CVE-2002-2433 in NetWare
Summary
by MITRE
NWFTPD.nlm before 5.03b in the FTP server in Novell NetWare allows remote authenticated users to cause a denial of service (abend) via a crafted ABOR command.
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Analysis
by VulDB Data Team • 05/04/2026
The vulnerability identified as CVE-2002-2433 affects the NWFTPD.nlm FTP server component in Novell NetWare operating systems prior to version 5.03b. This represents a denial of service weakness that specifically targets the FTP service implementation within the NetWare environment. The flaw manifests when the server processes a specially crafted ABOR command, which is typically used to abort an ongoing file transfer operation. The vulnerability operates at the protocol level and requires authentication to exploit, making it a targeted attack vector rather than a widespread remote exploit. From a cybersecurity perspective, this vulnerability demonstrates how even authenticated users can leverage legitimate protocol functions to disrupt service availability, highlighting the importance of proper input validation and error handling in network services.
The technical implementation of this vulnerability stems from inadequate input validation within the ABOR command handler of the NWFTPD.nlm module. When processing the crafted ABOR command, the FTP server fails to properly validate or sanitize the command parameters, leading to an abnormal program termination or system abend. This type of flaw falls under the category of improper input validation as classified by CWE-20, where the system does not adequately validate user-supplied data before processing it. The vulnerability specifically targets the command parsing logic that handles the ABOR command, which is part of the standard ftp protocol specification but is implemented in a way that does not properly handle malformed or unexpected command parameters. The lack of proper boundary checking and memory management in this command handler results in the server crashing and ceasing to provide FTP services to legitimate users.
The operational impact of CVE-2002-2433 extends beyond simple service disruption to potentially compromise the overall availability and reliability of network services within Novell NetWare environments. When exploited, this vulnerability can cause the FTP server to crash and restart, leading to temporary unavailability of file transfer services that may be critical for business operations. Organizations relying on NetWare for file sharing and network services could experience significant downtime, particularly in environments where FTP services are heavily utilized for data exchange and file management. The vulnerability affects systems where the FTP server is running in a production environment, potentially disrupting workflows and data access for multiple users simultaneously. From an attack perspective, this vulnerability represents a low-effort method for adversaries to cause service disruption, making it particularly concerning for environments where such attacks could be used as part of broader operational disruption campaigns.
The exploitation of this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. While the vulnerability requires authentication to exploit, it demonstrates how legitimate protocol functions can be weaponized to cause system instability. Organizations should implement proper access controls and monitor for unusual FTP command patterns that might indicate attempted exploitation. The vulnerability also highlights the importance of maintaining up-to-date system patches and monitoring for known vulnerabilities in legacy systems. Security practitioners should consider implementing network segmentation to limit the potential impact of such attacks and ensure that FTP services are properly monitored for abnormal behavior. The recommended mitigation strategy involves applying the vendor-supplied patch that addresses the input validation issue in the ABOR command handler, thereby preventing the malformed command from causing system crashes. Additionally, implementing proper logging and monitoring of FTP server activities can help detect potential exploitation attempts and provide early warning of such attacks.