CVE-1999-0201 in FTP Server
Summary
by MITRE
a quote cwd command on ftp servers can reveal the full path of the home directory of the "ftp" user.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability described in CVE-1999-0201 represents a classic information disclosure flaw affecting ftp server implementations. This issue specifically manifests when the quote cwd command is executed against ftp servers, allowing unauthorized users to discover the complete file system path of the home directory belonging to the ftp user account. The vulnerability stems from improper handling of the cwd command response, where the server inadvertently reveals directory structure information that should remain hidden from remote clients.
This technical flaw falls under the category of information disclosure vulnerabilities and aligns with CWE-200, which addresses the exposure of sensitive information to an unauthorized actor. The vulnerability exists because ftp servers do not properly sanitize their responses to the cwd command, particularly when the command is executed in a context that should restrict path exposure. The issue affects the security principle of least privilege by providing attackers with potentially valuable reconnaissance information about the server's file system organization. The exposure of the full path structure can enable attackers to plan more sophisticated attacks by understanding the server's directory hierarchy and potentially identifying weak points in the overall system architecture.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with crucial reconnaissance data that can be leveraged in subsequent exploitation phases. When an attacker can determine the exact location of the ftp user's home directory, they gain insights into the system's file organization that may reveal other sensitive directories or files. This information disclosure can be particularly damaging in environments where ftp services are used for legitimate file transfers but also serve as entry points for broader system compromise. The vulnerability is particularly concerning because it affects the fundamental security assumptions of ftp protocols and can be exploited by any user who can establish an ftp connection to the target server.
Mitigation strategies for CVE-1999-0201 should focus on implementing proper response sanitization for ftp commands, particularly those related to directory navigation. System administrators should ensure that ftp server implementations properly handle the cwd command without exposing full path information in their responses. The solution involves modifying server configurations to prevent the revelation of absolute paths during directory listing operations and implementing access controls that restrict path exposure to authorized users only. Organizations should also consider implementing network segmentation and firewall rules to limit access to ftp services, while adopting more secure file transfer protocols such as sftp or ftps that provide better security controls and prevent information disclosure through command responses. Additionally, regular security assessments should verify that ftp server implementations properly handle directory navigation commands without exposing sensitive path information to unauthorized users. The vulnerability demonstrates the importance of proper input validation and response handling in network services, as outlined in the ATT&CK framework's emphasis on information gathering techniques that can be exploited to gain system intelligence.