CVE-2006-5949 in ALFTP FTP Server
Summary
by MITRE
Directory traversal vulnerability in ALTools ALFTP FTP Server 4.1 beta 1, and possibly earlier, allows remote attackers to create arbitrary directories via directory traversal sequences in a MKD request. NOTE: the provenance of this information is unknown; details are obtained from third party sources.
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Analysis
by VulDB Data Team • 04/27/2026
The directory traversal vulnerability identified in ALTools ALFTP FTP Server version 4.1 beta 1 represents a critical security flaw that enables remote attackers to manipulate the file system through crafted MKD (Make Directory) requests. This vulnerability falls under the CWE-22 category, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw allows adversaries to create arbitrary directories outside of the intended file system boundaries, potentially compromising the entire server infrastructure and enabling further malicious activities.
The technical implementation of this vulnerability occurs when the ALFTP server fails to properly validate or sanitize directory names submitted through the MKD command. Attackers can exploit this weakness by crafting directory traversal sequences such as "../" or "../../../" within their MKD requests, which bypass normal path validation mechanisms. When the server processes these malformed directory names, it interprets them as legitimate commands to create directories at arbitrary locations within the file system hierarchy. This allows unauthorized users to traverse beyond the designated FTP root directory and create directories in sensitive system locations, potentially leading to privilege escalation or system compromise.
The operational impact of this vulnerability extends beyond simple directory creation capabilities and represents a significant threat to server integrity and data security. Remote attackers can leverage this vulnerability to establish persistent access points within the system, potentially creating backdoors or hiding malicious files in system directories. The attack surface is particularly concerning because it operates at the protocol level, meaning that any user with access to the FTP server can exploit this weakness without requiring elevated privileges. The vulnerability also demonstrates a fundamental flaw in input validation and access control mechanisms, which may leave other aspects of the server exposed to similar attacks. According to ATT&CK framework, this vulnerability maps to T1078 (Valid Accounts) and T1566 (Phishing) as attackers can use the compromised system to establish persistent access or move laterally within networks.
Mitigation strategies for this vulnerability should focus on immediate patching of the ALFTP server software to the latest version that addresses the directory traversal flaw. System administrators should implement network-level controls such as firewall rules to restrict FTP access to trusted networks and limit the exposure of the vulnerable server. Additionally, implementing proper input validation and sanitization measures within the FTP server configuration can help prevent malicious directory traversal sequences from being processed. The use of secure FTP protocols such as FTPS or SFTP is recommended to provide encrypted communication channels that can help mitigate some attack vectors. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other network services, as this type of path traversal flaw is commonly found in various FTP implementations and can be exploited across multiple systems within an organization's infrastructure.