CVE-2004-2309 in Crob Ftp Server
Summary
by MITRE
Directory traversal vulnerability in Crob FTP Server 3.5.1 allows local users to browse outside the FTP root via multiple ../ (dot dot slash) in the DIR command.
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Analysis
by VulDB Data Team • 08/30/2025
The directory traversal vulnerability identified as CVE-2004-2309 affects Crob FTP Server version 3.5.1 and represents a critical security flaw that enables local attackers to escape the designated FTP root directory boundaries. This vulnerability specifically manifests through the DIR command implementation which fails to properly validate or sanitize directory path inputs containing multiple ../ sequences. The flaw allows malicious users to navigate upward through the file system hierarchy and access files or directories outside the intended FTP server root, potentially exposing sensitive system information or unauthorized data access.
This vulnerability maps directly to CWE-22, which defines improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The technical implementation flaw occurs when the FTP server processes directory listing requests without adequately filtering or normalizing path components that contain parent directory references. The use of multiple ../ sequences in the DIR command bypasses expected security controls and allows attackers to construct malicious path requests that traverse the file system structure beyond the intended boundaries. This type of vulnerability typically arises from insufficient input validation and inadequate path normalization routines within the server's file system access controls.
The operational impact of this vulnerability extends beyond simple unauthorized file access to potentially enable more sophisticated attacks including privilege escalation, data exfiltration, and system reconnaissance. Local users who can access the FTP server can leverage this flaw to explore the underlying file system, potentially discovering sensitive configuration files, user credentials, system binaries, or other confidential information. The vulnerability's exploitation requires minimal technical expertise and can be automated, making it particularly dangerous in environments where FTP services are exposed to untrusted users or where local access is not properly controlled. Attackers could use this vulnerability to identify system architecture details, locate weak configurations, or discover additional attack vectors within the compromised system.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and path normalization mechanisms within the FTP server implementation. System administrators should immediately upgrade to patched versions of Crob FTP Server or apply available security patches that address the directory traversal flaw. Additionally, implementing proper access controls and limiting local user privileges can reduce the attack surface for this vulnerability. Network segmentation and firewall rules should restrict unnecessary FTP access, while monitoring systems should be configured to detect unusual directory traversal patterns in FTP command logs. The vulnerability also highlights the importance of following secure coding practices as outlined in the OWASP Secure Coding Guidelines and aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through legitimate system access. Organizations should conduct comprehensive security assessments to identify similar path traversal vulnerabilities in other FTP implementations and ensure that all file system access controls properly validate and sanitize user inputs to prevent similar exploitation scenarios.