CVE-2005-2742 in Mac OS X
Summary
by MITRE
securityagent in apple mac os x 10.4.2 under certain circumstances can cause the "switch user..." button to appear even though the "enable fast user switching" setting is disabled which can allow attackers with physical access to gain access to the desktop and bypass the "require password to wake this computer from sleep or screen saver" setting.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/11/2019
The vulnerability described in CVE-2005-2742 represents a critical security flaw in Apple Mac OS X 10.4.2's security agent implementation that undermines fundamental user access controls. This issue specifically targets the fast user switching functionality and demonstrates how improper privilege management can create dangerous security loopholes even when system-level protections are ostensibly enabled. The vulnerability operates through a logical flaw in the security agent's decision-making process that governs when the switch user interface elements should be displayed to users.
The technical root cause of this vulnerability lies in the security agent's failure to properly validate the fast user switching setting status before rendering the switch user interface elements. When the "enable fast user switching" setting is explicitly disabled, the system should prevent any user interface elements that would facilitate switching between user accounts from appearing. However, the security agent in question contains a condition that allows the "switch user..." button to appear regardless of the setting status, creating an unexpected pathway for unauthorized access. This flaw represents a violation of the principle of least privilege and demonstrates poor input validation in the security subsystem.
The operational impact of this vulnerability is particularly concerning for physical security scenarios where attackers may have access to a locked computer system. An attacker with physical access to a Mac running OS X 10.4.2 could exploit this vulnerability to bypass the screen saver password protection mechanism, effectively gaining access to the desktop environment without proper authentication. This creates a scenario where the system's built-in security measures are circumvented, allowing unauthorized users to access potentially sensitive information, execute applications, or perform other actions as the logged-in user. The vulnerability essentially provides a backdoor access method that operates at the graphical user interface level rather than through network or system-level attacks.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which describes improper access control issues, and demonstrates how user interface elements can become attack vectors when proper access validation is not enforced. The flaw also relates to ATT&CK technique T1548.001, which covers abuse of system permissions, as it allows unauthorized access to system resources through manipulation of user interface controls. The vulnerability represents a privilege escalation vector that operates at the user session level, allowing an attacker to potentially gain access to other user sessions without proper authentication. Organizations using affected systems should consider this vulnerability as part of their physical security posture assessment, particularly in environments where unauthorized physical access cannot be fully controlled.
The recommended mitigation strategies for this vulnerability include immediate system updates to the latest available security patches from Apple, which would address the flawed logic in the security agent. Additionally, system administrators should consider implementing additional physical security controls such as cable locks, secure workstations, and monitoring procedures to prevent unauthorized physical access to systems. Organizations should also review their security policies to ensure that users understand the importance of locking their screens when stepping away from their computers, as this vulnerability specifically targets scenarios where users are away from their systems but the computer remains unlocked. The vulnerability underscores the importance of comprehensive security testing that includes edge cases and unexpected interaction patterns between system components.