CVE-2006-4387 in Mac OS X
Summary
by MITRE
Apple Mac OS X 10.4 through 10.4.7, when the administrator clears the "Allow user to administer this computer" checkbox in System Preferences for a user, does not remove the user's account from the appserveradm or appserverusr groups, which still allows the user to manage WebObjects applications.
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Analysis
by VulDB Data Team • 04/23/2026
This vulnerability exists in Apple Mac OS X versions 10.4 through 10.4.7 where administrative privileges are not properly revoked when a user account is removed from the administrator group through System Preferences. The flaw specifically affects the WebObjects application management functionality and represents a privilege escalation issue that violates fundamental security principles of least privilege and access control. When administrators clear the "Allow user to administer this computer" checkbox, the system fails to properly remove the user from critical system groups including appserveradm and appserverusr, leaving users with continued access to administrative functions despite having been explicitly demoted from administrative status. This creates a persistent security risk where former administrators can continue to manage WebObjects applications without proper authorization.
The technical mechanism behind this vulnerability involves improper privilege revocation within the Mac OS X system administration framework. The system correctly removes the user from the general administrator group but neglects to update the specialized WebObjects application server groups that control access to the application server management interface. This represents a classic case of incomplete access control list maintenance where the user retains membership in groups that grant specific application-level privileges. The vulnerability stems from a design flaw in the privilege management system that fails to synchronize group membership changes across all relevant system groups, creating an inconsistent security state. From a cybersecurity perspective, this represents a failure in the principle of least privilege as defined by the CWE-255 weakness category, where users maintain unnecessary privileges beyond their intended scope.
The operational impact of this vulnerability is significant for system administrators who rely on the standard user demotion process to revoke administrative access. Attackers or malicious insiders who gain access to a user account can potentially exploit this flaw to maintain administrative access to WebObjects applications even after being removed from the general administrator group. This creates a persistent backdoor that undermines the security model of the operating system and compromises the integrity of the administrative access control system. The vulnerability affects the core system administration functionality and can lead to unauthorized application management, configuration changes, and potential data exposure through the WebObjects application server interface. The persistence of this access makes it particularly dangerous as it can remain undetected for extended periods, especially in environments where regular security audits are not conducted.
Mitigation strategies should focus on immediate remediation through system updates to the latest available Mac OS X versions that address this privilege management flaw. System administrators should implement manual verification procedures to ensure that user accounts are properly removed from all relevant system groups when demoting users from administrative status. The recommended approach includes checking and manually removing affected users from appserveradm and appserverusr groups through command line tools or system administration interfaces. Organizations should also implement regular security audits that verify group membership and access control configurations to identify and remediate similar privilege escalation vulnerabilities. This vulnerability highlights the importance of comprehensive access control management and proper privilege revocation procedures, aligning with the ATT&CK technique T1078 for Valid Accounts and T1548.001 for Abuse of System Permissions, where attackers can maintain persistent access through improper privilege management. The security community should consider this vulnerability as a prime example of why automated privilege management systems are essential in preventing such persistent access control flaws.