CVE-2005-4888 in NetWare
Summary
by MITRE
NWFTPD.nlm before 5.06.04 in the FTP server in Novell NetWare allows remote attackers to cause a denial of service (excessive stale connections) by establishing many FTP sessions, which persist in the Not-Logged-In state after each session is completed.
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Analysis
by VulDB Data Team • 05/04/2026
The vulnerability described in CVE-2005-4888 represents a significant denial of service weakness within Novell NetWare's NWFTPD.nlm FTP server component. This flaw affects versions prior to 5.06.04 and demonstrates a classic resource exhaustion attack vector that can severely impact system availability. The vulnerability specifically targets the FTP server's handling of session management, creating a scenario where connections remain in a persistent not-logged-in state even after session termination, leading to cumulative resource consumption that can eventually render the system unusable.
The technical implementation of this vulnerability stems from inadequate connection state management within the FTP server daemon. When remote attackers establish multiple FTP sessions, each connection remains in a stale state within the server's connection table even after the session is properly terminated. This behavior violates proper connection lifecycle management principles and creates a memory leak scenario where the server continuously accumulates unused connection slots. The flaw operates at the network protocol level, specifically affecting the FTP protocol implementation within the NetWare operating system environment, and represents a failure in proper resource cleanup and connection state tracking mechanisms.
From an operational impact perspective, this vulnerability creates a severe availability risk for systems running affected NetWare FTP services. Attackers can systematically consume server resources by establishing numerous concurrent sessions that persist in memory, effectively creating a resource exhaustion condition that prevents legitimate users from establishing new connections. The attack is particularly insidious because it requires minimal resources to execute and can be sustained over extended periods, making it difficult to distinguish from legitimate high-traffic scenarios. This vulnerability directly maps to CWE-400, which categorizes improper resource management and resource exhaustion issues, and aligns with ATT&CK technique T1499.004 for network denial of service attacks.
The mitigation strategy for this vulnerability requires immediate patch application to upgrade NWFTPD.nlm to version 5.06.04 or later, which contains the necessary fixes for proper connection state cleanup. System administrators should also implement connection rate limiting and monitoring mechanisms to detect unusual session patterns that might indicate exploitation attempts. Network-level protections including firewall rules that limit concurrent FTP connections and connection timeouts can provide additional defense-in-depth measures. The vulnerability highlights the importance of proper connection lifecycle management and resource cleanup in server applications, emphasizing the need for robust session handling mechanisms that prevent accumulation of stale connections in server memory. Organizations should conduct thorough testing of patches in controlled environments before deployment to ensure compatibility with existing NetWare infrastructure and services.