CVE-2001-0646 in Rumpus FTP Server
Summary
by MITRE
Maxum Rumpus FTP Server 1.3.3 and 2.0.3 dev 3 allows a remote attacker to perform a denial of service (hang) by creating a directory name of a specific length.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2001-0646 affects the Maxum Rumpus FTP Server versions 1.3.3 and 2.0.3 development build 3, representing a classic denial of service weakness that can be exploited remotely. This flaw demonstrates how seemingly minor implementation issues in network services can lead to significant operational disruptions, particularly in environments where continuous availability is critical. The vulnerability specifically targets the server's handling of directory names, exposing a design flaw in the input validation and processing mechanisms that govern how the FTP server manages file system operations. The attack vector is straightforward yet effective, requiring only a remote connection to the vulnerable server to trigger the malicious condition that causes the service to hang or become unresponsive.
The technical implementation of this vulnerability stems from inadequate bounds checking within the directory creation functionality of the Rumpus FTP server. When an attacker crafts a directory name of a specific, predetermined length, the server's internal processing routines encounter a condition that causes them to enter an infinite loop or consume excessive system resources. This behavior aligns with CWE-129, which addresses issues related to insufficient validation of length parameters in input processing. The server's failure to properly validate or sanitize directory name lengths means that malicious input can cause the application to behave unpredictably, ultimately leading to a denial of service condition where legitimate users cannot access the FTP service. The specific length requirement suggests that the vulnerability exists in the buffer management or string processing code, where certain boundary conditions trigger unexpected behavior in the server's memory handling routines.
The operational impact of this vulnerability extends beyond simple service interruption, as it can severely compromise the availability and reliability of the FTP service for legitimate users. Organizations relying on the Rumpus FTP server for file transfers, data storage, or remote access capabilities would experience complete service disruption when exploited, potentially affecting business operations and user productivity. The remote nature of the attack means that adversaries can exploit this weakness from anywhere on the network without requiring physical access or authentication credentials, making it particularly dangerous in environments where FTP servers are exposed to untrusted networks. This vulnerability also demonstrates the importance of proper input validation in network services, as the attack does not require complex exploitation techniques but rather leverages the server's failure to handle edge cases in its input processing. The hanging behavior can persist until the server is manually restarted, creating a window of service unavailability that may be exploited for extended periods.
Mitigation strategies for CVE-2001-0646 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves upgrading to a patched version of the Maxum Rumpus FTP server that properly validates directory name lengths and implements robust input sanitization. System administrators should also consider implementing network-level restrictions such as firewall rules that limit access to the FTP service or monitor for unusual directory creation patterns that might indicate exploitation attempts. From a security engineering perspective, this vulnerability highlights the need for comprehensive testing of boundary conditions and input validation routines, particularly in protocols that handle user-supplied data. The ATT&CK framework categorizes this type of vulnerability under T1499, which covers network denial of service attacks, emphasizing that such weaknesses can be leveraged by adversaries to disrupt services and potentially create opportunities for additional attacks. Organizations should also implement monitoring solutions that can detect unusual server behavior or resource consumption patterns that might indicate exploitation of similar input validation vulnerabilities in other network services.