CVE-2001-0255 in FTP++ Server
Summary
by MITRE
FaSTream FTP++ Server 2.0 allows remote attackers to list arbitrary directories by using the "ls" command and including the drive letter name (e.g. C:) in the requested pathname.
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Analysis
by VulDB Data Team • 03/10/2025
The vulnerability identified as CVE-2001-0255 affects the FaSTream FTP++ Server version 2.0, representing a critical directory traversal flaw that enables remote attackers to access arbitrary file system locations. This vulnerability stems from insufficient input validation within the server's implementation of the "ls" command, which processes directory listing requests without properly sanitizing user-supplied pathnames that may contain drive letter specifications. The flaw operates by accepting user input that includes drive letter identifiers such as "C:" within directory paths, allowing unauthorized access to system directories that should remain protected from remote enumeration.
The technical implementation of this vulnerability aligns with CWE-22, known as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", where the server fails to properly validate and restrict file system access based on user-provided input. Attackers can exploit this weakness by sending specially crafted "ls" commands that include drive letters and directory paths, effectively bypassing normal access controls and potentially exposing sensitive system files, configuration data, and user information. The vulnerability exists at the application layer where the FTP server processes user requests without implementing proper path validation mechanisms.
Operationally, this vulnerability presents significant security implications for systems running the affected FaSTream FTP++ Server version. Remote attackers can leverage this flaw to perform unauthorized directory enumeration, potentially discovering sensitive files, system configurations, and user data stored on the server. The impact extends beyond simple information disclosure, as successful exploitation could lead to further attacks including privilege escalation, data exfiltration, and system compromise. The vulnerability affects the server's integrity and confidentiality by allowing unauthorized access to file system resources that should be restricted to authorized users only.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization for all user-supplied pathnames within the FTP server implementation. System administrators should immediately apply vendor patches or updates if available, or consider implementing network-level restrictions to limit access to the FTP service. The solution involves enforcing strict path validation that prevents the inclusion of drive letters or absolute paths in directory listing requests, ensuring that all user input is properly normalized and restricted to predefined safe directories. Additionally, implementing proper access controls and monitoring for suspicious directory listing activities can help detect and prevent exploitation attempts. Organizations should also consider implementing network segmentation and firewall rules to restrict access to FTP services to trusted networks only, following the principle of least privilege as outlined in cybersecurity best practices and the ATT&CK framework's defense evasion techniques.