CVE-2023-53944 is a path traversal vulnerability identified in EasyPHP Webserver version 14.1. The flaw arises from improper limitation of pathnames to a restricted directory, allowing remote attackers to bypass the SecurityManager's directory access controls. Specifically, the vulnerability permits attackers to craft GET requests with encoded directory traversal payloads such as /..%5c..%5c, which the server fails to properly sanitize or normalize. This enables unauthorized access to files outside the intended document root directory, including sensitive system files like /windows/win.ini. The vulnerability requires no authentication or user interaction and can be exploited over the network (AV:N), with low attack complexity (AC:L). The CVSS 4.0 vector indicates no privileges are needed (PR:L), no user interaction (UI:N), and high confidentiality impact (VC:H), but no impact on integrity or availability. Although no public exploits are currently known, the vulnerability poses a significant risk of information disclosure, which could facilitate further attacks such as privilege escalation or lateral movement. The root cause is insufficient input validation and failure to canonicalize paths before access control checks. The vulnerability affects only version 14.1 of EasyPHP Webserver, and no patches or fixes are currently linked in the provided data, emphasizing the need for immediate mitigation steps by users.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive system and configuration files, potentially exposing credentials, internal configurations, or other critical information. Such data leakage can facilitate subsequent attacks including privilege escalation, lateral movement within networks, or targeted exploitation of disclosed information. Organizations running EasyPHP Webserver 14.1 in development, testing, or production environments are at risk, especially if the server is exposed to untrusted networks or the internet. The impact is heightened in sectors with stringent data protection requirements such as finance, healthcare, and government, where leakage of sensitive information could result in regulatory penalties and reputational damage. Additionally, the ease of exploitation without authentication increases the threat surface, making automated scanning and exploitation plausible. The vulnerability could also undermine trust in web applications hosted on affected servers, impacting business continuity and operational security.

European organizations should immediately audit their environments to identify any instances of EasyPHP Webserver version 14.1. If possible, upgrade to a patched version once available or consider migrating to alternative webserver solutions with active support. In the absence of an official patch, implement strict network-level access controls to restrict access to the EasyPHP Webserver from untrusted sources, ideally limiting it to internal networks or VPNs. Deploy web application firewalls (WAFs) configured to detect and block requests containing encoded directory traversal sequences such as /..%5c..%5c. Enhance input validation mechanisms to normalize and sanitize all incoming URL paths before processing. Monitor server logs for suspicious GET requests that include encoded traversal patterns and investigate any anomalies promptly. Additionally, consider employing file system permissions to restrict the webserver process’s access strictly to the document root and necessary directories, minimizing the impact of any traversal attempts. Regularly review and update security policies and incident response plans to address potential exploitation scenarios related to this vulnerability.