CVE-2001-0283 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in SunFTP build 9 allows remote attackers to read arbitrary files via .. (dot dot) characters in various commands, including (1) GET, (2) MKDIR, (3) RMDIR, (4) RENAME, or (5) PUT.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/07/2025
The vulnerability identified as CVE-2001-0283 represents a critical directory traversal flaw in SunFTP build 9 that exposes systems to remote exploitation through improper input validation. This weakness allows attackers to manipulate file system operations by injecting .. (dot dot) sequences into various FTP commands, fundamentally undermining the security boundaries of the file transfer protocol implementation. The vulnerability operates at the core of how the FTP server processes user-supplied paths, creating a pathway for unauthorized access to system resources beyond the intended directory structures.
The technical implementation of this vulnerability stems from inadequate sanitization of user inputs within the FTP server's command processing logic. When attackers submit commands containing directory traversal sequences such as .. in operations like GET, MKDIR, RMDIR, RENAME, or PUT, the server fails to properly validate or normalize the path components before executing file system operations. This failure creates a condition where the server interprets the traversal sequences as legitimate path navigation rather than malicious input, allowing access to files and directories outside the designated FTP root. The flaw specifically affects the path resolution mechanism that should enforce directory boundaries and prevent access to parent directories.
From an operational perspective, this vulnerability presents a severe risk to organizations relying on SunFTP for file transfer operations, as it enables attackers to read arbitrary files from the system. The impact extends beyond simple information disclosure to potentially allow full system compromise through access to configuration files, system binaries, and sensitive data repositories. Attackers could leverage this vulnerability to extract system credentials, access confidential documents, or gather intelligence about the underlying system architecture. The remote nature of the attack means that exploitation can occur from any network location without requiring local system access or authentication, making it particularly dangerous for publicly accessible FTP servers.
The vulnerability aligns with CWE-22, which classifies directory traversal attacks as a common weakness in input validation where attackers manipulate file system paths to access unauthorized resources. From an adversarial perspective, this flaw maps directly to ATT&CK technique T1071.004 for application layer protocol usage and T1566 for phishing with a malicious file, as attackers could use this vulnerability to retrieve system files that might contain credentials or other sensitive information. Organizations should implement immediate mitigations including patching the SunFTP server to the latest build, implementing strict input validation at the network level, and configuring firewall rules to restrict FTP access to trusted networks. Additionally, administrators should consider implementing network segmentation and monitoring for suspicious file access patterns that might indicate exploitation attempts. The vulnerability underscores the critical importance of proper input validation and path normalization in network services, particularly those handling file system operations, as it demonstrates how a single validation flaw can completely compromise system security boundaries.