CVE-2008-2821 in Secure FTP
Summary
by MITRE
Directory traversal vulnerability in the FTP client in Glub Tech Secure FTP before 2.5.16 on Windows allows remote FTP servers to create or overwrite arbitrary files via a ..\ (dot dot backslash) in a response to a LIST command, a related issue to CVE-2002-1345.
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Analysis
by VulDB Data Team • 01/28/2025
The vulnerability identified as CVE-2008-2821 represents a critical directory traversal flaw in the FTP client component of Glub Tech Secure FTP versions prior to 2.5.16 on Windows systems. This security weakness stems from inadequate input validation within the client's handling of FTP LIST command responses, creating a pathway for remote attackers to manipulate file system operations through specially crafted responses from malicious FTP servers. The vulnerability specifically exploits the client's failure to properly sanitize directory path references that contain the ..\ sequence, which is a well-known pattern used in directory traversal attacks to navigate outside the intended directory structure.
The technical implementation of this vulnerability occurs when the FTP client processes directory listings returned by remote servers. During normal operation, when an FTP client executes a LIST command to retrieve directory contents, it expects standard directory entry formats. However, malicious FTP servers can respond with directory entries containing ..\ sequences that, when processed by the vulnerable client, cause the client to interpret these paths as commands to create or overwrite files in arbitrary locations on the local system. This behavior directly aligns with CWE-22, which categorizes directory traversal vulnerabilities as weaknesses that allow attackers to access files or directories outside of the intended scope through manipulation of input parameters.
The operational impact of this vulnerability extends beyond simple file system manipulation to encompass potential system compromise and data integrity violations. Attackers can leverage this weakness to overwrite critical system files, inject malicious code into the local file system, or create backdoor files that maintain persistent access to the compromised system. The vulnerability's relationship to CVE-2002-1345 demonstrates a pattern of similar directory traversal flaws in FTP client implementations, highlighting the persistent nature of such security weaknesses in network protocol client applications. The Windows-specific nature of this vulnerability means that exploitation is limited to Windows environments where the Glub Tech Secure FTP client is installed, but the potential for system compromise remains significant.
Mitigation strategies for CVE-2008-2821 primarily focus on software updates and operational security measures. The most effective remediation involves upgrading to Glub Tech Secure FTP version 2.5.16 or later, which includes proper input validation and sanitization of directory path responses. Organizations should also implement network segmentation and firewall rules to limit access to potentially malicious FTP servers, particularly in environments where the vulnerable client is deployed. From an ATT&CK framework perspective, this vulnerability maps to techniques involving file system manipulation and privilege escalation, with the potential for attackers to move laterally within compromised systems once initial access is achieved. Additionally, network monitoring should be enhanced to detect suspicious FTP LIST command responses that contain unusual directory traversal sequences, providing an additional layer of defense against exploitation attempts.