CVE-2004-0677 in NETFile FTP
Summary
by MITRE
Fastream NETFile FTP Server 6.7.2.1085 and earlier allows remote attackers to cause a denial of service (temporary hang) via the cd command with an unusual argument, possibly due to multiple leading slashes and/or an access to the floppy drive ("A").
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Analysis
by VulDB Data Team • 07/08/2017
The vulnerability described in CVE-2004-0677 represents a denial of service weakness in Fastream NETFile FTP Server versions 6.7.2.1085 and earlier. This flaw manifests when remote attackers send a specially crafted cd command with an unusual argument structure that includes multiple leading slashes and attempts to access the floppy drive designated as "A". The attack vector exploits the server's inadequate input validation and processing mechanisms for directory change operations, specifically targeting the path resolution logic that handles unusual path formats.
The technical implementation of this vulnerability stems from the server's failure to properly sanitize and validate user input during the cd command execution. When the FTP server receives a command containing multiple leading slashes followed by a reference to the floppy drive, the internal path parsing routine becomes confused and enters a temporary hang state. This occurs because the server's path resolution algorithm does not adequately handle edge cases in path specification, particularly when dealing with redundant slash characters and device references. The flaw specifically affects the server's ability to process paths that contain excessive leading slashes or references to non-standard drive letters, causing the system to stall while attempting to resolve these malformed paths.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on Fastream NETFile FTP Server for file transfer operations. The temporary hang condition effectively renders the FTP service unavailable to legitimate users while the server remains unresponsive, creating a denial of service scenario that can persist until the system is manually restarted or the hanging process is terminated. The impact extends beyond simple service disruption as it can be exploited by malicious actors to create sustained availability issues, potentially affecting business operations and user productivity. Network administrators may find that the service becomes unresponsive to all commands while the problematic path resolution is being processed, making it difficult to diagnose and resolve the issue without direct server access.
The vulnerability aligns with CWE-121, which addresses buffer overflow conditions in command line arguments, and CWE-20, which covers improper input validation. From an ATT&CK framework perspective, this weakness maps to T1499.004, which covers network denial of service attacks, and T1566.001, which involves social engineering through spearphishing with a link. The attack requires minimal technical expertise to execute, making it particularly dangerous as it can be leveraged by attackers with limited knowledge of system internals. Organizations should implement immediate mitigations including updating to a patched version of Fastream NETFile FTP Server, implementing network-level restrictions to limit access to the FTP service, and configuring proper input validation rules at the network perimeter to prevent malformed cd commands from reaching the vulnerable server. Additionally, monitoring systems should be deployed to detect unusual patterns in FTP command sequences that might indicate exploitation attempts, and regular security assessments should be conducted to identify similar vulnerabilities in other network services.