CVE-2024-0731 is a medium-severity vulnerability identified in PCMan FTP Server version 2.0.7. The flaw resides in the PUT Command Handler component of the FTP server software. Specifically, the vulnerability is classified under CWE-404, which relates to improper resource shutdown or release. An attacker can remotely exploit this vulnerability without requiring authentication or user interaction by sending a specially crafted PUT command to the server. Successful exploitation leads to a denial of service (DoS) condition, causing the FTP server to crash or become unresponsive, thereby disrupting legitimate file transfer operations. The CVSS 3.1 base score is 5.3, reflecting a network attack vector with low complexity and no privileges or user interaction needed, but with impact limited to availability only, without affecting confidentiality or integrity. Although no public exploits are currently known to be actively used in the wild, the vulnerability details have been publicly disclosed, increasing the risk of exploitation attempts. No official patches or updates have been linked yet, so affected organizations must consider interim mitigation strategies. The vulnerability affects only version 2.0.7 of PCMan FTP Server, which is a lightweight FTP server software commonly used in small to medium environments for file transfer services.

For European organizations, the primary impact of this vulnerability is service disruption due to denial of service attacks against FTP servers running PCMan FTP Server 2.0.7. This can interrupt business operations that rely on FTP for file exchange, such as data sharing between departments, partners, or external clients. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can lead to operational delays, potential loss of productivity, and reputational damage if critical services are affected. Organizations in sectors with high reliance on FTP for legacy or specialized workflows—such as manufacturing, logistics, and small-scale IT service providers—may be particularly vulnerable. Additionally, denial of service conditions could be leveraged as part of multi-stage attacks or to distract security teams during other malicious activities. Given the lack of authentication requirements, attackers can exploit this remotely from anywhere, increasing the threat surface. The absence of a patch means organizations must rely on network-level controls and monitoring to mitigate risk until an official fix is released.

1. Immediate mitigation should focus on restricting external access to PCMan FTP Server instances, ideally limiting connections to trusted IP addresses or internal networks using firewalls or access control lists (ACLs). 2. Deploy network intrusion detection or prevention systems (IDS/IPS) with signatures or heuristics to detect anomalous or malformed PUT commands targeting the FTP server. 3. Monitor FTP server logs closely for unusual PUT command activity or repeated connection attempts that could indicate exploitation attempts. 4. Consider temporarily disabling the PUT command functionality if the server configuration allows, or replacing PCMan FTP Server with a more secure and actively maintained FTP server software. 5. Implement rate limiting on FTP connections to reduce the risk of DoS attacks. 6. Maintain up-to-date backups and ensure incident response plans include procedures for FTP service outages. 7. Stay alert for official patches or updates from PCMan and apply them promptly once available. 8. Educate IT staff about this vulnerability and encourage proactive monitoring and rapid response to any signs of exploitation.