CVE-2007-0739 in Mac OS X
Summary
by MITRE
The Login Window in Apple Mac OS X 10.4 through 10.4.9 displays the software update window beneath the loginwindow authentication dialog in certain circumstances related to running scheduled tasks, which allows local users to bypass authentication controls.
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Analysis
by VulDB Data Team • 07/14/2021
The vulnerability described in CVE-2007-0739 represents a critical authentication bypass issue within Apple Mac OS X 10.4 through 10.4.9 operating systems. This flaw manifests in the Login Window component where the software update window becomes visible beneath the authentication dialog, creating an unexpected interaction that compromises the security model of the system. The vulnerability specifically occurs during scheduled task execution when the system attempts to display software updates while the user is in the process of authenticating to the system.
The technical root cause of this vulnerability stems from improper window management and z-order handling within the Mac OS X login interface. When scheduled tasks are executed and the system attempts to display software update notifications, the window hierarchy becomes disrupted, causing the update window to appear underneath the authentication dialog rather than properly managing the display stack. This window management flaw allows an attacker to potentially interact with the software update interface while the authentication process is still active, creating an opportunity for bypassing the normal authentication controls. The vulnerability operates under the principle of improper access control and window management security issues that can be categorized under CWE-284, which addresses improper access control in software systems.
The operational impact of this vulnerability is significant for local users who may exploit the window stacking behavior to gain unauthorized access to system resources. An attacker with physical access to a Mac system running the affected versions could potentially manipulate the display to view or interact with the software update interface while authentication is still required, potentially allowing them to bypass the login process or access system functions that should remain restricted. This represents a serious compromise of the system's security model, as the authentication mechanism that should prevent unauthorized access becomes ineffective due to the improper window handling behavior.
The vulnerability demonstrates how seemingly minor interface design flaws can create substantial security implications, particularly in authentication systems where the user interface directly interacts with security controls. This issue highlights the importance of proper window management and z-order handling in security-critical components of operating systems. The problem can be addressed through proper window stacking management, ensuring that authentication dialogs maintain proper focus and visibility priority over other system interfaces, and implementing robust access control mechanisms that are not susceptible to display layer manipulation.
Mitigation strategies for this vulnerability should include immediate system updates to patched versions of Mac OS X, as well as proper system administration practices to monitor for scheduled tasks that might trigger this behavior. Organizations should implement security policies that prevent unauthorized local access to systems, maintain updated software versions, and conduct regular security assessments of their Mac OS X environments. The vulnerability also underscores the need for comprehensive security testing of user interface components, particularly those involved in authentication and access control, to ensure that display behaviors do not inadvertently compromise security controls. This issue aligns with ATT&CK technique T1068 which addresses local privilege escalation through improper system configuration or interface design flaws that allow bypass of authentication mechanisms.