTP 200 responses for paths outside the web root; repeated requests from a single IP to multiple system file paths.
• File System: No direct file system artifacts are expected from read-only exploitation, but audit logs may show unexpected file read events on sensitive system files if OS-level auditing is enabled.

EasyPHP Webserver 14.1 is end-of-life software with no available patch from the vendor. The recommended remediation steps are: (1) immediately isolate or take offline any exposed EasyPHP Webserver 14.1 instance; (2) migrate to a supported, actively maintained web server (e.g., Apache, Nginx, IIS); (3) if immediate migration is not possible, restrict network access using firewall rules or network segmentation; (4) deploy a Web Application Firewall (WAF) configured to detect and block directory traversal patterns including URL-encoded variants; and (5) conduct a security audit to determine whether sensitive files were accessed (VulnCheck Advisory, NVD).