CVE-2002-1345 in ncftp
Summary
by MITRE
Directory traversal vulnerabilities in multiple FTP clients on UNIX systems allow remote malicious FTP servers to create or overwrite files as the client user via filenames containing /absolute/path or .. (dot dot) sequences.
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Analysis
by VulDB Data Team • 01/21/2025
The vulnerability identified as CVE-2002-1345 represents a critical directory traversal flaw affecting multiple ftp clients operating on unix-based systems. This security weakness stems from insufficient input validation within ftp client implementations that fail to properly sanitize filenames received from remote ftp servers during file transfer operations. The vulnerability specifically manifests when ftp clients process filenames containing absolute path references or dot dot sequences that navigate up directory hierarchies. Attackers can exploit this weakness by configuring a malicious ftp server to send specially crafted filenames that contain sequences such as /absolute/path or .. components, which when processed by vulnerable ftp clients can result in unintended file system modifications.
The technical implementation of this vulnerability resides in the ftp client's handling of file path resolution during download operations. When an ftp client receives a filename containing directory traversal sequences, the client's path parsing logic fails to properly validate or sanitize these paths before attempting to create or overwrite files on the local system. This flaw directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability allows attackers to bypass normal file system access controls and potentially execute arbitrary file system operations with the privileges of the ftp client process, which typically runs with the permissions of the user who initiated the ftp session.
The operational impact of CVE-2002-1345 extends beyond simple file creation or overwriting operations, as it can enable attackers to manipulate the local file system in potentially harmful ways. An attacker could leverage this vulnerability to overwrite critical system files, create malicious files that execute when the user interacts with the system, or even establish persistent backdoors through carefully crafted file paths. The severity of this vulnerability is particularly concerning because ftp clients are commonly used for automated file transfers and system administration tasks, meaning that exploitation could occur without user intervention. This makes the vulnerability especially dangerous in environments where ftp clients are used to transfer sensitive data or where automated processes rely on ftp connectivity for system operations.
Mitigation strategies for CVE-2002-1345 should focus on both immediate client-side patches and broader operational security measures. System administrators should ensure that all ftp client software is updated to versions that properly sanitize filenames and validate path components before processing them. The implementation of network-level controls such as firewalls and intrusion detection systems can help prevent connections to known malicious ftp servers. Additionally, organizations should implement strict file transfer policies that limit the use of ftp clients for sensitive operations and consider migrating to more secure file transfer protocols such as sftp or ftps that provide better authentication and encryption mechanisms. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1078 Valid Accounts and T1566 Phishing, as attackers may use compromised accounts or social engineering to gain access to systems where vulnerable ftp clients are in use, and the exploitation can lead to privilege escalation and persistence within the compromised environment.