CVE-2008-6514 in Compiz Fusion
Summary
by MITRE
The Expo plugin in Compiz Fusion 0.7.8 allows local users with physical access to drag the screen saver aside and access the locked desktop by using Expo mouse shortcuts, a related issue to CVE-2007-3920.
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Analysis
by VulDB Data Team • 08/31/2019
The vulnerability described in CVE-2008-6514 affects the Expo plugin within Compiz Fusion version 0.7.8, representing a significant security flaw that undermines desktop lock mechanisms. This issue specifically targets systems utilizing the Compiz window manager framework, where the Expo plugin provides a visual desktop overview feature that allows users to navigate between multiple virtual desktops. The vulnerability arises from insufficient access controls and improper handling of user interactions during the screen saver lock process, creating an exploitable condition that can be leveraged by local attackers with physical access to the system.
The technical flaw stems from the Expo plugin's failure to properly enforce access restrictions when screen saver locks are active. When a user locks their desktop, the screen saver should prevent unauthorized access to the underlying desktop environment through any interface elements. However, this vulnerability allows attackers to utilize mouse shortcuts specifically designed for the Expo functionality to bypass these protective measures. The exploit relies on the fact that the Expo plugin continues to respond to user input even when the desktop is locked, enabling the attacker to manipulate the visual desktop overview and potentially gain access to locked applications and data. This represents a direct violation of the fundamental security principle that locked desktop environments should be completely inaccessible to unauthorized users.
The operational impact of this vulnerability extends beyond simple privacy concerns to potentially expose sensitive data and system resources. Local users with physical access can exploit this weakness to access locked desktop environments, potentially gaining access to confidential documents, communications, and system configurations. The vulnerability is particularly concerning because it requires minimal technical expertise to exploit and can be executed through simple mouse interactions. Attackers can effectively circumvent the security controls designed to protect against unauthorized access, creating a vector for data theft, system compromise, and potential escalation of privileges. The related vulnerability CVE-2007-3920 indicates this represents a broader class of issues within the Compiz framework, suggesting that similar weaknesses may exist in other components of the system.
Security mitigations for this vulnerability should focus on implementing proper access controls and ensuring that all user interface elements remain disabled during screen saver lock states. System administrators should update to patched versions of Compiz Fusion that address this specific issue, as well as implement additional security measures such as disabling unnecessary visual effects when screen savers are active. The vulnerability aligns with CWE-284, which addresses improper access control, and relates to ATT&CK technique T1547.001 for registry run keys and startup folder, as the exploitation could potentially lead to persistence mechanisms. Organizations should also consider implementing additional physical security measures and monitoring for unauthorized access attempts, particularly in environments where physical access controls are insufficient. The vulnerability demonstrates the importance of comprehensive security testing that includes evaluating the interaction between different system components during security-critical states such as screen lock activation.