CVE-2010-2695 in Xlight FTP Server
Summary
by MITRE
Directory traversal vulnerability in the SFTP/SSH2 virtual server in Xlight FTP Server 3.5.0, 3.5.5, and possibly other versions before 3.6 allows remote authenticated users to read, overwrite, or delete arbitrary files via .. (dot dot) sequences in the (1) ls, (2) rm, (3) rename, and other unspecified commands.
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Analysis
by VulDB Data Team • 01/22/2025
The vulnerability identified as CVE-2010-2695 represents a critical directory traversal flaw within the SFTP/SSH2 virtual server component of Xlight FTP Server versions 3.5.0 and 3.5.5, with potential impacts extending to other versions prior to 3.6. This security weakness fundamentally compromises the file system access controls that are essential for maintaining data integrity and confidentiality in networked environments. The vulnerability specifically affects the secure file transfer protocol implementation, which is critical for enterprise security infrastructure where sensitive data is routinely transferred and stored.
The technical exploitation of this vulnerability occurs through the manipulation of directory traversal sequences using the .. (dot dot) notation within specific SFTP commands. Attackers with authenticated access can leverage this flaw to bypass normal file system restrictions and perform unauthorized operations including reading arbitrary files, overwriting existing files, or deleting critical system components. The vulnerability affects multiple commands including ls for directory listing, rm for file removal, and rename for file renaming operations, indicating a systemic flaw in how the application processes path traversal sequences rather than isolated command implementations. This type of vulnerability is categorized under CWE-22, which specifically addresses Improper Limitation of a Pathname to a Restricted Directory, making it a well-documented and severe class of security weakness.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it provides attackers with the capability to manipulate the underlying file system in ways that could lead to complete system compromise. An authenticated attacker could potentially escalate privileges, access sensitive configuration files, read system logs, or corrupt critical application data. The vulnerability's presence in the SFTP/SSH2 virtual server component is particularly concerning because these protocols are designed to provide secure communication channels, making the exploitation of such flaws especially dangerous in environments where data confidentiality and integrity are paramount. This weakness aligns with ATT&CK technique T1078 which covers Valid Accounts and T1566 which addresses Phishing, as the vulnerability requires legitimate authentication to exploit but could be leveraged for broader system compromise.
The exploitation of this vulnerability demonstrates a fundamental flaw in input validation and path resolution mechanisms within the Xlight FTP Server implementation. The application fails to properly sanitize or validate directory traversal sequences in its SFTP command processing, allowing maliciously crafted path references to navigate outside of intended directories. This represents a classic case of insufficient input sanitization where the system assumes that all user-provided paths are legitimate and properly formatted. Organizations relying on this software for secure file transfers face significant risk of data breaches, system corruption, or unauthorized access to sensitive information. The vulnerability's potential for exploitation across multiple commands indicates that the root cause lies in the core file system access layer rather than individual command implementations, making the remediation more complex and requiring comprehensive application-level fixes. The security implications are particularly severe given that SFTP/SSH2 are protocols specifically designed for secure file operations, and this flaw undermines the fundamental security assumptions of these protocols.