CVE-2009-0151 in Mac OS X
Summary
by MITRE
The screen saver in Dock in Apple Mac OS X 10.5 before 10.5.8 does not prevent four-finger Multi-Touch gestures, which allows physically proximate attackers to bypass locking and "manage applications or use Expose" via unspecified vectors.
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Analysis
by VulDB Data Team • 08/13/2021
The vulnerability described in CVE-2009-0151 represents a significant security flaw in the macOS operating system's dock screen saver implementation. This issue affects Mac OS X 10.5 versions prior to 10.5.8, where the screen saver functionality fails to properly restrict access to core system interaction mechanisms. The flaw specifically relates to the dock's screen saver behavior and its inability to prevent four-finger Multi-Touch gestures from being processed while the system is locked. This represents a critical authorization bypass vulnerability that undermines the fundamental security model of the operating system's lock screen protection mechanisms.
The technical nature of this vulnerability stems from the improper handling of Multi-Touch gesture events within the dock's screen saver context. When a Mac system enters screen saver mode, legitimate security protocols should prevent unauthorized interaction with the user interface to maintain system integrity and protect user data. However, the flaw allows proximity-based physical attackers to circumvent these protections through Multi-Touch gestures that are typically restricted when the system is locked. The unspecified vectors mentioned in the description suggest that multiple attack paths exist, potentially involving different combinations of gesture sequences or physical positioning relative to the device. This type of vulnerability falls under the category of unauthorized access through physical proximity attacks, which can be classified as a CWE-284 (Improper Access Control) issue.
The operational impact of this vulnerability is substantial as it enables attackers to gain unauthorized access to system management functions while the device appears to be locked. An attacker with physical proximity to a locked Mac system can potentially manage applications, access system resources, or utilize Expose functionality without proper authentication. This creates a scenario where sensitive data and system controls become accessible to unauthorized individuals who are simply present near the device. The vulnerability essentially provides a backdoor mechanism that bypasses the standard lock screen security controls, potentially allowing for data theft, system manipulation, or further exploitation of other security weaknesses. From an attack perspective, this represents a low-barrier attack vector that does not require sophisticated technical skills or specialized equipment beyond physical access to the device.
Mitigation strategies for this vulnerability should focus on updating to the patched version of Mac OS X 10.5.8 or later, which addresses the screen saver gesture handling issue. System administrators should implement comprehensive patch management procedures to ensure all affected systems receive the necessary security updates. Organizations should also consider implementing additional physical security measures such as device encryption, automatic screen locking after periods of inactivity, and user education about the risks of leaving devices unattended. The vulnerability highlights the importance of proper input validation and access control in graphical user interfaces, particularly in contexts where security boundaries are being enforced. From a compliance perspective, this type of vulnerability could impact organizations that must maintain strict security controls and may need to demonstrate proper patch management processes to meet regulatory requirements. This issue demonstrates the ongoing challenge of securing modern operating systems where multiple interaction methods and gesture-based controls must properly respect security boundaries.