CVE-1999-0629 in Host
Summary
by MITRE
The ident/identd service is running.
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Analysis
by VulDB Data Team • 10/24/2025
The CVE-1999-0629 vulnerability represents a fundamental security oversight in network infrastructure services, specifically identifying the presence of an ident/identd service that is actively running on a system. This service operates on TCP port 113 and was originally designed to provide authentication information about users connecting to a system, but it has become a significant security concern in modern network environments. The ident service was intended to help systems identify the user associated with a particular connection, but its implementation has proven to be largely ineffective for security purposes while providing attackers with additional attack surface.
The technical flaw in this vulnerability stems from the inherent design limitations of the ident protocol itself, which operates without any form of authentication or encryption. The ident service functions by responding to queries from other systems to identify the user associated with a particular TCP connection, but it provides no meaningful security benefits while creating potential entry points for malicious actors. According to CWE-200, this represents an information exposure vulnerability where system information is unnecessarily exposed to potential attackers. The service operates as a passive listener that responds to connection requests without proper authentication mechanisms, making it susceptible to various exploitation techniques.
The operational impact of running an ident service extends beyond simple information disclosure, as it provides attackers with additional reconnaissance data that can be used in conjunction with other attacks. The service can reveal user accounts, connection details, and system information that would otherwise remain hidden, potentially enabling more sophisticated attacks such as privilege escalation or targeted social engineering campaigns. From an ATT&CK framework perspective, this vulnerability maps to T1082 (System Information Discovery) and T1592 (Gather Victim Host Information) as it provides adversaries with system reconnaissance capabilities. The presence of this service can also complicate security audits and compliance assessments, as it represents an unnecessary service running on the system that could be exploited by threat actors.
Mitigation strategies for CVE-1999-0629 should focus on eliminating the ident service entirely from systems where it is not strictly required for legacy applications. System administrators should disable the ident service through proper service management configurations and ensure that it is not automatically started during system boot processes. Network segmentation and firewall rules should be implemented to block access to port 113 from unauthorized networks, preventing external systems from querying the ident service. Additionally, regular security audits should be conducted to identify and remove any unnecessary services that could provide attack vectors, aligning with NIST SP 800-53 security controls that emphasize the importance of minimizing attack surface through service reduction and proper access controls. Organizations should also implement continuous monitoring to detect unauthorized ident service activity and establish proper incident response procedures for identifying and remediating such vulnerabilities.