CVE-2004-2532 in Serv-U
Summary
by MITRE
Serv-U FTP server before 5.1.0.0 has a default account and password for local administration, which allows local users to execute arbitrary commands by connecting to the server using the default administrator account, creating a new user, logging in as that new user, and then using the SITE EXEC command.
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Analysis
by VulDB Data Team • 08/19/2025
The vulnerability identified as CVE-2004-2532 affects Serv-U FTP server versions prior to 5.1.0.0 and represents a critical security flaw that stems from poor default configuration practices. This issue arises from the inclusion of hardcoded default administrative credentials within the software installation, creating a persistent backdoor that remains active regardless of system updates or user configuration changes. The vulnerability specifically targets local users who possess access to the system where the FTP server is installed, making it particularly dangerous in environments where local privileges are not strictly controlled.
The technical exploitation of this vulnerability follows a well-defined sequence that leverages the default administrative account credentials to establish unauthorized access. Attackers can connect to the FTP server using the hardcoded administrator credentials, which typically remain unchanged across installations. Once authenticated, the malicious user can create a new FTP user account with elevated privileges, then switch to that newly created account to execute commands. The critical exploitation vector involves the SITE EXEC command, which allows arbitrary command execution on the underlying operating system. This command processing mechanism bypasses normal authentication checks and directly invokes system shell commands, enabling attackers to perform actions ranging from file manipulation to complete system compromise.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with persistent administrative capabilities within the targeted system. The default account credentials remain active even after system reboots or software updates, creating a long-term security risk that can be exploited by anyone who knows the default login details. This vulnerability aligns with CWE-798, which addresses the use of hard-coded credentials, and represents a classic example of insecure default configuration. The attack surface is particularly concerning in multi-user environments where local access is not properly restricted, as it allows unauthorized users to escalate privileges and gain complete control over the system's file operations and underlying processes.
The security implications of CVE-2004-2532 are amplified by its alignment with several ATT&CK framework techniques, particularly those related to privilege escalation and command execution. The vulnerability enables adversaries to move laterally within a system by leveraging the default administrative account, and can be used to establish persistent access through the creation of new user accounts. The SITE EXEC command execution capability directly maps to ATT&CK technique T1059, which covers command and script execution, while the default credential usage corresponds to T1566, targeting credential access through default credentials. Organizations affected by this vulnerability face significant risks including data exfiltration, system corruption, and potential use as a foothold for broader network attacks.
Mitigation strategies for this vulnerability require immediate action to address the hardcoded credentials and implement proper access controls. The primary recommendation involves upgrading to Serv-U FTP server version 5.1.0.0 or later, which removes the default administrative account and implements proper authentication mechanisms. System administrators should also conduct comprehensive audits of all installed software to identify similar hardcoded credentials across other applications. Additional protective measures include implementing strict local access controls, monitoring FTP server logs for unauthorized access attempts, and disabling unnecessary administrative accounts. The vulnerability serves as a critical reminder of the importance of secure configuration management and proper credential handling practices, aligning with industry standards that emphasize the need for default accounts to be disabled or changed immediately upon installation. Organizations should also implement network segmentation to limit local access to critical systems and establish robust patch management processes to ensure timely updates of all software components.