CVE-2024-23692 identifies a critical security vulnerability in Rejetto HTTP File Server (HFS) versions up to 2.3m, specifically a template injection flaw categorized under CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine). The vulnerability allows a remote attacker to inject malicious template code via crafted HTTP requests, which the server processes without adequate sanitization. This leads to arbitrary command execution on the host system without requiring any authentication or user interaction. The root cause is the failure of the template engine in HFS to properly neutralize special characters or elements that control template logic, enabling attackers to manipulate server-side execution flow. Since Rejetto HFS 2.3m is no longer supported, no official patches or fixes are available, increasing the risk for users who continue to deploy this software. The CVSS v3.1 base score of 9.8 reflects the vulnerability's critical nature, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability impacts confidentiality, integrity, and availability, as attackers can fully compromise the affected system, potentially gaining control over sensitive data and disrupting services. No known exploits are publicly reported yet, but the ease of exploitation and high impact make it a significant threat. Organizations using HFS for file sharing or lightweight web hosting must consider this vulnerability a severe risk.

For European organizations, the impact of CVE-2024-23692 is substantial. Many small to medium enterprises (SMEs) and niche service providers use Rejetto HFS due to its simplicity and lightweight nature. Successful exploitation can lead to full system compromise, allowing attackers to steal sensitive data, deploy ransomware, or use the compromised server as a foothold for lateral movement within networks. The lack of vendor support means no patches are forthcoming, increasing exposure duration. Critical infrastructure or organizations handling personal data under GDPR may face regulatory penalties if breaches occur. Additionally, compromised servers could be leveraged in broader cyber campaigns targeting European entities. The vulnerability's remote, unauthenticated nature makes it attractive for opportunistic attackers and automated scanning tools, increasing the likelihood of exploitation. Disruption of file sharing services can also impact business continuity, especially in sectors relying on HFS for internal or external file distribution.

Given the absence of official patches, European organizations should immediately cease using Rejetto HFS 2.3m or earlier versions. Migration to actively maintained and secure file server solutions is strongly advised. In the interim, organizations should implement strict network-level controls such as firewall rules to restrict access to HFS servers only to trusted IP addresses. Deploy web application firewalls (WAFs) with custom rules to detect and block suspicious template injection patterns in HTTP requests. Conduct thorough network scans to identify any instances of HFS in use. Monitor logs for unusual HTTP request patterns indicative of exploitation attempts. Employ intrusion detection/prevention systems (IDS/IPS) tuned for template injection signatures. Educate IT staff about the risks and signs of compromise related to this vulnerability. Finally, develop and test incident response plans to quickly contain and remediate any detected exploitation.