CVE-2004-1783 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in Net2Soft Flash FTP Server 1.0 allows remote attackers to read and create arbitrary files via a /.. (slash dot dot).
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Analysis
by VulDB Data Team • 09/04/2025
The directory traversal vulnerability identified in CVE-2004-1783 affects the Net2Soft Flash FTP Server version 1.0, representing a critical security flaw that enables remote attackers to manipulate file system access through improper input validation. This vulnerability specifically manifests when the server fails to adequately sanitize directory path inputs, allowing malicious actors to exploit the lack of proper path validation mechanisms. The flaw permits attackers to navigate beyond the intended directory boundaries by utilizing the /.. (slash dot dot) sequence, which is a well-known technique for bypassing directory restrictions in file systems. The vulnerability stems from the server's inability to properly interpret and validate relative path references, creating an opportunity for unauthorized file access and manipulation.
The technical implementation of this vulnerability operates through the exploitation of insufficient input validation within the FTP server's path handling mechanisms. When a client sends a request containing a directory traversal sequence such as /.., the server processes this input without proper sanitization, allowing the attacker to specify arbitrary file paths that should normally be restricted. This flaw directly relates to CWE-22, which categorizes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The vulnerability exists at the protocol level where the FTP server does not properly validate or canonicalize directory paths before processing file operations, creating a pathway for attackers to access files outside of the designated server directories. The implementation allows for both file reading and creation operations, amplifying the potential impact of the vulnerability.
Operationally, this vulnerability presents a severe threat to systems running the affected Net2Soft Flash FTP Server, as it enables attackers to access sensitive files, potentially including configuration data, user credentials, system logs, and other confidential information stored on the server. The ability to create arbitrary files through directory traversal allows for more sophisticated attacks such as planting malicious code, establishing backdoors, or modifying system files to maintain persistent access. Attackers can leverage this vulnerability to escalate privileges, gain unauthorized access to restricted areas of the file system, and potentially compromise the entire server. The remote nature of the attack means that exploitation can occur from any location without requiring physical access to the system, making the vulnerability particularly dangerous for networked environments. This type of vulnerability also aligns with ATT&CK technique T1078.004, which covers valid accounts and T1566.001 for credential harvesting, as attackers can use the traversal capability to access authentication-related files or create malicious accounts.
The impact of this vulnerability extends beyond immediate file access, as it can serve as a foothold for more extensive compromise within the network infrastructure. System administrators may not immediately detect unauthorized file access or creation activities, particularly if the traversal occurs through legitimate FTP operations. The vulnerability also demonstrates poor security practices in software development, specifically the lack of input validation and proper access control mechanisms. Organizations should implement immediate mitigations including applying vendor patches if available, configuring firewall rules to restrict FTP access, and implementing proper file system permissions to limit the impact of potential exploitation. Additionally, monitoring FTP server logs for suspicious path traversal attempts can help detect exploitation attempts. The vulnerability highlights the importance of proper input validation and the principle of least privilege in system design, as well as the necessity for regular security assessments and vulnerability scanning to identify similar flaws in other network services.