CVE-2002-1933 in Windows
Summary
by MITRE
The terminal services screensaver for Microsoft Windows 2000 does not automatically lock the terminal window if the window is minimized, which could allow local users to gain access to the terminal server window.
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Analysis
by VulDB Data Team • 07/06/2024
The vulnerability described in CVE-2002-1933 represents a significant security flaw in Microsoft Windows 2000 terminal services implementation that directly impacts session management and access control mechanisms. This issue specifically affects the screensaver functionality within the terminal services environment, creating a persistent security gap that local attackers can exploit to gain unauthorized access to active terminal server sessions. The vulnerability exists at the operating system level within the Windows 2000 terminal services subsystem, where the screensaver component fails to properly enforce session locking policies when users minimize terminal windows, thereby undermining the fundamental security assumptions of terminal server access control.
The technical flaw manifests in the improper handling of terminal window states during screensaver activation. When a user minimizes a terminal services window, the system should automatically lock the session to prevent unauthorized access, but this locking mechanism fails to activate in the minimized state. This behavior creates a window of opportunity where local users can observe and potentially manipulate terminal server sessions without proper authentication. The vulnerability stems from inadequate state management within the terminal services screensaver component, where the system does not properly distinguish between active and minimized window states when executing security protocols. This issue falls under the category of improper access control mechanisms, specifically related to session management and authentication state handling.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially enable more sophisticated attacks within terminal server environments. Local users who exploit this vulnerability can observe active sessions, potentially gaining access to sensitive data, system resources, or other users' credentials without proper authentication. This weakness particularly affects enterprise environments where terminal servers are commonly used for remote access and administrative tasks, as it allows attackers to maintain access to systems they might not otherwise be able to reach. The vulnerability creates a persistent threat vector that can be exploited repeatedly, as the window of opportunity remains open until the user manually locks the session or the system properly activates the screensaver functionality.
Organizations using Windows 2000 terminal services should implement immediate mitigations to address this vulnerability, including manual session locking procedures, enhanced monitoring of terminal server sessions, and deployment of additional access control measures. The recommended approach involves configuring terminal services to enforce automatic session locking regardless of window state, implementing stricter local access controls, and establishing regular security audits of terminal server environments. This vulnerability demonstrates the importance of comprehensive security testing across all system components, particularly those related to session management and access control. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and credential access, specifically targeting the local system access and credential dumping capabilities. The issue also relates to CWE-284, which addresses improper access control, and highlights the critical need for proper session management in multi-user environments where security boundaries must be maintained between different user contexts and access levels.