CVE-2000-0717 in FTP Server
Summary
by MITRE
GoodTech FTP server allows remote attackers to cause a denial of service via a large number of RNTO commands.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2000-0717 affects the GoodTech FTP server implementation and represents a classic denial of service attack vector through command flooding. This flaw manifests when remote attackers submit an excessive number of RNTO commands to the FTP server, causing system resources to become exhausted and ultimately leading to service unavailability. The RNTO command in FTP protocol is used to rename files, and the vulnerability exploits the server's insufficient input validation and resource management when processing these commands in rapid succession. This type of attack falls under the category of resource exhaustion attacks that target protocol implementation weaknesses rather than cryptographic vulnerabilities.
The technical exploitation of this vulnerability demonstrates a fundamental flaw in the server's command processing logic where it fails to implement proper rate limiting or command queue management. When multiple RNTO commands are received in quick succession, the GoodTech FTP server does not adequately validate or throttle the incoming requests, allowing malicious actors to consume system resources such as memory, CPU cycles, and connection handles. This behavior creates a scenario where legitimate users cannot access the FTP service due to the server being overwhelmed by the flood of commands. The vulnerability specifically aligns with CWE-400, which addresses resource exhaustion conditions in software implementations, and represents a failure in proper input sanitization and flow control mechanisms.
From an operational impact perspective, this vulnerability creates significant business disruption for organizations relying on GoodTech FTP services. The denial of service condition renders the FTP server completely inaccessible to legitimate users, potentially affecting critical data transfer operations and business continuity. Attackers can easily exploit this weakness using automated tools to send thousands of RNTO commands per second, making it a low-effort, high-impact attack vector. The vulnerability also presents challenges for network monitoring and incident response teams as the attack pattern can be difficult to distinguish from legitimate high-volume file renaming operations. Organizations may experience extended downtime while implementing patches or temporary workarounds, leading to productivity losses and potential customer dissatisfaction.
Mitigation strategies for CVE-2000-0717 should focus on implementing proper rate limiting and connection management within the FTP server configuration. Network administrators should consider deploying firewall rules or intrusion prevention systems to monitor and limit the rate of RNTO commands from individual IP addresses. The most effective long-term solution involves applying vendor-provided patches or upgrading to newer FTP server implementations that properly handle command flooding scenarios. Organizations should also implement logging and monitoring mechanisms to detect unusual command patterns that could indicate an ongoing attack. This vulnerability demonstrates the importance of implementing the principle of least privilege and proper input validation as outlined in the ATT&CK framework's defense in depth strategies. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar implementation weaknesses in other network services that may be susceptible to similar resource exhaustion attacks.