CVE-2004-1281 in FTP Client
Summary
by MITRE
The ftp_retr function in junkie 0.3.1 allows remote malicious FTP servers to overwrite arbitrary files via .. (dot dot) sequences in a filename.
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Analysis
by VulDB Data Team • 07/21/2017
The vulnerability identified as CVE-2004-1281 affects the ftp_retr function within junkie version 0.3.1, representing a critical directory traversal flaw that enables remote attackers to manipulate file operations on affected systems. This issue stems from inadequate input validation within the FTP client implementation, specifically when processing filenames that contain directory traversal sequences. The vulnerability manifests when a malicious FTP server responds to a file retrieval request with a filename containing .. (dot dot) sequences, which are commonly used to navigate up directory levels in file systems. When the ftp_retr function processes such filenames without proper sanitization, it fails to prevent path traversal attacks that could lead to arbitrary file overwrites on the client system. This flaw directly violates security principles by allowing unauthorized file system modifications through seemingly legitimate network operations.
The technical implementation of this vulnerability resides in the insufficient validation of filename parameters within the ftp_retr function, which operates under the assumption that remote FTP servers will provide legitimate filenames. The function fails to canonicalize or sanitize input paths before performing file operations, creating a path traversal condition that can be exploited by malicious FTP servers. According to CWE-22, this vulnerability maps to "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", a well-documented weakness that has plagued numerous applications across different platforms and protocols. The flaw essentially allows an attacker to bypass normal file system access controls and potentially overwrite files in directories that should be protected from modification by the client application. The vulnerability operates at the application layer and can be classified under the MITRE ATT&CK technique T1059.007 for command and scripting interpreter, specifically when the traversal leads to execution of malicious payloads through file overwrites.
The operational impact of CVE-2004-1281 extends beyond simple file overwrites to potentially enable more severe compromise scenarios. An attacker controlling a malicious FTP server can leverage this vulnerability to overwrite critical system files, configuration files, or even executable components that could lead to privilege escalation or system compromise. The vulnerability affects any system running junkie 0.3.1 that connects to untrusted FTP servers, making it particularly dangerous in environments where users might unknowingly connect to compromised FTP services. The attack vector is straightforward yet effective, requiring only that a victim connects to a malicious FTP server and attempts to retrieve a file with a specially crafted name. This type of vulnerability demonstrates the importance of input validation and secure coding practices in network protocol implementations, as the flaw exists in how the application processes network responses rather than in the network protocol itself. Organizations using affected versions of junkie should consider this vulnerability as a potential entry point for more sophisticated attacks, particularly in environments where FTP connectivity is common and where users may not be security-aware.
Mitigation strategies for CVE-2004-1281 should focus on both immediate patching and defensive measures. The primary recommendation involves upgrading to a newer version of junkie that contains proper input validation and sanitization for filename parameters in FTP operations. Until such an upgrade is possible, administrators should implement network-level controls to restrict FTP access to trusted servers only, thereby limiting exposure to malicious FTP servers. Additionally, implementing strict file access controls on systems running affected versions can help minimize the potential impact of successful exploitation. The vulnerability highlights the importance of the principle of least privilege in application design, where applications should never trust external inputs and should always validate and sanitize all data before processing. Network segmentation and monitoring for unusual FTP activity patterns can also serve as defensive measures against exploitation attempts. Security teams should also consider implementing automated vulnerability scanning tools that can detect the presence of this specific version of junkie and alert administrators to the potential risk of exploitation.