CVE-1999-0713 in Unix
Summary
by MITRE
The dtlogin program in Compaq Tru64 UNIX allows local users to gain root privileges.
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Analysis
by VulDB Data Team • 04/19/2026
The dtlogin program in Compaq Tru64 UNIX represents a critical privilege escalation vulnerability that has significant implications for system security. This vulnerability specifically affects the desktop login component of the Tru64 UNIX operating system, which is a proprietary Unix variant developed by Compaq for their Alpha processor architecture. The flaw exists within the program's handling of user authentication and privilege management, creating an exploitable condition that allows local attackers to elevate their privileges to the root level without requiring authentication. The vulnerability is particularly concerning because it operates at the system level and does not require network access or specialized knowledge beyond local system access.
The technical implementation of this vulnerability stems from improper privilege management within the dtlogin program's execution flow. When the program processes user authentication requests, it fails to properly validate or restrict the privileges associated with certain operations that should only be executable by the root user. This flaw likely involves inadequate checks on the effective user ID or group ID during program execution, allowing local users to manipulate the program's behavior to gain elevated privileges. The vulnerability may involve improper handling of setuid bits, race conditions in privilege checking, or buffer overflow conditions that can be exploited through crafted input. According to the Common Weakness Enumeration framework, this vulnerability would be classified as a privilege escalation weakness, potentially falling under CWE-269 for improper privilege management or CWE-787 for out-of-bounds write conditions that could lead to privilege escalation.
The operational impact of CVE-1999-0713 is substantial for organizations running Compaq Tru64 UNIX systems, as it provides a direct path to complete system compromise. Local users who can execute the dtlogin program gain unrestricted access to all system resources, including the ability to modify critical system files, install malicious software, access sensitive data, and potentially establish persistent backdoors. This vulnerability effectively neutralizes the security boundary between regular user accounts and the root administrative account, fundamentally undermining the principle of least privilege that is central to secure system design. The impact extends beyond immediate privilege escalation, as attackers can use the root access to modify system configurations, disable security mechanisms, and conduct further reconnaissance or lateral movement within the network infrastructure. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1068 for local privilege escalation, enabling attackers to achieve higher system access levels without requiring additional attack vectors or complex exploitation techniques.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The primary recommendation involves applying the vendor-provided security patches or updates that fix the privilege escalation flaw in the dtlogin program. Organizations should also implement comprehensive system hardening measures, including regular security audits, proper privilege management, and monitoring for unauthorized access attempts. System administrators should consider implementing additional access controls and logging mechanisms to detect potential exploitation attempts. The vulnerability highlights the importance of proper privilege separation and the need for robust input validation in system components that handle user authentication and authorization. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other system components, as this vulnerability demonstrates the potential for privilege escalation flaws in desktop environment applications. The incident underscores the necessity of maintaining up-to-date security patches and the importance of understanding the security implications of all system components, particularly those that handle user authentication and privilege management.