CVE-2001-0963 in SpoonFTP
Summary
by MITRE
Directory traversal vulnerability in SpoonFTP 1.1 allows local and sometimes remote attackers to access files outside of the FTP root via a ... (modified dot dot) in the CD (CWD) command.
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Analysis
by VulDB Data Team • 05/24/2019
The vulnerability identified as CVE-2001-0963 represents a directory traversal flaw within SpoonFTP version 1.1 that fundamentally compromises the security boundaries of the file transfer protocol implementation. This issue arises from insufficient input validation in the CD (CWD) command processing, where the software fails to properly sanitize directory path references. The vulnerability specifically manifests when attackers exploit the ... (modified dot dot) sequence in directory change commands, allowing unauthorized access to files beyond the designated FTP root directory. The flaw enables both local and remote attackers to bypass intended access controls and potentially gain access to sensitive system files, configuration data, or other restricted resources that should remain protected within the FTP server's operational boundaries.
The technical implementation of this vulnerability stems from a classic path traversal weakness that falls under CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The flaw occurs because SpoonFTP 1.1 does not adequately validate or canonicalize directory paths submitted through the CWD command, allowing attackers to manipulate the current working directory to navigate upward through the file system hierarchy. When the FTP server processes commands containing sequences such as ../../../../../etc/passwd, it fails to properly resolve these paths against the intended root directory, thereby permitting access to files outside the designated FTP access scope. This vulnerability directly violates the principle of least privilege and represents a fundamental failure in access control implementation within the FTP server's directory handling mechanisms.
The operational impact of CVE-2001-0963 extends beyond simple unauthorized file access, as it provides attackers with potential pathways to escalate their privileges and compromise the overall system integrity. Local attackers can exploit this vulnerability to access sensitive configuration files, user credentials, or system binaries that may contain critical information for further exploitation. Remote attackers, when able to submit CWD commands to the FTP service, can potentially access system files such as password databases, configuration files, or other sensitive data that should remain isolated from unauthorized access. The vulnerability also enables attackers to perform reconnaissance activities by exploring system directories and identifying other potential targets or vulnerabilities within the broader system infrastructure. This type of vulnerability directly aligns with ATT&CK technique T1083, which covers directory and file searches, and can facilitate subsequent attack phases including privilege escalation and lateral movement within compromised environments.
Mitigation strategies for this directory traversal vulnerability should focus on implementing proper input validation and canonicalization of directory paths within the FTP server implementation. The most effective immediate solution involves patching the SpoonFTP software to version 1.2 or later, which includes proper path validation and normalization mechanisms that prevent the exploitation of path traversal sequences. Organizations should also implement network segmentation and access control measures to limit exposure of FTP services to untrusted networks and ensure that FTP servers operate with minimal necessary privileges. Additional defensive measures include implementing proper logging and monitoring of FTP commands, particularly CWD and CD commands, to detect anomalous path traversal attempts. The implementation of secure coding practices and regular security assessments of network services can prevent similar vulnerabilities from occurring in other FTP implementations or related network protocols. System administrators should also consider implementing intrusion detection systems that can identify and alert on suspicious FTP command sequences that attempt to exploit directory traversal vulnerabilities.