CVE-2002-0444 in Windows
Summary
by MITRE
Microsoft Windows 2000 running the Terminal Server 90-day trial version, and possibly other versions, does not apply group policies to incoming users when the number of connections to the SYSVOL share exceeds the maximum, e.g. with a maximum number of licenses, which can allow remote authenticated users to bypass group policies.
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Analysis
by VulDB Data Team • 09/17/2025
This vulnerability exists in Microsoft Windows 2000 Terminal Server implementations where group policy enforcement fails when connection limits are reached on the SYSVOL share. The flaw occurs specifically during the authentication process when the system cannot properly apply security policies to incoming users due to connection saturation. The vulnerability stems from improper handling of resource limitations in the Terminal Services environment where the maximum number of concurrent connections to the SYSVOL directory is reached, preventing proper policy application.
The technical implementation of this vulnerability involves the Windows Terminal Services architecture where user authentication and group policy application occur through the SYSVOL share which hosts the group policy objects. When the maximum connection limit is exceeded, typically due to license constraints or connection pooling limits, the system fails to process incoming user connections through the standard authentication pipeline that includes group policy evaluation. This creates a scenario where authenticated users can establish sessions without having their security policies properly enforced, effectively bypassing the intended access controls and security configurations.
The operational impact of this vulnerability is significant as it allows remote authenticated users to gain unauthorized access to systems with reduced security controls. Attackers can exploit this by establishing multiple connections to reach the maximum limit, then authenticate additional users who will bypass the group policy enforcement mechanisms. This creates a persistent security risk where malicious users can establish sessions with elevated privileges or access to resources that should be restricted by the configured group policies. The vulnerability particularly affects organizations relying on Terminal Services for remote access and those with strict security policy enforcement requirements.
This vulnerability maps to CWE-284 Access Control Bypass and aligns with ATT&CK technique T1078 Valid Accounts, where adversaries leverage legitimate credentials to access systems while bypassing security controls. The issue represents a privilege escalation vector where authenticated users can circumvent the normal security enforcement mechanisms that should apply to all connections. Organizations using Terminal Services should implement immediate mitigations including monitoring connection limits, enforcing stricter session management policies, and ensuring adequate licensing to prevent connection saturation. Additional protective measures include implementing network segmentation, monitoring SYSVOL share access patterns, and regularly auditing group policy application processes to detect potential exploitation attempts.
The vulnerability demonstrates the importance of proper resource management in authentication systems where connection limits can inadvertently create security gaps. Microsoft addressed this through updates that improved the handling of connection limits and ensured consistent group policy enforcement regardless of connection saturation conditions. Organizations should ensure their Terminal Services implementations are properly licensed and monitored to prevent reaching connection limits that could trigger this vulnerability, as the bypass of group policies can lead to unauthorized access to sensitive system resources and data.