CVE-2009-4795 in Xlight FTP Server
Summary
by MITRE
Multiple SQL injection vulnerabilities in Xlight FTP Server before 3.2.1, when ODBC authentication is enabled, allow remote attackers to execute arbitrary SQL commands via the (1) USER (aka username) or (2) PASS (aka password) command.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2009-4795 represents a critical security flaw in Xlight FTP Server versions prior to 3.2.1 that specifically affects systems utilizing ODBC authentication mechanisms. This vulnerability manifests as multiple SQL injection flaws that can be exploited by remote attackers to execute arbitrary SQL commands against the underlying database system. The attack vector is particularly concerning because it targets the fundamental authentication commands used during FTP session establishment, specifically the USER (username) and PASS (password) commands that are essential for user access control.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the FTP server's authentication processing module. When ODBC authentication is enabled, the server accepts user credentials through the standard FTP protocol commands but fails to properly escape or filter special SQL characters from the username and password parameters. This allows attackers to inject malicious SQL syntax that gets directly executed against the connected database backend. The vulnerability is classified under CWE-89 which specifically addresses SQL injection flaws, where improper sanitization of user inputs leads to unauthorized database access and potential command execution.
The operational impact of this vulnerability is severe and multifaceted across multiple attack vectors. Remote attackers can leverage this flaw to perform unauthorized database queries, potentially gaining access to sensitive user information, credentials, and system data stored in the backend database. The attack can result in complete database compromise, data exfiltration, and potential privilege escalation within the database environment. Additionally, attackers may be able to execute destructive operations such as data modification, deletion, or even system-level commands if the database user account has sufficient privileges. This vulnerability directly maps to several ATT&CK techniques including T1190 (Exploit Public-Facing Application) and T1071.004 (Application Layer Protocol: DNS) where attackers can use the compromised FTP server to establish persistent access and exfiltrate data through database connections.
Mitigation strategies for this vulnerability should prioritize immediate patching of the Xlight FTP Server to version 3.2.1 or later, which contains the necessary input validation fixes. Organizations should also implement network segmentation to limit access to FTP services and consider disabling ODBC authentication if it is not essential for operations. Additional protective measures include implementing database query parameterization, restricting database user privileges, and deploying intrusion detection systems to monitor for suspicious authentication patterns. Network-based firewalls should be configured to restrict FTP service access to trusted IP addresses only, while application-level firewalls can provide additional filtering of SQL injection attempts. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other applications and services that may be susceptible to SQL injection attacks through improper input handling. The vulnerability demonstrates the critical importance of input validation in all authentication mechanisms and highlights the need for comprehensive security testing of database-connected applications.