CVE-2000-0040 in glFtpD
Summary
by MITRE
glFtpD allows local users to gain privileges via metacharacters in the SITE ZIPCHK command.
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Analysis
by VulDB Data Team • 10/19/2025
The vulnerability identified as CVE-2000-0040 affects the glFtpD FTP server implementation, representing a privilege escalation flaw that exploits metacharacters within the SITE ZIPCHK command. This vulnerability resides in the command processing logic of the FTP daemon where improper input validation allows malicious users to manipulate command parameters and execute unauthorized operations with elevated privileges. The issue stems from the server's insufficient sanitization of user-supplied data within the SITE command execution context, creating a pathway for local attackers to bypass normal access controls and escalate their privileges within the system.
The technical exploitation of this vulnerability occurs through the manipulation of metacharacters within the SITE ZIPCHK command, which is typically used for verifying zip file integrity on the FTP server. When the server processes this command without proper validation of the input parameters, it becomes susceptible to command injection attacks. Attackers can craft specific metacharacter sequences that cause the FTP daemon to execute unintended shell commands with the privileges of the running service account. This represents a classic command injection vulnerability where the lack of input filtering creates a direct pathway for arbitrary code execution. The vulnerability falls under CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and demonstrates how FTP protocol implementations can expose systems to privilege escalation through inadequate input validation.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to gain unauthorized access to system resources, modify critical files, and potentially establish persistent access within the network environment. Local users who can connect to the FTP service can leverage this flaw to execute commands with elevated privileges, potentially compromising the entire system. The vulnerability is particularly concerning because it allows local privilege escalation without requiring remote network access, making it a significant threat in environments where local accounts are present. Attackers can use this vulnerability to access sensitive data, modify system configurations, or establish backdoors that persist across system reboots, as the elevated privileges provide access to system-level resources and processes.
Mitigation strategies for CVE-2000-0040 should focus on implementing proper input validation and sanitization within the FTP server's command processing logic. The primary defense involves modifying the SITE ZIPCHK command implementation to properly validate and sanitize all user-supplied input parameters, eliminating the use of metacharacters that could be interpreted as command separators or operators. System administrators should ensure that the FTP daemon is updated to a version that properly handles command parameters without allowing shell injection. Additionally, implementing proper access controls and privilege separation can reduce the impact of such vulnerabilities, as the service should run with minimal required privileges. The vulnerability also highlights the importance of following secure coding practices and adhering to the principle of least privilege as outlined in the ATT&CK framework's privilege escalation techniques, where attackers can leverage application-level flaws to gain elevated system access. Organizations should also consider implementing network segmentation and monitoring to detect unauthorized FTP access attempts and command execution patterns that may indicate exploitation of this vulnerability.