CVE-2001-0768 in GuildFTPd
Summary
by MITRE
GuildFTPd 0.9.7 stores user names and passwords in plaintext in the default.usr file, which allows local users to gain privileges as other FTP users by reading the file.
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Analysis
by VulDB Data Team • 07/16/2019
The vulnerability identified as CVE-2001-0768 affects GuildFTPd version 0.9.7, a widely used FTP server implementation that was prevalent during the early 2000s. This security flaw represents a critical misconfiguration in how the software handles user authentication data, specifically exposing a fundamental weakness in the system's credential storage mechanisms. The issue manifests when the default configuration fails to properly secure sensitive information, leaving user credentials accessible to any local user with file system access. This represents a classic case of poor security implementation where the software does not follow established security best practices for credential management.
The technical flaw resides in the default file storage mechanism where user names and passwords are persisted in plaintext format within the default.usr file. This file contains all user authentication details in an easily readable format without any form of encryption or obfuscation. When a local attacker gains access to the system, they can simply read this file to obtain valid credentials for other FTP users, effectively bypassing all authentication mechanisms that should protect user accounts. The vulnerability stems from the application's failure to implement proper access controls or encryption for sensitive data, directly violating security principles outlined in various security frameworks including those referenced in CWE-312 and CWE-522. The plaintext storage of credentials creates an immediate and severe risk for privilege escalation attacks.
The operational impact of this vulnerability extends far beyond simple credential theft, as it enables unauthorized users to assume the identities of legitimate FTP users and gain access to all associated resources and permissions. This creates a significant risk for data breaches, unauthorized file access, modification, or deletion, and potential lateral movement within network environments where FTP services are deployed. Attackers can leverage this vulnerability to gain persistent access to systems, escalate privileges, and conduct further reconnaissance or malicious activities without detection. The local privilege escalation aspect of this vulnerability means that even users who initially have limited access can exploit this flaw to gain broader system access, making it particularly dangerous in multi-user environments where different users have varying levels of access rights. This vulnerability aligns with ATT&CK technique T1078.004 which covers legitimate credentials, and represents a classic example of credential dumping that can be exploited in various attack scenarios.
Mitigation strategies for this vulnerability require immediate attention through multiple layers of security controls. The primary remediation involves ensuring that user credentials are stored using proper encryption mechanisms or at minimum, implementing strict file system access controls that prevent unauthorized local users from reading the credential file. System administrators should configure the FTP server to use encrypted storage for user credentials, implement proper file permissions, and consider using alternative authentication mechanisms such as PAM or LDAP integration. Additionally, regular security audits should be conducted to ensure that default configurations are not left in place, and that all system components follow security best practices. The vulnerability highlights the importance of following security guidelines such as those outlined in NIST SP 800-53 and ISO/IEC 27001, which emphasize the protection of sensitive information and proper access control implementations. Organizations should also implement monitoring solutions to detect unauthorized access attempts to credential files and establish regular patching procedures to address similar vulnerabilities in other software components.