CVE-2005-2496 in ntpd
Summary
by MITRE
The xntpd ntp (ntpd) daemon before 4.2.0b, when run with the -u option and using a string to specify the group, uses the group ID of the user instead of the group, which causes xntpd to run with different privileges than intended.
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Analysis
by VulDB Data Team • 06/30/2025
The vulnerability described in CVE-2005-2496 affects the ntpd daemon version 4.2.0b and earlier, specifically when executed with the -u option and using a string to specify the group. This issue represents a privilege escalation concern that undermines the intended security model of the network time protocol daemon. The flaw occurs during the daemon's initialization phase when it processes group specifications, creating a discrepancy between the intended operational privileges and the actual execution context. The vulnerability stems from improper handling of group identification parameters, where the system fails to correctly resolve the group identifier from the provided string, instead defaulting to the user's primary group ID.
This technical flaw directly relates to CWE-250, which addresses execution with unnecessary privileges, and demonstrates how improper privilege management can create security weaknesses in network services. The operational impact of this vulnerability is significant as it allows an attacker to potentially execute the ntpd daemon with unintended privileges, possibly elevating their access level within the system. When the daemon runs with incorrect group privileges, it may operate with broader permissions than initially intended, creating potential attack vectors for privilege escalation and unauthorized system access. The issue becomes particularly concerning in environments where ntpd is configured to run with elevated privileges or where the group specification is manipulated by untrusted users.
The security implications extend beyond simple privilege confusion, as this vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation'. Attackers could potentially exploit this weakness to gain elevated system privileges or manipulate time synchronization services in ways that compromise system integrity. The vulnerability's impact is amplified when considering that ntpd typically requires elevated privileges to function properly, and improper group handling could result in the daemon operating with more permissions than necessary for its time synchronization duties. System administrators should note that this issue affects the daemon's security posture during startup and initialization, potentially creating persistent security weaknesses that could be exploited by local or network-based attackers.
Mitigation strategies should focus on immediate patching of the ntpd daemon to version 4.2.0b or later, where this vulnerability has been resolved. Additionally, system administrators should implement proper privilege separation practices, ensuring that the daemon runs with the minimum necessary permissions and that group specifications are properly validated. The vulnerability highlights the importance of proper input validation and privilege management in network services, particularly those that require elevated system privileges to operate. Organizations should conduct thorough security reviews of their time synchronization configurations and verify that all network services properly handle user and group identification parameters to prevent similar privilege escalation scenarios.